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The occurrence of the shallow-water sergestid shrimp Acetes sibogae sibogae Hansen, 1919\n(Crustacea, Decapoda, Sergestidae) in Japan has been confirmed. This is the first record of this species and\nreflects a notable northward range expansion to Okinawa-jima Island, Ryukyu Archipelago, Japan., 論文

本稿では，動物プランク卜ンとして重要なカイアシ類，アミ類に共生する繊毛虫の生活史，生態，生態的機能について概説する。なお，「共生」に関する厳密な定義は困難である場合があるが(Bush et al. 2001)， ここでは相利共生，片利共生，寄生，捕食寄生，便乗なども含む広義の意味で「共生」という言葉を使用し，宿主と共生生物との種間関係が明確でない場合も「共生」という言葉を使用する。通常，宿主が共生生物より体サイズが大きく，宿主と共生生物間に食関係か成立していて宿主になんらかの悪影響がある場合を「寄生」，宿主を確実に死に至らしめる場合を「捕食寄生」と呼ぶこととする。

Mysid crustaceans are subject to infestation by a variety of organisms, but little attention has been paid to the biological interaction between the hosts and their parasites. Recent studies have revealed higher diversity of parasitism in mysids than was thought previously. The present paper briefly reviews recent studies on interactions between mysids and their parasites. Ciliates are common epibionts on mysids. Some peritrich ciliates have close relationships with intertidal species of Archaeomysis in the northwestern Pacific. The host-specificity, attachment site preference, and geographical cline of the ciliates are remarkable along the coasts of Japan. In Ishikari Bay, northern Japan, the prevalence of the ciliates is maintained at high levels throughout the year, indicating that the ciliates are capable of re-attaching on the fresh exoskeleton of mysids immediately after the molt of the hosts takes place. Eggs/embryos within the female marsupium are free from these epibionts. Infection of some ellobiopsids adversely impacts on host crustaceans including mysids by inducing a reduction in development and reproduction, castration, and/or intersex. Some crustacean parasites found within the host marsupium such as nicothoid copepods and epicaridean isopods greatly influence host population dynamics, because of their relatively high incidence and devouring of host eggs/embryos. In the Seto Inland Sea, western Japan, these two parasites occur on Siriella okadai and seem to compete severely over the habitat (marsupium) and foods (eggs/embryos) of the host mysid.

Rhopalophthalmus armiger Hanamura & Murano sp. nov. (Figs. 11���13) Rhopalophthalmus longipes ��� Ii, 1964, fig. 47 n. ��� Wang & Liu 1994: 91 (?in part). ��� Liu & Wang 2000: 114 (?in part). Rhopalophthalmus egregious ��� W. Tattersall 1936: 147. Rhopalophthalmus macropsis ��� Pillai 1973: 56, fig. 24. Material examined. Holotype. South China Sea. South-western part of South China Sea: male (BL ca. 14 mm); RV Hakuho-maru cruise KH- 72 - 1, St. 50, 06�� 51.6 ' N, 108 �� 47.2 ' E to 06�� 51.6 ' N, 108 �� 48.9 ' E, plankton net installed at mouth of 3 m beam trawl, 132���137 m depth, 11 July 1972, coll. M. Murano (NSMT 21225). Paratypes. South-western part of South China Sea: 64 males (BL ca. 7.0��� 15 mm), 78 females (BL ca. 8.5���16 mm), 20 ovig. females (BL ca. 11���16 mm), 23 juvs. (BL ca. 5.5 ���7.0 mm) (most of them more or less damaged); data same as for holotype (NSMT 21226). Additional material examined. South China Sea. Off Vietnam: 1 juv. (BL ca. 6 mm); RV Hijun-maru, 16 �� 18 ��� N, 108 �� 27 ��� E, 24 Jan 1933, coll. N. Ii (No. 138 in Ii 1964). ��� Southern part of South China Sea: 1 juv. (BL ca. 4 mm); RV Hijun-maru, St. 50, 3�� 53 ' N, 110 �� 13 ' E, 27 Feb 1933, coll. N. Ii (NSMT Cr 21227). ��� 1 female (BL ca. 8.0 mm), 5 juvs. (BL ca. 5.0���6.0 mm); RV Hakuho-maru cruise KH- 72 - 1, St. 45, 05�� 13.5 ' N, 107 ��00.8' E to 05�� 13.7 ' E, 107 ��01.1' E, plankton net installed at mouth of 3 m beam trawl, 60 m depth, 10 July 1972, coll. M. Murano (NSMT Cr 21229). ��� Northern part of South China Sea: 1 female (BL 8.5 mm); RV Hakuho-maru cruise KH- 73 - 2, St. 41, 22�� 15.3 ' N, 115 �� 28.2 ' E to 22 �� 15.7 ' E, 115 �� 28.9 ' E, 00: 50 ���01: 50, plankton net installed at mouth of 3 m beam trawl, 50���55 m depth, 18 Mar 1973, coll. M. Murano (NSMT Cr 21230). Timor Sea. North-western part of Timor Sea: 2 females (BL ca. 5, 5.5 mm), 1 abdomen; RV Hakuho-maru cruise KH- 72 - 1, St. 29, 12�� 17.3 ' S, 129 �� 40.9 ' E to 12 �� 17.2 ' S, 124 �� 36.4 ' E, plankton net installed at mouth of 3 m beam trawl, 49���52 m depth, 24 June 1972, coll. M. Murano (NSMT Cr 21231). Australia. Outside Trinity Opening, NSW: 1 female (BL ca. 5.5 mm; damaged); Great Barrier Reef Expedition, St. 29, Bottom Strain Net, 24 June 1928 (NHM 1936.10.8.55). Description. Body (Fig. 11 a) moderately stout, somewhat large among eastern Asian members of Rhopalophthalmus. Anterior dorsal part of carapace between postorbital spines slightly produced, forming evenly rounded rostral plate (Figs. 11 a���d); postorbital spine sharp, supported by short carina; cervical groove marked dorsally and laterally around anterior one-third; antero-median nodule small, sometimes indistinct due to fragile nature of carapace but often prominent in young specimens, posterior nodule marked well, posterior dorsal margin excavate dorsally, leaving last 3 thoracic somites uncovered in dorsal view; cheeks sinuous; antero-lateral spine comparatively short, falling slightly short of anterior end of rostral plate. Eyes (Figs. 11 a���d) somewhat globular, falling short of end of second segment of antennular peduncle, cornea well pigmented, as large as eye stalk. Antennules sexually dimorphic (Figs. 11 g, h); male peduncle with first segment as long as or slightly longer than combined length of distal 2 segments, armed laterally with several long inwardly curving setae (somewhat deformed in figure due to artifact); second segment shortest, wider than long; third segment stout, as long as wide, no short hooked setae observed on mesial margin but with several long ordinary setae around disto-mesial part, lateral flagellum basally swollen, forming male lobe hirsutid with dense long hair. Antennule in females more slender than that of males, first segment of peduncle as long as or slightly longer than combined length of distal 2 segments, with several long inwardly curving setae on lateral margin; second segment shortest, slightly wider than long; third segment longer than wide, with several long setae on disto-mesial part. Antenna (Fig. 11 i) with scale extending well beyond end of antennular peduncle, about 7 times as long as wide, disto-lateral spine extending well beyond end of blade, distal suture present; sympod with two long spines at disto-mesial part, mesial second spine slightly longer than most mesial one, accompanying 0���2 short spines at base of longest spine. Labrum (Fig. 11 j) truncated anteriorly, without median spine. Mouth parts as illustrated (Figs. 12 a���e). Thoracic appendages (Figs. 12 f���h) remarkable in having proportionately long endopods particularly in seventh one; third thoracic endopod slightly stouter than fourth one, carpo-propodus 3 -segmented, basal article nearly twice as long as combined length of distal 2 segments; fourth to sixth endopods similar in shape but length increasing posteriorly, its carpo-propodi divided into 3���5 segments; seventh thoracic endopod longest, and male endopod normally reaching end of antennular peduncle, slightly shorter in female extending to end of cornea, carpo-propodus with 5 or 6 articles, basal article noticeably long, as long as combined length of remaining distal articles or slightly longer, long disto-ventral setae nearly smooth, without stout setules. Rudimentary endopod of eighth thoracic limb in males (Fig. 12 i) normally 3 -segmented, falling short of end of basal plate of exopod when extended; second segment with several long setae (not shown due to damage); third segment elongated, rod-shaped. Rudimentary endopod of eighth thoracic limb in females (Fig. 12 j) un-articulated, falling slightly short of end of basal plate of exopod, with short seta near mid-length and slightly longer sub-terminal seta. Abdomen (Fig. 11 a) smooth, first to fifth somites sub-equal in length, sixth somite 1.3���1.55 times as long as fifth one; first somite in male ventrally rounded to form pleuron with shallow excavation on anterior part. Pleopods in males biramous (Figs. 13 a���d); first pleopod with endopod un-articulated, bearing several short marginal setae, exopod multi-articulated; exopod of second pleopod elongated, nearly reaching mid-length of sixth abdominal somite, composed of approximately 15 articles, basal 6 articles each with long seta and distal article with pair of apical setae and proportionately long sub-apical seta, but several unarmed articles present between these armed articles; endopod multi-articulated; third to fifth pleopods similar in shape, with multi-articulated endopods and exopods of sub-equal length. Pleopods in females (Figs. 13 e���g) un-articulated, generally increasing in length on posterior somites while third one relatively short, as long as first one. Uropod (Fig. 11 f) 2 -segmented in both exopod and endopod, exopod narrow and slender, distal segment about half-length of basal segment; endopod barely reaching or falling slightly short of mid-length of distal segment of exopod, with stout ventral seta around basal one-third. Telson (Figs. 11 e, 13 h, i) 1.3���1.4 times as long as sixth abdominal somite, distal margin (excluding posterior spinose setae) reaching articulation of uropodal endopod, comparatively narrow in general appearance, slightly more than 3 times as long as basal width and again about 4 times as long as broad at sub-basal constriction part, forming no discernible waist but having nearly parallel lateral margins; rounded posterior margin with 2 pairs of large spinose setae of sub-equal length, each with setules becoming broad towards distal; lateral margin of telson armed with 9���12, commonly 10 or 11, very stout, smooth setae on posteriorl two-thirds, spaciously set posteriorly and posterior setae distinctly longer than posterior width of telson proper. Body length. Largest male: BL ca. 15 mm, largest ovigerous female: BL ca. 16 mm. Etymology. The species name ��� armiger ��� (armed in Latin) reflects the characteristic ornamentation of the telson, alluding to an armature-like structure. Remarks. Rhopalophthalmus armiger sp. nov. was regarded to be different from its closest relative, R. longipes, in the structure of the telson, a proportionately long seventh thoracic endopod, as well as a comparatively large eyes (further details can be found in ���Remarks��� under R. longipes). Rhopalophthalmus macropsis collected from the Indian Ocean (Pillai 1964, 1965, 1973) has occasionally been regarded as a synonym of R. longipes (Wang & Liu 1994; Liu & Wang 2000). We could not examine the type specimen of R. macropsis despite our attempts to secure permission from the Indian institutions. However, the type of R. macropsis collected from the Arabian Sea appeared to be completely different from R. longipes as well as from its variant in having 1) the lateral pair of the spinose apical telson setae distinctly longer than the mesial pair (subequal length in R. longipes and R. armiger), 2) the vestigial male endopod of the eighth thoracic limb greatly elongated, overreaching basal plate of the exopod (falling distinctively short of the end of basal plate in R. longipes and R. armiger), and 3) the carpo-propodus of the seventh thoracic endopod with the basal segment of sub-equal length to the combined length of the remaining distal articles (distinctly longer in R. longipes and R. armiger). Meanwhile, a young male reported from the Malacca Strait under the name R. macropsis by Pillai (1973) does not conform to the type of R. macropsis, but agrees with a variant of R. longipes reported by Ii (1964). As Pillai (1964) remarked in his original description, R. macropsis seemed to show a similarity to R. kempi O.Tattersall, 1957 or R. orientalis O. Tattersall, 1957 rather than to R. longipes or its variant, which further justifies reassigning the Pillai (1973) male from R. macropsis to the new species R. armiger. Unfortunately, we could not access the Chinese material; however, it is probable that some specimens recorded under R. longipes from the South China Sea are R. armiger, as some of them are remarked to have fewer telson setae than the typical R. longipes. Also, a juvenile specimen recorded from off the north-east coast of Australia under the name R. egregius by Tattersall (1936) would belong to the new species for its characteristic feature of the telson (see Fig. 13 i). Rhopalophthalmus armiger shows a resemblance to R. terranatalis O. Tattersall, 1957 collected from Africa, but the latter species has the carpo-propodus of the seventh thoracic endopod composed of seven sub-segments opposed to four sub-segments with an unusually elongated carpus in the new species. Rhopalophthalmus armiger, together with its closest relative, R. longipes, is remarkable among the Asian members of Rhopalophthalmus in having no hooked setae on the male antennular peduncle as well as a proportionately short third pleopod in females, which suggests that these features may have phylogenetic significance. Distribution. This species may be an oceanic form of tropical waters and was captured from the South China Sea, Timor Sea, north-eastern Australia, and the Malacca Strait (Ii 1964; Pillai 1973; Wang & Liu 1994; Liu & Wang 2000; present study)., Published as part of Hanamura, Yukio, Murano, Masaaki & Man, Alias, 2011, Review of eastern Asian species of the mysid genus Rhopalophthalmus Illig, 1906 (Crustacea, Mysida) with descriptions of three new species, pp. 1-37 in Zootaxa 2788 on pages 18-23, DOI: 10.5281/zenodo.207815, {"references":["Ii, N. (1964) Mysidae. Fauna Japonica. Biogeographical Society of Japan, Tokyo. 610 pp.","Wang, S. & Liu, J. Y. (1994) A faunal study of Mysidacea of Nansha Islands and adjacent waters. Marine Fauna and Flora and Biogeography of the Nansha Islands and Neighbouring Waters I. Ocean Press, pp. 61 - 111. (in Chinese)","Liu, R. & Wang, S. (2000) Order Mysidacea (Arthropoda Crustacea Malacostraca). Fauna Sinica. Science Press, Beijing, 326 pp. (in Chinese)","Tattersall, W. M. (1936) Mysidacea and Euphausiacea. Scientific Reports of the Great Barrier Reef Expedition, 1928 - 1929, 5, 143 - 176.","Pillai, N. K. (1973) Mysidacea of the Indian Ocean. IOBC Handbook to the International Zooplankton Collections, Indian Ocean Biological Centre, 4, 1 - 125.","Pillai, N. K. (1964) Report on the Mysidacea in the collections of the Central Marine Fisheries Research Institute, Mandapam Camp, south India-Part I. Journal of the Marine Biological Association of India, 6, 1 - 41.","Pillai, N. K. (1965) A review of the work on the shallow water Mysidacea of the Indian waters. Proceedings of Symposium on Crustacea, Marine Biological Association of India, 5, 1681 - 1728.","Tattersall, O. S. (1957) Report on a small collection of Mysidacea from the Sierra Leone Estuary together with a survey of the genus Rhopalophthalmus Illig and a description of a new species of Tenagomysis from Lagos, Nigeria. Proceedings of the Zoological Society of London, 129, 81 - 128."]}

Rhopalophthalmus longipes Ii, 1964 (Figs. 8���10) Rhopalophthalmus longipes Ii, 1964: 180, figs. 46, 47 (in part, not Fig. 47 n = R. armiger sp. nov.). ��� Wang & Liu 1994: 91, fig. 14 (?in part). ��� Wang & Liu 1997: 204. ��� Liu & Wang 2000: 114, fig. 27 (?in part). Material examined. Syntypes. Ajiro, Shizuoka Prefecture, Japan: 63 males (BL 6.3 ���ca. 9.5 mm), 75 females (BL ca. 6.5���9.5 mm), 51 juvs. (BL ca. 4.5���6.2 mm) (more or less damaged); 11 Sept 1935, coll. H. Aikawa (No. 217 in Ii, 1964) (NSMT Cr 21219). Japan. Off Amami Is., south-western Japan: 1 female (BL 6.2 mm); RV Tansei-maru cruise KT- 70 - 2, St. 451, 28�� 10.3 ' N, 129 �� 13.8 ' E, 13: 53 ��� 14: 13, bottom net, 67���68 m depth, 24 Apr 1970, coll. M. Murano (NSMT Cr 21220). ��� Near mouth of Ohmura Bay, Nagasaki Prefecture: 3 males (BL ca. 7.5 ���10 mm) (more or less damaged); sledge, 30 Sept 1977, coll. T. Takita (NSMT Cr 21221). South China Sea. South-western part of South China Sea: 1 male (BL ca. 7 mm); RV Hakuho-maru cruise KH- 72 - 1, St. 45, 05�� 13.5 ' N, 107 ��00.8' E to 05�� 13.7 ' E, 107 ��01.1' E, plankton net installed at mouth of 3 m beam trawl, 60 m depth, 10 July 1972, coll. M. Murano (NSMT Cr 21223). Timor Sea. Western part of Timor Sea: 27 males (BL ca. 5.5 ���8.0 mm), 15 females (BL ca. 5.5 ���8.0 mm), 18 juvs. (BL ca. 4.5���6.5 mm) + abdomens; RV Hakuho-maru cruise KH- 72 - 1, St. 32, 12�� 37.3 ' S, 124 �� 33.9 ' E to 12 ��36.0'S, 124 �� 36.4 ' E, plankton net installed at mouth of 3 m beam trawl, 74���78 m depth, 25���26 June 1972, coll. M. Murano (NSMT Cr 21224). Description. Body moderately stout (although majority of material examined were more or less damaged). Anterior dorsal part of carapace between postorbital spines slightly produced, forming evenly rounded rostral plate (Figs. 8 a���d); postorbital spine sharp, supported by very short, feebly defined carina; cervical sulcus well marked dorsally and laterally around anterior one-third, small but distinct nodule present just posterior to cervical groove in addition to posterior one; posterior dorsal margin excavate, leaving last 3 thoracic somites uncovered in dorsal view; cheeks concave or slightly sinuous; antero-lateral spine moderately large. Eyes (Figs. 8 b���d, 10 a, b) somewhat globular, falling short of end of second segment of antennular peduncle, cornea well pigmented and developed among Asian members of genus and slightly shorter than eye stalk. Antennules sexually dimorphic (Figs. 8 g, h); male antennular peduncle with first segment distinctly longer than combined length of distal 2 segments, with several long, inwardly curving setae along lateral margin (slightly deformed in figure due to artifact); second segment shortest, shorter than wide; third segment stout, as long as wide, so far no short hooked setae observed but with several long ordinary setae around mesial and disto-mesial parts, lateral flagellum basally swollen, forming male lobe, hirsutid with dense long hair. Female antennular peduncule slightly more slender than that of males, first segment distinctly longer than combined length of distal 2 segments, with several long inwardly curving setae along lateral margins (slightly deformed in figure due to artifact); second segment shortest, slightly shorter than wide; third segment longer than wide, with several long setae around distomesial part. Antenna (Figs. 8 i, j, 10 e) with scale extending well beyond end of antennular peduncle, about 7 times as long as wide, disto-lateral spine extending well beyond end of lamella, distal suture present; sympod spines composed of 2 stout spines, lateral spine longer than most mesial one, and also 1 or 2 short lateral spines near base of longest spine. Mandibular palp (Fig. 9 a) with distal segment sub-oval, with rather long setae along margins (other mouth parts, see Ii, 1964: figs. 46 f, g, 47 c���f). Thoracic appendages (Figs. 9 b���f, 10 d) remarkable in having proportionately long endopods particularly in seventh one; third thoracic endopod slightly stouter than fourth one, carpo-propodus 2 - or 3 -segmented, basal article sub-equal in length to combined length of distal 2 segments; fourth to sixth endopods similar in shape but length increasing posteriorly, its carpo-propodi divided into 3 or 4 articles; seventh endopod longest, fully reaching mid-length of cornea, carpo-propodus with 4 articles, basal one noticeably long, as long as or longer than combined length of second and third articles, longest disto-ventral setae rather smooth, without stout setules. Rudimentary endopod of eighth thoracic limb in males (Figs. 9 g, 10 f) normally 3 -segmented, reaching mid-length of basal plate of exopod, with several long setae on second articles and a few short setae on lateral part of distal article. Rudimentary endopod of eighth thoracic limb in females (Fig. 9 h) normally un-articulated, barely reaching mid-length of basal plate of exopod. Abdominal somites smooth, first to fifth somites sub-equal in length, sixth somite about 1.2 times as long as fifth one; first somite of male rounded ventrally to form pleuron with shallow excavation at anterior part. Pleopods in males (Fig. 9 i) biramous; exopod of second pleopod elongated, composed of about 15 articles, several basal articles accompanying long seta, distal articles without seta except for most distal one, latter with pair of apical setae and proportionately long sub-apical seta. Pleopods in females (Figs. 9 j���l) un-articulated, length generally increasing on posterior somites but that on third pleopod somewhat short, comparable to first one. Uropod (Fig. 8 f) 2 -segmented in both exopod and endopod, exopod narrow and slender, distal segment about half-length of basal segment; endopod barely reaching mid-length of distal segment of exopod, with stout seta on ventral surface around basal one-third, distal segment about one-third length of basal segment. Telson (Figs. 8 e, 9m, 10 c) about 1.3 times as long as sixth abdominal somite, distal margin (excluding spinose apical setae) reaching articulation of uropodal endopod, comparatively narrow, about 3.5 times as long as basal width and again slightly more than 4.5 times as long as wide at sub-basal constriction part, abruptly narrowing near base but not forming discernible waist owing to sub-parallel lateral margins above mid-length, and then gently narrowing towards distal; posterior margin of telson with 2 pairs of spinose setae of sub-equal length, each with setules becoming broader towards distal; lateral margin of telson armed with 14���16 somewhat closely set, moderately long smooth setae on distal two-thirds, increasing in length posteriorly, posterior setae of lateral series as long as posterior width of telson. Body length. Largest recorded male: BL ca. 10 mm, ovigerous female not collected so far. Remarks. Rhopalophthalmus longipes was established by Ii (1964) on the basis of specimens collected mainly from Japan. Due to the somewhat poor condition of the specimens, Ii left the presence/absence of dorsal nodules on the carapace undetermined. The specimens available to us including the syntypes were more or less damaged as already mentioned by Ii, although a few specimens were found to possess a small nodule just posterior to the cervical sulcus (cf. Figs. 8 a, 10 a); hence we believe that this species possesses this nodule. Ii (1964) noted that some specimens from the South China Sea have fewer but remarkably greater setae on the lateral margins of the telson as compared with the typical form of R. longipes, and he provisionally dealt with them as a variation of this species. This variety has subsequently been a subject of taxonomic arguments among mysid researchers (Pillai 1973; Liu & Wang 2000). We were able to examine a considerable number of specimens, covering various size ranges, with this characteristic feature in their telson. In those examined so far, the number of lateral telson setae of the variety is noticeably fewer when compared with that of the typical form throughout the entire life stage, and, even in larger specimens exceeding BL 10 mm, the setal counts are within the range of 9���12 as opposed to 14���16 in the typical form of BL 8���12 mm. Moreover, these telson setae of the former specimens are much greater than those in the typical R. longipes as posterior setae in adult specimens are noticeably longer than the posterior telson width relative to the sub-equal length in the typical specimens. The endopod of the seventh thoracopod is proportionately long in the variant, fully reaching the end of the antennular peduncle even in sub-adult males, while in typical R. longipes, it barely reaches the end of the cornea. Furthermore, the eyes of the variety appear to be larger than those of the typical R. longipes, being as large as the second segment of the eye stalk relative to those of slightly smaller eyes. Thus, we concluded that both populations are different at the species level. Meanwhile, Pillai (1964) recorded R. macropsis on the basis of a male specimen collected from the Arabian Sea and later an immature male of this species was reported from the Malacca Strait (Pillai 1973). The identity of R. macropsis has remained disputed as several researchers have regarded it to be a valid species (Mauchline & Murano 1977; Mauchline 1980; Vilas-Fern��ndez et al. 2008) while Chinese taxonomists considered it to be the morphologically variable R. longipes (Wang & Liu 1994; Liu & Wang 2000). In this study, we reached the conclusion that R. macropsis is a valid species, although the eastern Indian Ocean specimen examined by Pillai (1973) might be different from his Arabian Sea species. The identity and taxonomic position of Pillai���s specimens is discussed in ���Remarks��� under R. armiger sp. nov. Rhopalophthalmus longipes shows resemblance to R. terranatalis O. Tattersall, 1957 collected from Africa, but the latter species has the carpo-propodus of the seventh thoracic endopod composed of seven sub-segments instead of four sub-segments with an unusually elongated carpus in R. longipes. Distribution. Recorded with certainty from Japanese coastal waters, South China Sea, and Timor Sea (Ii 1964; present study)., Published as part of Hanamura, Yukio, Murano, Masaaki & Man, Alias, 2011, Review of eastern Asian species of the mysid genus Rhopalophthalmus Illig, 1906 (Crustacea, Mysida) with descriptions of three new species, pp. 1-37 in Zootaxa 2788 on pages 14-18, DOI: 10.5281/zenodo.207815, {"references":["Ii, N. (1964) Mysidae. Fauna Japonica. Biogeographical Society of Japan, Tokyo. 610 pp.","Wang, S. & Liu, J. Y. (1994) A faunal study of Mysidacea of Nansha Islands and adjacent waters. Marine Fauna and Flora and Biogeography of the Nansha Islands and Neighbouring Waters I. Ocean Press, pp. 61 - 111. (in Chinese)","Wang, S. & Liu, J. Y. (1997) Mysidacea fauna of the East China Sea. Studia Marina Sinica, 38, 191 - 222. (in Chinese)","Liu, R. & Wang, S. (2000) Order Mysidacea (Arthropoda Crustacea Malacostraca). Fauna Sinica. Science Press, Beijing, 326 pp. (in Chinese)","Pillai, N. K. (1973) Mysidacea of the Indian Ocean. IOBC Handbook to the International Zooplankton Collections, Indian Ocean Biological Centre, 4, 1 - 125.","Pillai, N. K. (1964) Report on the Mysidacea in the collections of the Central Marine Fisheries Research Institute, Mandapam Camp, south India-Part I. Journal of the Marine Biological Association of India, 6, 1 - 41.","Mauchline, J. & Murano, M. (1977) World list of the Mysidacea, Crustacea. Journal of the Tokyo University of Fisheries, 64, 39 - 88.","Mauchline, J. (1980) The biology of mysids and euphausiids. Advances in Marine Biology, 18, 1 - 681.","Vilas-Fernandez, C., Drake, P. & Sorbe, J. C. (2008) Rhopalophthalmus tartessicus sp. nov. (Crustacea: Mysidacea), a new mysid species from Guadalquivir estuary (SW Spain). Organisms Diversity and Evolution, 7, 292 e 1 - 292 e 13.","Tattersall, O. S. (1957) Report on a small collection of Mysidacea from the Sierra Leone Estuary together with a survey of the genus Rhopalophthalmus Illig and a description of a new species of Tenagomysis from Lagos, Nigeria. Proceedings of the Zoological Society of London, 129, 81 - 128."]}

Macrobrachium eriocheirum Dai, 1984 (Fig. 6) Macrobrachium eriocheirum Dai, 1984: 247, fig. 13; Cai & Dai 1999: 230, fig. 13; Cai et al. 2004: 628, fig. 18 a���d. Macrobrachium dienbienphuense: Li et al. 2007: 84 (part). Material examined. Luang Praban Province: Ou River, Ngoi District, 7 males (CL 9.8���13.3 mm), 2 females (CL 9.8 mm, 10.1 mm), Sept 2000, coll. O. Lasasimma (ex LARReC C 0002); Ou River, Ngoi District, 2 males (CL 12.0 mm, 15.0 mm), Feb 2001, coll. O. Lasasimma (ex LARReC C 0004); Ou River, Ngoi District, 3 males (CL 12.5���13.8 mm), Feb 2001, coll. O. Lasasimma (ex LARReC C 0006); Ou River, Ngoi District, 3 males (CL 13.5��� 15.8 mm), 5 ovig. females (CL 10.5 ���13.0 mm), Feb 2001, coll. O. Lasasimma (LARReC C 0007); Ou River, Ngoi District, 1 male (CL 13.5 mm), 1 female (CL 11.4 mm), 4 ovig. females (CL 9.8���12.2 mm), Feb 2001, coll. O. Lasasimma (LARReC C 0009); Xuang River, Na Pho Village, St. 2, 10 males (CL 6.2���15.2 mm), 28 females (CL 5.8���11.1 mm), 28 Jan 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 1, 1 males (CL 11.0 mm), 27 Mar 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 3, 2 males (CL 13.0 mm, 14.0 mm), 27 Mar 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 2, 2 males (CL 12.7 mm, 15.2 mm), 1 ovig. female (CL 10.3 mm), 27 Apr 2008, hand net, coll. S. Ito et al. Savannakhet Province: Sampling details unknown, 8 males (CL 10.5���12.1 mm), 1 female (CL 10.2 mm), 5 females (CL 7.8���11.2 mm), 2002; Kae Stream, 6 males (CL 11.5���15.7 mm), other details unknown. Champasak Province: Khone Island, 1 male (CL 12.7 mm), 11 July 2009, set net, coll. S. Ito & Y. Niimura. Diagnosis. Rostrum (Fig. 6 a) reaching or slightly overreaching end of antennal scale, 0.4���0.6 times as long as carapace, dorsal margin weakly convex, directed slightly ventrad, armed dorsally with 11���14 teeth including 4���6 placed posterior to orbital margin, ventral margin with 2 or 3 teeth; antennal lobe moderately produced, antennal spine slightly extending beyond antennal lobe; hepatic spine as large as or slightly smaller than antennal spine, situated posteriorly, distinctly below level of antennal tooth. Abdomen (Fig. 6 a) with sixth somite 1.2���1.5 times as long as fifth; pre-anal carina well developed; fourth pleuron rounded posteroventrally, that of fifth angulated. Telson 1.38 times as long as sixth somite, with sub-triangular posterior end, with pairs of ordinal small and long sub-distal spines and 2 pairs of dorsolateral spines, anterior pair of latter spines placed at or just posterior to mid-length. Antennal scale 0.5���0.6 times as long as carapace, slightly more than 2.5 times longer than wide. Epistome usually with marked anteromedian projection (tri-lobed in form) but rarely indistinct. Third maxilliped falling well short of anterior end of antennular peduncle, distal segment slightly shorter than penultimate. First pereopod extending beyond antennal scale by distal 0.3���0.5 length of carpus and onwards, fingers as long as or slightly shorter than palm. Second pereopods (Fig. 6 a���c) distinctly unequal in length, covered with long, dense velvety setae normally on palm and fingers: major leg longer than total body length, extending beyond antennal scale by carpus and onwards; merus as long as palm, 2.9���3.9 times as long as high, with microscopically small spinules particularly on dorsal and lateral surfaces; carpus somewhat cup-shaped, normally less than 2.0 times as long as high, with minute spinules particularly on lateral and dorsal surfaces; palm as long as or slightly shorter than fingers, 2.2���2.8 times as long as wide; fingers with narrow gape when crossed, with 11���17 teeth on cutting edges; minor leg extending beyond antennal scale by chela, palm slightly more than 1.5 times as long as fingers and again slightly more than 2 times as long as wide. Third pereopod with propodus (Fig. 6 d) 2.3���2.9 times as long as dactylus, with 5 or 6 sparsely placed spines on posterior margin. Appendix masculina (Fig. 6 e) about twice length of appendix interna, with numerous stiff setae on mesial surface as well as anterolateral margin. Uropodal exopod (Fig. 6 f) sub-equal in length to endopod, movable spine on diaeresis shorter than lateral projection. Egg. Eggs fewer in number but large in size, non-eyed eggs measuring 1.0��� 1.25 x 1.4���1.7 mm. Remarks. As has been mentioned above, the exact identification of species of the ��� M. dienbienphuense ��� group has often been difficult using just morphology, especially in immature and female specimens due to intra-specific variations and ontogenetic morphological changes, the measurements and comparison data in fully grown specimens assigned to M. eriocheirum, M. amplimanus, and M. dienbienphuense were summarised in Table 2, and they suggest all three are distinct. Furthermore, M. eriocheirum appeared to bear proportionately larger eggs than those of the two congeners. The morphological data were supported by the mitochondrial gene (16 S rRNA) analysis, as it yielded three clearly different clades that could be regarded as the three distinct species (Fig. 5), although the M. eriocheirum clade has genetically high intra-specific divergences. In our personal examination, 42 % of Laotian specimens (N= 78) were right-handed, with the right second pereopod being larger than the left one (Hanamura et al. unpubl. data). Distribution. Yunnan Province, south-western China, Thailand, and Laos (Dai 1984; Cai & Dai 1999, Cai et al. 2004; present study). Macrobrachium eriocheirum appeared to be one of the most abundant species along the Mekong River system in Laos., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 10-11, DOI: 10.5281/zenodo.204065, {"references":["Dai, A. Y. (1984) A preliminary study on the freshwater prawn genus Macrobrachium of China (Decapoda, Caridea). Acta Zootaxonomica Sinica, 9, 244 - 252. (in Chinese)","Li, X., Liu, R., Liang, X. & Chen, G. (2007) Crustacea, Decapoda, Palaemonidea. Fauna Sinica, Invertebrate, vol. 44. Science Press, Beijing, 381 pp. (in Chinese)"]}

Rhopalophthalmus philippinensis Hanamura & Murano sp. nov. (Figs. 18���21) Material examined. Holotype. Philippines. Banica, Panay Is.: male (BL ca. 11 mm); 15 Aug 1976, 2:00 p.m., coll. SEAFDEC (NSMT Cr 21244). Paratypes. Philippines. Banica, Panay Is.: 16 males (BL ca. 8���11.5 mm), 1 male abdomen, 1 female (BL 8.5 mm), 1 ovig. female (BL ca. 12 mm); data same as holotype (NSMT Cr 21245). Additional material examined. Philippines. Banica, Panay Is.: 5 males (BL ca. 10.5 ���ca. 11 mm), 3 females (BL ca. 10���11 mm), 6 ovig. females (BL ca. 10.5���12.5 mm); 27 Aug 1976, 9: 30 a.m., coll. SEAFDEC (NSMT Cr 21246). ��� 8 males (BL ca. 7.0��� 10.5 mm), 1 female (BL 12.0 mm), 5 ovig. females (BL ca. 10.3���11 mm); 28 Aug 1976, 10:00 a.m., coll. SEAFDEC (NSMT Cr 21247). ��� Mouth of Altavas River, Banga Bay, Panay Is.: 2 males (BL 7.5, 8.5 mm), 8 females (BL 7.5���9.5 mm), 1 ovig. female (BL 10.2 mm), 1 juv. (BL 4.0 mm); plankton net, 1��� 2 m depth, 2 Dec 1979, coll. M. Murano (NSMT Cr 21248). South China Sea. Southern part of South China Sea: 1 male (BL 9.5 mm), 21 females (BL 7.5���11.6 mm), 62 ovig. females (BL 9.5���11.7 mm), 1 juv. (BL ca. 5.5 mm); RV Hakuho-maru cruise KH- 72 - 1, St. 45, 05�� 13.5 ' N, 107 ��00.8' E to 05�� 13.7 ' N, 107 ��01.1' E, plankton net installed at mouth of 3 m beam trawl, 60 m depth, 10 July 1972, coll. M. Murano (NSMT Cr 21249). Description. Body moderately stout (Fig. 18 a). Anterior dorsal part of carapace between postorbital spines slightly produced and anterior margin weakly convex, forming wide, rounded rostral plate (Figs. 18 a���d); postorbital spine sharp, supported by short carina; cervical groove marked dorsally and laterally around anterior one-third of carapace; anterior dorsal median nodule not present or occasionally represented by very feeble swelling just posterior to cervical sulcus, posterior nodule well protruded near posterior end; posterior dorsal margin excavate, leaving last 3 thoracic sometimes uncovered in dorsal view; cheeks evenly concave; antero-lateral spine sharp, extending as far as end of rostral plate. Eyes (Figs. 18 a���d) sub-pyriform, reaching second segment of antennular peduncle; cornea about two-thirds length of eye stalk. Antennules sexually dimorphic (Figs. 18 f, g); male peduncle with first segment slightly longer than combined length of second and third segments, armed laterally with several long inwardly curving setae (slightly deformed in figure due to artifact); second segment shortest, shorter than its width; third segment as long as wide, with a few short hooked setae on mesial margin and several long ordinary setae around disto-mesial part, lateral flagellum basally swollen, forming male lobe furnished with dense slender hair. Female antennular peduncle more slender than that of males, first segment longer than combined length of second and third segments, armed with several long inwardly curving setae along mesial margin (somewhat deformed in figure due to artifact); second segment shortest, shorter than its width; third segment as long as or slightly longer than its width. Antenna (Fig. 19 b) with scale extending well beyond antennular peduncle, about 6���7 times as long as wide, disto-lateral spine well advanced, overreaching anterior end of lamella; distal suture present; sympod with mesial second spine longest and considerably longer than most mesial one, and also 5���7 small lateral spines. Labrum (Fig. 19 c) truncated anteriorly, without median spine. Mouth parts as illustrated (Figs. 19 d���h). Thoracic appendages: endopod of third thoracopod (Figs. 19 i, j) sub-equal in length to fourth one but slightly stouter than latter, carpo-propodus composed of 5���7 articles; fourth to sixth thracopod with endopods (Figs. 20 a, b) similar in shape, extending to ocular peduncle, carpo-propodi composed of 7���9 articles; seventh thoracopod with endopod (Figs. 20 c, d) reaching eye stalk, carpo-propodus with 8���10 articles, each with longest disto-ventral seta rather smooth, without marked setules around mid-length. Vestigial endopod of eighth thoracopod in males (Fig. 20 e) composed normally of 3 articles, falling slightly short of end of basal plate; second article bearing several long setae; third article elongated, possessing short sub-distal seta. Vestigial endopod of eighth thoracopods in females (Fig. 20 f) un-articulated, extending as far as or slightly beyond end of basal plate of exopod, with or without short seta at mid-length. Abdomen (Fig. 18 a) smooth, without any ornamentation, first 5 somites sub-equal in length; sixth somite 1.25���1.45 times as long as fifth one; first somite in male rounded ventrally to form pleuron with shallow excavation near anterior part. Pleopods in males (Figs. 21 a���d) biramous: first pleopod with endopod un-articulated, possessing several short marginal setae, exopod multi-articulated; exopod of second pleopod greatly elongated, reaching or slightly overreaching mid-length of sixth abdominal somite, composed of about 13 articles, distal segment with pair of apical setae and proportionately long sub-apical seta, several basal articles with long seta while several unarmed articles present between these armed articles, endopod multi-articulated; third to fifth pleopods similar in shape, with multi-articulated endopods and exopods of sub-equal length, their length slightly decreasing posteriorly. Pleopods in females (Figs. 21 e���g) un-articulated, length increasing on posterior somites. Uropod (Fig. 19 a) 2 -segmented in both exopod and endopod, exopod with distal segment about half-length of basal one; endopod reaching around mid-length of distal segment of exopod, several scattered short setae along lateral margin, distal segment about two-fifths length of basal one, latter with stout seta on ventral surface near midlength. Telson (Fig. 18 e) sub-equal in length to sixth abdominal somite, falling far short of articulation of uropodal endopod, about twice as long as basal width and again about 3 times as long as broad at sub-basal constricted part, widest at basal part and abruptly narrowing near base, forming no discernible waist owing to parallel lateral margins, then gradually narrowing from mid-length toward distal; rounded posterior end of telson with 2 pairs of spinose setae, lateral pair distinctly longer than mesial pair, each with rather sharp setules throughout margins; lateral margin of telson armed with somewhat short 7���9, commonly 8, setae on posterior half, most of them possessing a few to several setules on posterior margin. Body length. Largest recorded male: BL 11.5 mm, largest female: BL 12.5 mm. Egg size. Stage I embryos (eggs) oblong, 0.70���0.90 mm along longest axis (N= 3). Etymology. The name of the species ��� philippinensis ��� is selected for the type locality. Remarks. Rhopalophthalmus philippinensis is remarkable in the genus in having 1) a proportionately short telson without a discernible waist, 2) a unique spine arrangement on the antennal sympod armed with the longest mesial second spine flanked by a shorter most mesial spine in addition to 5���7 much short lateral spines, and 3) the carpo-propodus articles of the third to seventh thoracic endopods are also larger in number than those of other members of eastern Asian Rhopalophthalmus. The general appearance of R. philippinensis shows some resemblance to that of R. africana O. Tattersall, 1957 captured from the Sierra Leone estuary, western Africa, but the African species possesses a single prominent spine and a single small spine on the antennal sympod instead of having several small spines in R. philippinensis. Furthermore, the carpo-propodi of the third to seventh thoracic endopods are composed of four sub-segments in R. africana as opposed to five or more in the new species. The new species also resembles R. dakini O. Tattersall, 1957 from Australia, but the antennal sympod spines of Australian species are arranged to form a perfect cone. Distribution. Recorded from the Philippines and southern part of South China Sea (present study)., Published as part of Hanamura, Yukio, Murano, Masaaki & Man, Alias, 2011, Review of eastern Asian species of the mysid genus Rhopalophthalmus Illig, 1906 (Crustacea, Mysida) with descriptions of three new species, pp. 1-37 in Zootaxa 2788 on pages 29-34, DOI: 10.5281/zenodo.207815, {"references":["Tattersall, O. S. (1957) Report on a small collection of Mysidacea from the Sierra Leone Estuary together with a survey of the genus Rhopalophthalmus Illig and a description of a new species of Tenagomysis from Lagos, Nigeria. Proceedings of the Zoological Society of London, 129, 81 - 128."]}

Macrobrachium niphanae Shokita & Takeda, 1989 (Fig. 9) Macrobrachium niphanae Shokita & Takeda, 1989: 147, figs. 1, 2, pl. 1; Cai et al. 2004: 609. Macrobrachium secamanense Dang, 1998: 1, fig. 1. Material examined. Vientiane Capital: Nong Niew Market, 1 male (CL 11.0 mm), 30 Aug 2007, coll. H. Ikenoue. Khammouane Province: Theun River, 1 female (CL 10.8 mm), 13 July, 2009, hand net, coll. Ito et al. Champasak Province: Khone Island, 1 male (CL 8.5 mm), 5 females (CL 5.3–8.2 mm), 3 ovig. females (CL 7.0– 8.5 mm), 1 juv. (CL 4.3 mm), set net, 10 July 2009, coll. S. Ito & Y. Niimura; Det Island, 2 males (CL 7.4 mm, 10.4 mm), 21 July 2009, set net, coll. Y. Niimura; Det Is., 1 male (CL 12.0 mm), 21 July 2009, set net, coll. Y. Niimura. Diagnosis. Rostrum (Fig. 9 a) barely reaching anterior end of antennal scale, weakly curving dorsad, dorsal margin with somewhat widely spaced 8–10 teeth, including 1–3 placed posterior to orbital margin, ventral margin with 3 or 4 teeth; antennal spine sub-marginal, apex barely reaching end of antennal lobe and antennal spine supported by moderately long carina extending backward to near hepatic spine, latter situated at approximately same level of antennal spine. Sixth abdominal somite 1.4–1.6 times as long as fifth; pre-anal carina well marked as elevated thin carina. Telson 1.4–1.8 times as long as sixth abdominal somite, posterior margin sub-triangular with 2 pairs of ordinary subterminal spines, 2 pairs of dorsolateral spines, anterior pair of latter spines situated on mid-length of telson. Antennal scale 0.7–0.75 times as long as carapace, 3.0– 3.5 times as long as wide. Epistome composed of 2 lobes with shallow transverse median groove. Second pereopods (Fig. 9 a–c) almost equal in length, slightly longer than total body length, extending beyond antennal scale by four-fifths of carpus and onwards, ischium, merus, carpus, and propodus covered with short velvety setae; carpus slightly longer than merus and again slightly longer than palm; fingers 0.65–0.70 times as long as palm, with 18–20 tuberculate teeth on entire margin of cutting edges. Third pereopod (Fig. 9 d, e) with propodus 3.2–3.8 times as long as dactylus. Appendix masculina (Fig. 9 f) about twice length of appendix interna, with moderately long setae along anterolateral margin as well as mesial surface. Exopod of uropod slightly longer than endopod, movable spine on diaeresis (Fig. 9 g) slightly longer than lateral projection. Egg. Eggs small in numbers and moderately large in size, measuring 1.0– 1.1 x 1.4–1.5 mm. Remarks. The present specimens basically agreed with the original description by Shokita &Takeda (1989), although some minor differences were found. Our specimens have comparatively fewer teeth on the cutting edges of the second pereopod (see also Cai et al. 2004). The second pereopod of our specimens collected from the Khammouane and Champasak Provinces was found to have velvety setae on the carpus, while, in other specimens, the merus is nearly naked or occasionally with such setae only on its anterior part. These are regarded as intraspecific variations. Cai et al. (2004) suggested that M. secamanense Dang, 1998, reported from the southern part of Laos, could be a junior synonym of this species. Distribution. Thailand and southern and central Laos (Cai et al. 2004; present study).

Macrobrachium sp. (Fig. 19) Material examined. Vientiane Capital: Phatthana Village, 1 male (CL 11.0 mm), 22 Dec 2007, coll. school children & H. Ikenoue. Diagnosis. Rostrum (Fig. 19 a, tip broken) nearly straight, reaching anterior end of antennal scale, armed dorsally with 8 teeth, including 2 situated clearly posterior to orbital margin, ventral margin with 3 teeth; antennal spine arising just behind lateral margin, apex extending as far as end of antennal lobe; hepatic spine as large as antennal spine, placed posteriorly, just below level of antennal spine. Sixth abdominal somite 1.54 times as long as fifth, pre-anal carina distinct, sub-triangular. Telson as long as sixth abdominal somite, posterior end triangular, with moderately large median projection, possessing 2 pairs of ordinary sub-terminal spines and 2 pairs of dorsolateral spines, anterior pair of latter ones situated just anterior to mid-length. Antennal scale 0.8 times as long as carapace, 3.3 times as long as wide. Epistome without anteromedian lobe (bi-lobed). First pereopod extending beyond antennal scale by length of chela. Second pereopods (Fig. 19 a, b) sub-equal in length, shorter than entire body, extending beyond antennal scale by one-third of carpus and onwards; merus slightly longer than carpus, latter as long as palm; fingers 0.75 times as long as palm, without tubercles or teeth on cutting edges. Third pereopod (Fig. 19 c, d) with propodus 2.8 times longer than dactylus. Appendix masculina (Fig. 19 e) with stiff setae on anterior margin and several setae aligned on mesial surface. Exopod of uropod (Fig. 19 f) sub-equal in length to endopod, movable spine on diaeresis longer than lateral projection. Remarks. This specimen was regarded as adult because its appendix masuculina (Fig. 19 e) is well developed and superficially resembles M. tratense. However, it differs from the latter species in having a comparatively shorter rostrum, with fewer teeth on both the dorsal and ventral margins, and the second pereopod was proportionately shorter than that of the latter species (cf. Cai et al. 2004; Figs. 3–5 a). The present specimen also somewhat resembles the Chinese M. inflatum Liang & Yan, 1985, in particular with regard to those reported from the Yunnan Province, south-eastern China (Cai & Dai 1999; Fig. 8). However, the palm of the second pereopod is distinctly longer than the fingers in the Laotian specimen while it is shorter or sub-equal length in M. inflatum. More materials are needed before its identity can be ascertained.

Macrobrachium sintangense (De Man, 1898) (Figs. 11, 12) Palaemon (Eupalaemon) sintangensis De Man, 1898: 138, pl. 6. Macrobrachium sintangense: Holthuis 1950: 151; Ng 1994: 77, fig. 6; Cai et al. 2004: 592, fig. 2; Nguyen 2006: 235 ���253, figs. 2 c, d, 3 k, l. Material examined. Luang Prabang Province: Mekong River, Pakxeng Village, 1 male (CL 17.5 mm) 2 females (CL 13.0 mm, 13.3 mm), March 2001, coll. O. Lasasimma (LARReC C012, as Macrobrachium sp. 3). Champasak Province: Det Island, 3 males (CL 7.1���8.7 mm), 1 female (CL 9.8 mm), 11 July, 2009, set net, coll. S. Ito & Y. Niimura; Khone Island, 1 male (CL 10.4 mm), 10 July 2009, set net, coll. S. Ito & Y. Niimura; Det Island, 6 males (CL 9.1 ���18.0 mm), 14 females (CL 13.5���16.2 mm), 5 ovig. females (CL 12.5���16.5 mm), set net, 21 July 2009, coll. Y. Niimura; Det Island, 1 male (CL 8.0 mm), 2 females (CL 8.2 mm, 8.4 mm), 1 ovig. female (CL 12.0 mm), set net, 23 July 2009, coll. Y. Niimura. Diagnosis. Rostrum (Figs. 11 a, b, 12 a, b) fully reaching or extending well beyond anterior end of antennal scale, dorsal margin weakly or distinctly curving dorsad, armed dorsally with 10���12 teeth including 2 or 3 placed posterior to orbital margin, ventrally with 4 or 5 teeth; antennal spine placed just behind lateral margin, apex extending beyond end of antennal lobe; hepatic spine as large as antennal spine, placed posteriorly, just below level of antennal spine. Sixth abdominal somite 1.25���1.45 times as long as fifth one; pre-anal carina poorly developed but traceable as obtuse swelling. Telson 1.65���1.85 times as long as sixth abdominal somite, ending in moderately sharp median projection, with 2 pairs of ordinary sub-terminal spines and 2 pairs of dorsolateral spines, anterior pair of latter ones situated at mid-length or just beneath it. Antennal scale 0.7���0.75 times as long as carapace, about 3 times as long as wide. Second male pereopods sub-equal in length, slender and slightly longer than total body length, with mero-carpal articulation barely reaching anterior end of antennal scale, with minute spinules on almost its entire length; merus shorter than carpus; carpus slightly longer than palm; fingers (Figs. 11 c, 12 c) about two-thirds length of palm, its basal half covered with short velvety setae, no grooves present; cutting edge of movable finger with 2 teeth and that of fixed finger with single tooth near basal part. Third pereopod (Figs. 11 d, e, 12 d) with propodus about 3.0��� 3.9 times as long as dactylus. Appendix masculina (Figs. 11 f, 12 f) slightly less than twice length of appendix interna, with moderately long setae on anterolateral margin and several stiff setae scattered on mesial surface. Exopod of uropod (Figs. 11 g, 12g) slightly longer than endopod, movable spine on diaeresis as long as or slightly longer than lateral projection. Egg. Eyed-eggs about 1.0��� 1.1 x 1.5���1.8 mm Remarks. In our specimens, males larger than 16 mm in carapace length had velvety setae on the fingers of the second pereopods, although the second legs showed some variations in their morphological structure depending on specimens. Females of comparable body size had proportionately shorter second pereopods than males and did not bear velvety setae except for one female of 14.5 mm in carapace length with scattered fine setae. Moreover, the second pereopods of young males and females were variable in ornamentation, from nearly smooth to spinous. Thus, the ornamentation (velvety setae and teeth/protuberances) of the second pereopod seemed to develop only in late stages of life. Hence, sub-adult specimens (cf. Fig. 12) showed a closer resemblance to M. tratense established by Cai et al. (2004) from Thailand. Ng (1994) recorded this species from the Sabah, eastern Malaysia, which was followed by Cai et al. (2004). The rostrum of Ng���s (1994) specimens had more widely set teeth on the ventral margin, and this may suggest that they are not con-specific. Cai et al. (2004) noted that the taxonomy of M. sintangense (type locality central Borneo) may not be so straightforward as a synonym, Palaemon elegans De Man, 1892 (type locality Java), is probably a valid species. Macrobrachium sintangense resembles M. saigonensis Nguyen, 2006 recorded from southern Vietnam. According to Nguyen (2006), M. saigonensis has much larger body size and second pereopod than others in this species and bears smaller eggs (Nguyen, 2006). Furthermore, M. sintangense occurs entirely in fresh waters, while M. saigonensis inhabits slightly haline waters (0���12 in salinity). Distribution. Known with reasonable certainty from Borneo, Peninsular Malaysia, and Thailand, through Yunnan, and now in Laos (Liu et al. 1990; Cai & Dai 1999; Cai et al. 2004; present study). Macrobrachium sintangense is exploited for human consumption in southern Laos., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 20-23, DOI: 10.5281/zenodo.204065, {"references":["De Man, J. G. (1898) Macrura. Zoological results of the Dutch Scientific Expedition to central Borneo. The crustaceans, Part 1. Notes from the Leiden Museum, 20, 137 - 161, pls. 6 - 8.","Holthuis, L. B. (1950) The Palaemonidae collected by the Siboga and Snellius Expeditions, with remarks on other species. I. Subfamily Palaemoninae. Siboga-Expeditie, 39 a 9, 1 - 268.","Ng, P. K. L. (1994) On a collection of freshwater decapod crustaceans from the Kinabatangan River, Sabah, Malaysia, with descriptions of three new species. Sabah Museum Journal, 1, 73 - 92.","Nguyen, V. - X. (2006) A new species of freshwater prawn of the genus Macrobrachium, similar to Macrobrachium sintangense (De Man, 1898) (Decapoda, Caridea, Palaemonidae) from south Vietnam, and description of its zoea. Crustaceana, 79, 235 - 254.","De Man, J. G. (1892) Decapoden des Indischen Archipels. In: Weber, M. (Ed.), Zoologische Ergebnisse einer Reise in Niederlandisch Ost-Indien, 2, 265 - 527, pls. 15 - 29.","Liu, J. Y., Liang, X. & Yan, S. (1990) A study of the Palaemonidae (Crustacea Decapoda) from China I. Macrobrachium, Lean- der, and Leandrites. Transactions of the Chinese Crustacean Society, 2, 102 - 133. (in Chinese)"]}

Macrobrachium mieni Dang, 1975 (Fig. 8) Macribrachium mieni Dang, 1975: 68, fig. 2: Dang 1980: 389, fig. 223; Cai et al. 2004: 613, fig. 11. Material examined. Luang Prabang Province: Ou River, Ngoi District, 2 males (CL 11.3 mm, 15.0 mm), Sept 2000, coll. O, Lasasimma; Xuang River, Na Pho Village, St. 3, 2 males (CL 10.5 mm, 12.5 mm), 20 Oct 2007, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 2, 1 male (CL 17.0 mm), 1 female (CL 8.8 mm), 28 Dec 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 2, 1 male (CL 15.2 mm), 27 Apr 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 3, 1 male (11.5 mm), 25 May 2008, hand net, coll. S. Ito et al. Vientiane Province: Kasi District, 1 female (CL 12.0 mm), 22 May 2008, hand net, coll. S. Ito et al.; Kasi District, 1 female (CL 16.0 mm), 30 Jan 2009, hand net coll. S. Ito et al.; Kasi District, 2 males (CL 19.9 mm, 20.0 mm), 1 Nov 2009, hand net, coll. S. Ito et al. Vientiane Capital: Nong Niew Market, 2 ovig. females (CL 10.8 mm, 11.5 mm), 31 Aug 2007, coll. H. Ikenoue. Champasak Province: Det Island, 1 male (CL 9.5 mm), 11 July 2009, set net, coll. S. Ito & Y. Niimura; Det Island, 1 male (CL 9.8 mm), 1 female (CL 6.2 mm), 23 July 2009, set net, coll. Y. N i i m u r a. Diagnosis. Rostrum (Fig. 8 a) straight or slightly directed ventrad, 0.35���0.4 times as long as carapace and usually falling slightly short of anterior end of antennular peduncle, dorsal margin armed with 9���15 teeth including 2��� 5 situated posterior to orbital margin, ventral margin with 2���4 teeth; antennal lobe moderately developed, antennal spine placed just behind lateral margin, apex extending slightly beyond antennal lobe; hepatic spine smaller than antennal spine, situated posteriorly, distinctly below level of antennal spine. Abdomen with sixth somite 1.3���1.4 times as long as fifth, pre-anal carina represented by obtuse ridge; anterior 3 abdominal sternites each with moderately developed median tooth, third one smaller than precedent ones. Telson 1.5���1.6 times as long as sixth abdominal somite, posterior margin sub-triangular, possessing 2 pairs of ordinary sub-terminal spines and 2 pairs of dorsolateral spines, anterior pair of latter spines placed slightly posterior to midlength of telson. Antennal scale 0.4���0.6 times as long as carapace, 2.6���3.2 times as long as wide. Epistome (Fig. 8 b) normally without anteromedian projection (bi-lobed). First pereopods extending beyond antennal scale by carpus and onwards, fingers about 0.75 times as long as palm. Second pereopods (Fig. 8 c, d) equal or slightly unequal in length, extending beyond antennal scale by almost whole length of carpus and onwards, sub-equal in length to total body length; merus slightly longer than carpus, with numerous spinules on entire surface; carpus as long as or slightly shorter than palm, covered by numerous spinules on entire surface; palm nearly smooth except for several short setae scattered on surface; fingers as long as or slightly shorter than palm, not gaping when closed, armed with less than 10 small teeth at most on basal twothirds. Propodus of third pereopod (Fig. 8 e) 2.9���3.5 times as long as dactylus, with 5���8 well spaced spines on posterior margin. Appendix masculina (Fig. 8 f) 0.5���0.7 times as long as appendix interna, with numerous stiff setae on anterolateral margin as well as mesial surface. Uropodal exopod (Fig. 8 g) as long as or slightly longer than endopod, movable spine on diaeresis noticeably shorter than lateral projection. Remarks. Macrobrachium mieni resembles M. yui Holthuis, 1950, in general appearance, but it could be distinguished from the latter species by having a movable spine on the diaeresis of the uropodal exopod (Fig. 8 g) as opposed to no spine in M. yui in specimens larger than 15 mm in carapace length (Fig. 17 d) (see also ���Remarks��� under the latter species). In fully grown males, the second pereopod of M. mieni (Fig. 8 a) is comparatively smaller than that of M. yui (Fig. 16). In fresh specimens of M. mieni, a yellowish stripe running along the dorsal margin of the entire length of the abdominal somites was observed. Distribution. This species has been reported with reasonable certainty from northern Vietnam, Thailand, and Laos (Dang 1980; Cai et al. 2004; present study)., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 14-16, DOI: 10.5281/zenodo.204065, {"references":["Dang, N. T. (1975) The identity of North Vietnamese freshwater shrimps and crabs. Journal of Biology-Geology, 13 (3), 65 - 78. (in Vietnamese)","Dang, N. T. (1980) The identity of freshwater invertebrates of North Vietnam. Decapoda (Hanoi, Vietname), pp. 380 - 418. (in Vietnamese)","Holthuis, L. B. (1950) The Palaemonidae collected by the Siboga and Snellius Expeditions, with remarks on other species. I. Subfamily Palaemoninae. Siboga-Expeditie, 39 a 9, 1 - 268."]}

Rhopalophthalmus orientalis O. Tattersall, 1957 (Figs. 14���17) Rhopalophthlmus orientalis O. Tattersall, 1957: 91, fig. 2 a���f. ��� Ii 1964: 173, figs. 44, 45. ��� Tattersall 1965: 79, fig. 1. ��� Wang & Liu 1997: 205, fig. 4. ��� Liu & Wang 2000: 116, fig. 28. Rhopalophthalmus egregious ��� Nakazawa 1910: 255, pl. 8, figs. 12, 22. ��� Tattersall, 1921: 408. Material examined. Japan. Todoro, Miyazaki Prefecture: 18 males (all damaged), 13 females (BL ca. 7.5���11.5 mm), 1 ovig. female (BL ca. 11 mm); 31 Oct 1937, coll. N. Ii (NSMT Cr 21232). ��� Susaki, Kochi Prefecture: 3 females (all damaged), 1 juv. (BL 5.0 mm), 20 abdomens of males and females; 20 Nov 1935, coll. N. Ii (No. 241) (NSMT Cr 21233). ��� Susaki-Inlet, Kochi Prefecture: 23 males (BL ca. 8.5���12.5 mm), 28 females (BL ca. 7.7���12 mm), 7 ovig. females (BL ca. 10.5���11 mm); 24 Aug 1933, coll. N. Ii (No. 243) (NSMT Cr 21234). ��� Coast of Natsushima, Tsuruga, Fukui Prefecture: 43 males (BL ca. 7���12 mm), 33 females (BL ca. 7���11 mm), 1 ovig. female (BL 11.8 mm), 1 juv.; 2 Nov 1938, coll. N. Ii (No. 261) (NSMT Cr 21235). ��� Ariake Bay, Nagasaki Prefecture: 3 males (BL ca. 8���12.2 mm), 3 females (BL ca. 9.5���11.5 mm) (slightly damaged due to dried); sledge, 6 m depth, mud, 25 June 1975, coll. T. Takita (NSMT Cr 21236). ��� Tateyama Bay, entrance of Tokyo Bay, Chiba Prefecture: 1 male (BL ca. 7.5 mm); 19 June 1975, other details unknown (NSMT Cr 21237). ��� Off Kawanoe, Hiuchi-nada, Seto Inland Sea: 1 ovig. female (BL ca. 11 mm); 16 Nov 1994, from stomach of five spot flounder Pseudorhombus pentophthalmus G��nther, 1862, coll. R. Shibata (NSMT Cr 21238). Thailand. Sapum Bay, Phuket Is.: 2 males (BL ca. 6.0, ca. 7.0 mm), 5 females (BL ca. 7.5���9.5 mm), 1 abdomen; 19 Feb 1980, coll. Marine Fisheries Laboratory, Department of Fisheries, Thailand (NSMT Cr 21342). Malaysia. Matang mangrove estuary: 1 male (BL 9.7 mm); St. 2, 4˚ 50.6 ' N, 100 ˚ 35.3 ' E, sledge, 4.5 m depth, 8 Apr 2005, coll. Y. Hanamura (NSMT Cr 21239). ��� 15 males (BL 6.5���9.5 mm), 16 females (BL ca. 5.3���12 mm), 11 ovig. females (BL 8.7���11.3 mm); St. 2, 5˚ 39.2 ' N, 100 ˚ 23.9 ' E, sledge, 4.5 m depth, 8 Apr 2005, coll. Y. Hanamura (NSMT Cr 21240). ��� 44 males (BL 5.0��� 9.5 mm), 50 females (BL 5.1 ���10.0 mm), 11 ovig. females (BL 8.7��� 9.5 mm), 45 juvs. (BL 2.6���5.1 mm); offshore of St. 4 (4 ˚ 51.4 ' N, 100 ˚ 32.9 ' E), sledge, 2.4 m depth, 14 June 2006, coll. Y. Hanamura (NSMT Cr 21241). ���Merbok mangrove: 32 males (BL 5.9���9.2 mm), 17 females (BL 5.7���9.7 mm), 7 ovig. females (BL 8.3���9.8 mm), 2 juvs. (BL 2.5, 3.2 mm); St. B, 5 ˚ 39.2 ' N, 100 ˚ 23.9 ' E, sledge, 2 m depth, 10 Aug 2005, coll. Y. Hanamura (NSMT Cr 21242). ��� 5 males (BL 5.5���9.7 mm), 2 females (BL 6.8, 8.8 mm), 1 ovig. female (BL 9.3 mm), 2 juvs. (BL 4.2, 4.5 mm); St. C, 5 ˚ 38.5 ' N, 100 ˚ 24.9 ' E, sledge, 5.4 m depth, 14 Dec 2004, coll. Y. Hanamura (FRI 008). Indonesia. Tegal, central Java: 1 juv. (BL 3.0 mm); 3 June 1994, coll. Mulyadi (identification tentative) (NSMT Cr 21243). Description. Body moderately robust (Fig. 14 a). Anterior dorsal part of carapace between postorbital spines weakly produced, forming wide, sub-triangular rostrum with rounded apex (Figs. 14 a���d, 17 a, b); cervical sulcus marked dorsally and laterally around anterior onethird; anterior medial nodule small but well defined, situated just posterior to cervical sulcus, and slightly larger posterior nodule situated close to posterior carapace margin; postorbital spine small and carina supporting spine not developed or feebly ridged; cheeks slightly sinuous; antero-lateral spine moderately long, reaching as far as end of rostral plate. Eyes (Figs. 14 a���d, 17 a, b) sub-pyriform, fully reaching mid-length of second segment of antennular peduncle, cornea well pigmented, broader than eye stalk. Antennules sexually dimorphic (Figs. 14 g, h); male peduncle with basal segment as long as combined length of distal 2 segments, with several long inwardly curving setae along lateral margin (slightly deformed in figure due to artifact); second segment shortest, slightly shorter than wide; third segment slightly longer than wide, with several short hooked setae on mesial margin and several long setae around disto-mesial part, lateral flagellum basally swollen, forming male lobe, hirsutid densely on mesial margin with long hair. Female antennular peduncle more slender than that in males, first segment of peduncle longer than combined length of anterior 2 segments, with several long inwardly curving setae (slightly deformed in figure due to artifact); second segment shortest, slightly shorter than wide; third segment slightly longer than wide, with several long ordinary setae around disto-mesial part. Antennal scale (Figs. 15 a, 17 e) barely reaching end of antennular peduncle, about 5 times as long as wide, disto-lateral spine slightly overreaching end of blade, distal suture present; sympod with 2 stout spines of sub-equal length and commonly with 2, rarely 1, small spines at base of stout spines. Labrum with anterior margin nearly truncated, without median spine. Mouthparts as illustrated in Ii (1964: figs. 44 j���l). Thoracic appendages: endopods of thoracic limbs moderately long, reaching anterior end of carapace (Figs. 15 b���g, 17 f, g); third thoracic endopod slightly stouter than fourth, its carpo-propodus commonly consisting of 4 or 5 articles; fourth to sixth thoracic endopods similar in shape, carpo-propodi with 4���6 articles; seventh thoracic endopod with carpo-propodus composed of 4���6 articles, longest setae rather smooth, without stout setules. Rudimentary endopod of eighth thoracic limb in males (Figs. 15 h, 17 h) 3 -segmented, usually curving anteriorly, reaching around distal one-third when extended; second segment shortest, with several long setae; distal segment elongated, rod-shaped. Rudimentary endopod of eighth thoracic limb in females (Figs. 15 i, 17 i) un-articulated, slightly variable in length, fully extending to falling slightly short of distal end of basal plate of exopod. Abdominal somites (Fig. 14 a) rounded dorsally, without any ornamentation; first to fifth somites sub-equal in length, sixth somite 1.1���1.4 times as long as fifth one; male first somite rounded ventrally to form pleuron with shallow excavation near anterior part. Pleopods in males biramous (Figs. 15 j���l); first pleopod with endopod un-articulated, with several short marginal setae, first pleopod with exopod multi-articulated; second pleopodal exopod greatly elongated, consisting of about 13 articles, terminal article armed with 2 apical setae and one proportionately long sub-apical seta, several basal articles each with long seta, and unarmed in several articles between these armed articles; third to fifth pleopods similar in shape, with multi-articulated endopods and exopods of sub-equal length. Pleopods in females (Figs. 16 a���c) un-articulated, length increasing on posterior somites. Uropod (Figs. 14 f, 17 d) with 2 -segmented exopod and endopod; distal segment of exopod about half-length of basal segment; endopod with distal segment about two-fifths as long as basal segment, bearing stout seta on ventral margin near statocyst. Telson (Figs. 14 e, 17 c) 1.1���1.4 times as long as sixth abdominal somite, extending (without spinose apical setae) to articulation of uropodal endopod, and spinose apical setae extending beyond articulation of uropodal exopod by about half of setal length, length of telson about 2.5 times basal width and again about 4 times, or slightly fewer times, as long as wide at sub-basal constricted part, narrowed abruptly at base, forming discernible waist and slightly wider near mid-length, then gradually narrowing toward posterior end; rounded posterior margin with 2 pairs of stout spinose setae, mesial pair extending as far as or slightly beyond lateral pair, setules becoming broadened distally; lateral margin of telson armed with 11���16 (commonly with 14 or 15 in Japanese and 12 or 13 in Malaysian specimens) smooth setae, increasing its length posteriorly. Body length. Largest recorded male: BL 12.5 mm, largest female: BL ca. 12 mm. Colour. In Malaysian specimens, entire body almost semi-transparent when alive, while telson with basal red chromatophore but no chromatophore at mid-length, unlike sympatric R. egregius and R. hastatus, both with two red chromatophores. Egg size. Female of BL 9.0 mm carried 8 embryos, eggs (stage I embryos) spherical, measuring 0.60���0.80 mm along longest axis (N= 7). Remarks. No substantial differences could be found in morphology between our materials and published data for R. orientalis (Ii 1964; Tattersall 1957, 1965; Liu & Wang 2000). Among the specimens so far examined, however, the Malaysian specimens showed a tendency to have smaller body size than the Japanese ones, and the Malaysian population also possessed slightly fewer numbers of lateral setae on the telson (commonly 12 or 13 setae vs. 14 or 15 in Japanese one) and fewer number of articles in the carpo-propodi of the fourth to seventh thoracic endopods, each commonly composed of four or five articles compared to five or six in Japanese specimens. Furthermore, the rudimentary endopods of the eighth thoracic limbs are proportionately longer in Malaysian specimens than in Japanese ones in both sexes. These differences, however, appeared to be bridged by the Chinese population (cf. Liu & Wang 2000), although the identity of R. orientalis may be a subject of future taxonomic studies over its geographical scale. Rhoplaophthalmus orientalis can be distinguished from its congeners, which have a combination of following features: 1) the antennal sympod with two stout spines and one or two much smaller lateral spines, 2) the antennal scale barely reaching the end of the antennular peduncle, and 3) the telson possessing a marked ���waist��� near base. Rhopalophthalmus anishi Panampunnail & Biju, 2006, R. mumbayensis Panampunnail & Biju, 2006, and R. tropicalis Wooldridge & Mees, 2003 have the telson with the lateral pair of the spinose apical setae longer than the mesial pair as opposed to shorter setae in R. orientalis. Rhopalophthalmus kempi O. Tattersall, 1957 has the third to seventh thoracic endopods with three-segmented carpo-propodus against the four or five-segmented one, and the rudimentary endopods of the eighth thoracopods are proportionately longer in both sexes than those in R. orientalis, extending well beyond the basal plate of the exopod as opposed to barely reaching or slightly shorter in R. orientalis. Rhopalophthalmus murudana Panampunnail & Biju, 2006 has, as reported so far, a proportionately short telson with the distal margin excluding the spinose apical setae falling far short of the articulation of the uropodal endopod while fully reaching that articulation in M. orientalis. The eyes of R. murudana are also comparatively short with the cornea barely reaching the end of the first peduncular segment of the antennules as opposed to extending well beyond it in R. orientalis. Rhopalophthalmus tattersallae Pillai, 1961 has a prominent sub-triangular rostrum, and the rudimentary endopod of the eighth thoracic limb in the female is two-segmented and noticeably shorter when compared with an unarticulated endopod in R. orientalis. On the other hand, Pillai (1964) suggested a similarity between R. macropsis and R. orientalis, but R. macropsis has an elongated endopod in the male eighth thoracopods as well as a proportionately more slender telson with the lateral pair of the spinose apical setae longer than the inner pair. Distribution. This species has been recorded with certainty from shallow coastal waters of Japan (Nakazawa 1910; Tattersall 1957; Ii 1964), East China Sea (Liu & Wang 2000), and Malacca Strait (Tattersall 1965; present study). Habitat. In the estuarine systems of Matang and Merbok mangroves, Peninsular Malaysia, R. orientalis were usually captured in the mouth area to middle reaches (Hanamura et al. 2007; as Rhopalophthalmus sp. 2)., Published as part of Hanamura, Yukio, Murano, Masaaki & Man, Alias, 2011, Review of eastern Asian species of the mysid genus Rhopalophthalmus Illig, 1906 (Crustacea, Mysida) with descriptions of three new species, pp. 1-37 in Zootaxa 2788 on pages 23-29, DOI: 10.5281/zenodo.207815, {"references":["Tattersall, O. S. (1957) Report on a small collection of Mysidacea from the Sierra Leone Estuary together with a survey of the genus Rhopalophthalmus Illig and a description of a new species of Tenagomysis from Lagos, Nigeria. Proceedings of the Zoological Society of London, 129, 81 - 128.","Ii, N. (1964) Mysidae. Fauna Japonica. Biogeographical Society of Japan, Tokyo. 610 pp.","Tattersall, O. S. (1965) Report on a small collection of Mysidacea from the northern region of the Malacca Strait. Journal of Zoology, London, 147, 75 - 98.","Wang, S. & Liu, J. Y. (1997) Mysidacea fauna of the East China Sea. Studia Marina Sinica, 38, 191 - 222. (in Chinese)","Liu, R. & Wang, S. (2000) Order Mysidacea (Arthropoda Crustacea Malacostraca). Fauna Sinica. Science Press, Beijing, 326 pp. (in Chinese)","Nakazawa, K. (1910) Notes on Japanese Schizopoda. Annotationes Zoologicae Japonenses, 7, 246 - 261, pl. 8.","Tattersall, W. M. (1921) Mysidacea, Tanaidacea and Isopoda. Zoological results of a tour in the Far East. Memoirs of the Asiatic Society of Bengal, 6, 403 - 443, pls. 15 - 17.","Panampunnayil, S. U. & Biju, A. (2006) Four new species of the genus Rhopalophthalmus (Mysidacea: Crustacea) from the northwest coast of India. Journal of Natural History, 40, 1389 - 1406.","Wooldridge, T. H. & Mees, J. (2003) Additions to the mysid fauna (Crustacea: Mysidacea) from coastal waters of Mozambique, with descriptions of two new species. Hydrobiologia, 505, 31 - 39.","Pillai, N. K. (1961) Additions to the Mysidacea of Kerala. Bulletin of the Central Research Institute, University of Kerala, Trivandrum, 8, 15 - 35, pls. 1 - 6.","Pillai, N. K. (1964) Report on the Mysidacea in the collections of the Central Marine Fisheries Research Institute, Mandapam Camp, south India-Part I. Journal of the Marine Biological Association of India, 6, 1 - 41.","Hanamura, Y., Siow, R. & Chee, P. E. (2007) Abundance and spatio-temporal distribution of hyperbenthic crustaceans in the Merbok and Matang mangrove estuaries, Malaysia. JIRCAS Working Report, 56, 35 - 41."]}

Macrobrachium rosenbergii (De Man, 1879) Palaemon d���Acqueti Sunier, 1925: 117. Macrobrachium rosenbergii: Jayachandran 2001: 158, figs. 11, 12: Hanamura et al. 2008: 1144, figs. 1, 2. Macrobrachium rosenbergii dacqueti: Holthuis 1995: 148; Cai & Ng 2002: 78; Cai et al. 2004: 582. Macrobrachium dacqueti: Wowor & Ng 2007: 326, figs. 4, 5b���c, 6, 7b, 9, 10. Macrobrachium rosenbergii: Ng & Wowor 2011: 66 ���67. Material examined. Champasak Province. Morning market at Pakse city, 1 femele (CL 66.5 mm), 1 ovig. female (CL 58.5 mm), 12 July 2009, coll. S. Ito et al. Remarks. Macrobrachium rosenbergii is one of the best-known freshwater prawns in the world. The identity of two distinct geographical populations (eastern and western forms) have long been a subject of taxonomic and nomenclatural controversy, although the results of morphological and DNA analyses have suggested that they could be different species (Wowor & Ng 2007, 2008). The present specimens well fit the morphological characteristics of the western form, currently as M. rosenbergii (see ICZN 2010; Ng & Wowor 2011), by having a marked rostral crest and smooth inter spine surfaces on the second pereopods as well as the absence of the posterior submedian plate on the fourth thoracic sternite (Wowor & Ng 2007). Distribution. Macrobrachium rosenbergii is originally distributed in southern Asia (Jayachandran 2001) and the western part of south-eastern Asia, demarcated by the Huxley���s line (de Bruyn et al. 2004; Wowor & Ng 2007; Ng & Wowor 2011), although it has occasionally been reported outside of its natural habitat as a consequence of human introduction. The presence of M. rosenbergii in southern Laos is believed to be derived from aquaculture ponds of this species in north-eastern Thailand. Recently, colonisation of this species was found in Madagascar (Hanamura et al. 2008)., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on page 20, DOI: 10.5281/zenodo.204065, {"references":["Sunier, A. L. J. (1925) Twee mededeelingen over Palaemoniden. Tijdschrift der Nederlandsche Dierkundige Vereeniging, (2) 19, cxv - cxvii.","Jayachandran, K. V. (2001) Palaemonid prawns: biodiversity, taxonomy, biology and management. Science Publishers, Inc., Enfield, USA, 624 pp.","Hanamura, Y., Koizumi, N., Morioka, S., Andriantosa, M. & Rafalimana, T. (2008) Occurrence of the non-indigenous fresh water prawn, Macrobrachium rosenbergii (De Man, 1879) (Decapoda, Caridea, Palaemonidae) in Madagascar. Crustaceana, 81, 1143 - 1149.","Holthuis, L. B. (1995) Notes on Indo-West Pacific Crustacea Decapoda III to IX. Zoologische Mededelingen, 69, 139 - 151.","Cai, Y. & Ng, P. K. L. (2002) The freshwater palaemonid prawns (Crustacea: Decapoda: Caridea) of Myanmar. Hydrobiologia, 487, 59 - 83.","Ng, P. K. L. & Wowor, D. (2011) On the nomenclature of the palaemonid names Palaemon spinipes Desmarest, 1817, Palaemon spinipes Schenkel, 1902, and Macrobrachium wallacei Wowor & Ng, 2008 (Crustacea: Decapoda: Caridea). Zootaxa, 2904, 66 - 68.","De Bruyn, M., Wilson, J. A. & Mather, P. B. (2004) Huxley's line demarcates extensive genetic divergence between eastern and western forms of the giant freshwater prawn, Macrobrachium rosenbergii. Molecular Phylogenetics and Evolution, 30, 251 - 257."]}

Macrobrachium dienbienphuense Dang & Nguyen, 1972 (Figs. 3, 4) Macrobrachium dienbienphuense Dang & Nguyen, 1972: 4, fig. 3; Dang 1980: 384, fig. 220; Liu et al. 1990: 121, fig. 19; Cai & Dai 1999: 223, fig. 9; Cai et al. 2004: 634, figs. 14 h, 1, 20; Li et al. 2007: 84 (part). Macrobrachium longidigitum Dai, 1984: 248, figs. 18���22. Material examined. Luang Prabang Province: Mekong River, Pakxeng Village, 2 males (CL 12.4 mm, 14.6 mm), 1 ovig. female (CL 13.0 mm), Feb 2001, coll. O. Lasasimma; Xuang River, Na Pho Village, St. 3, 1 ovig. female (CL 10.0 mm), 27 Mar 2007, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 2, 1 male (CL 10.5 mm), 27 Apr 2008, hand net, coll. S. Ito et al.; Morning market, Luang Prabang city, 24 males (CL 8.6���17.7 mm), 5 females (CL 7.2 ���10.0 mm), 26 Feb 2009, coll. S. Ito et al. Diagnosis. Rostrum (Figs. 3, 4 a) slightly longer than half length of carapace, barely reaching or slightly overreaching end of antennular peduncle, dorsal margin usually convex, armed with 11���13 teeth including 3���5 situated posterior to orbital margin, ventral margin with 2 or 3 teeth; antennal spine sharp, arising just behind lateral margin, apex extending well beyond antennal lobe; hepatic spine slightly smaller than antennal spine, situated posteriorly, below level of antennal spine. Sixth abdominal somite 1.4���1.5 times as long as fifth, pre-anal carina sharp, triangular in shape. Telson 1.4���1.7 times as long as sixth abdominal somite, posterior margin triangular, with moderately developed median projection and 2 pairs of ordinary sub-terminal spines in addition to 2 pairs of dorsolateral spines, anterior pair of latter ones situated near mid-length. Epistome (Fig. 4 b) with anteromedian projection (tri-lobed), but occasionally anteromedian lobe indistinct. Antennal scale 0.6���0.7 times as long as carapace, 2.7 ���3.0 times as long as wide. Third maxilliped reaching midlength of antennal scale, distal segment slightly shorter than penultimate one. First pereopod extending beyond antennal scale by half length of carpus and onwards, fingers 0.7���0.8 times as long as palm. Second pereopods (Figs. 3, 4 a, c) distinctly unequal in length but similar in shape, palm and fingers (also occasionally carpus and ventral part of merus) covered with long velvety setae: major leg as long as to noticeably longer than total body length in fully grown male, extending beyond antennal scale by half length of merus and onwards; merus not inflated, 3.75���4.25 times as long as high, sub-equal in length to palm, covered with numerous spinules over its length; carpus elongated and sub-cylindrical, 2.4���2.9 times as long as high, with minute spinules on lateral surface; palm comparatively slender, sub-equal or shorter than fingers, 3.1���3.8 times as long as wide; fingers markedly gaped when closed, with 18���22 tuberculate teeth on cutting edges; minor leg overreaching antennal scale by chela, fingers sub-equal in length to palm. Third pereopod (Fig. 4 d, e) with propodus 2.3 ���3.0 times as long as dactylus, with 5 or 6 spines along posterior margin. Appendix masculina (Fig. 4 f) about twice length of appendix interna, with numerous stiff setae on anterolateral margin as well as mesial surface. Exopod of uropod sub-equal or slightly longer than endopod, movable spine on diaeresis (Fig. 4 g) as long as or slightly shorter than lateral projection. Egg. Eggs oblong, moderately large in size, non-eyed eggs measuring 0.90 ���1.0 x 1.35���1.50 mm Remarks. Li et al. (2007) considered, as mentioned above, that M. dienbienphuense is a senior synonym of M. amplimanus, M. eriocheirum, and M. pilosum. In Laotian specimens examined so far, the merus of the second pereopod of M. dienbienphuense is nearly cylindrical (Figs. 3, 4 a) rather than inflated in those attributed to M. amplimanus or M. eriocheirum (Figs. 2 c, 6 a, b). Moreover, the carpus of the same leg of M. dienbienphuense is elongated, forming a sub-cylindrical structure, about twice and a half or more as long as high rather than a cupshaped carpus shorter than two times of its maximum high (Table 2). The fingers of the second pereopod in M. dienbienphuense also have more numerous teeth than those in its two congeners (18���22 vs. 12���17 teeth). Although females and immature males were often difficult to speciate, the adult male characters are diagnostic. from the Luang Prabang Province, northern Laos. Characters M. amplimanus M. dienbienphusense M. eriocheirum Major second pereopod To clarify morphological observations, a 472 -bp region of the 16 S ribosomal RNA gene in mitochondrial DNA was sequenced, and the result of analyses yielded the three genetically different clades shown in Fig. 5. Although specimens within Clade B are genetically divergent (0.5 ���1.0%), the nucleotide divergences between Clade B and Clade C are much higher (3.3���3.5 %) than this level. Hence, the DNA gene analysis, coupled with the morphological features, confirmed the recognition of three genetically distinct groups: i.e., Clade A attributed to M. amplimanus; Clade B, M. eriocheirum; and Clade C, M. dienbienphuense. Cai & Dai (2004) noted that the second pereopod of M. pilosum are densely covered with velvety setae on the fingers through the merus. Specimens collected from the Luang Prabang Province, northern Laos, often have sparse velvety setae on an anterior part of the merus of the second pereopod (see Cai & Dai 2004; Figs. 10, 11), but we could not find any individuals bearing dense setae on the entire length of the merus, as it has been shown in the typical M. pilosum. Moreover, the second major chela of our specimens had proportionately longer fingers (longer than palm) and also a relatively long rostrum reaching the anterior end of the antennular peduncle. The identity of M. pilosum is needed to be re-examined in future studies. Distribution. Northern Vietnam, Yunnan Province in south-western China, Thailand, and Laos (Dang 1980; Cai & Dai 1999; Cai et al. 2004; present study)., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 6-9, DOI: 10.5281/zenodo.204065, {"references":["Dang, N. T. & Nguyen, H. Y. (1972) Information on freshwater prawn genus Macrobrachium Bate (Palaemonidae) from the mountainous regions of North Vietnam. Journal of Biology-Geology, 10 (1 - 4), 1 - 6. (in Vietnamese)","Dang, N. T. (1980) The identity of freshwater invertebrates of North Vietnam. Decapoda (Hanoi, Vietname), pp. 380 - 418. (in Vietnamese)","Liu, J. Y., Liang, X. & Yan, S. (1990) A study of the Palaemonidae (Crustacea Decapoda) from China I. Macrobrachium, Lean- der, and Leandrites. Transactions of the Chinese Crustacean Society, 2, 102 - 133. (in Chinese)","Li, X., Liu, R., Liang, X. & Chen, G. (2007) Crustacea, Decapoda, Palaemonidea. Fauna Sinica, Invertebrate, vol. 44. Science Press, Beijing, 381 pp. (in Chinese)","Dai, A. Y. (1984) A preliminary study on the freshwater prawn genus Macrobrachium of China (Decapoda, Caridea). Acta Zootaxonomica Sinica, 9, 244 - 252. (in Chinese)"]}

Macrobrachium thai Cai, Naiyanetr & Ng, 2004 (Fig. 15) Macrobrachium thai Cai, Naiyanetr & Ng, 2004: 605, figs. 8, 9. Material examined. Khammouane Province: Theun River, 6 males (CL 4.2���9.4 mm), 7 females (CL 4.0��� 12.2 mm), 2 juvs. (CL 3.5 mm, 3.8 mm), 13 July 2009, hand net, coll. S. Ito & Y. Niimura. Savannakhet Province: Sampling details unknown, 2 ovig. females (CL 8.7 mm, 9.2 mm), 2002. Champasak Province: Det Island, 1 male (CL 7.4 mm), 2 females (CL 6.5 mm, 7.2 mm), 10 July 2009, hand net, coll. S. Ito & Y. Niimura. Diagnosis. Rostrum (Fig. 15 a) barely reaching anterior end of antennal scale, dorsal margin nearly straight, with 8���11 teeth including 2 or 3 placed posterior to orbital margin, ventral margin with 2 or 3 teeth; antennal spine sub-marginal, apex slightly extending beyond antennal lobe, carina supporting antennal spine moderately long; hepatic spine smaller than antennal spine, placed just below level of antennal spine. Sixth abdominal somite 1.4���1.55 times as long as fifth somite, fourth pleuron rounded posteroventrally, that of fifth sub-rectangular; pre-anal carina well marked, sub-triangular in shape. Telson 1.35���1.55 times as long as sixth abdominal somite, ending in short but sharp process, with 2 pairs of ordinary sub-terminal spines and 2 pairs of dorsolateral spines, anterior pair of latter ones situated at mid-length. Antennal scale 0.7���0.75 times as long as carapace, 2.9���3.1 times as long as wide. Epistome (Fig. 15 b) bilobed. First pereopod extending beyond antennal scale by fingers, latter as long as palm. Second pereopods (Fig. 15 a, c) rather slender, sub-equal in length, shorter than total body length, extending beyond antennal scale by distal half of carpus and onwards; merus as long as or slightly longer than carpus, latter as long as or slightly shorter than palm; fingers 0.75���0.9 times as long as palm, cutting edges with about 6 obtuse teeth on proximal part. Third pereopod with propodus (Fig. 15 d) 2.5���3.1 times as long as dactylus, possessing 6���8 spines on posterior margin. Appendix masculina about twice length of appendix interna, with numerous stiff setae on anterolateral margin and mesial surface. Uropod with exopod sub-equal in length or slightly longer than endopod, movable spine on diaeresis (Fig. 15 e) slightly longer than lateral projection. Egg. Eggs oblong, non-eyed eggs measuring 1.1���1.2 x 1.7���1.8 mm. Remarks. Our specimens agreed with the original description of this species, although the Laotian specimens had a comparatively shorter dactylus of the third pereopod. The material examined also resembled M. niphanae, but a proportionately slender and short second pereopods with a naked, smooth carpus distinguishes it from the latter species. Macrobrachium thai also resembles M. tratense, but the rostrum of this species was consistently shorter than that of the latter species, not extending beyond the antennal scale. Distribution. Macrobrachium thai has been recorded from north-eastern and eastern Thailand (Cai et al. 2004) and also in southern Laos (present study)., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 27-28, DOI: 10.5281/zenodo.204065, {"references":["Cai, Y., Naiyanetr, P. & Ng, P. K. L. (2004) The freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea: Decapoda: Palaemonidae). Journal of Natural History, 38, 581 - 649."]}

Macrobrachium yui Holthuis, 1950 (Figs. 16, 17) Palaemon brevicarpus var. heterochirus Yu, 1936: 305, figs. 1, 2. Macrobrachium yui Holthuis, 1950: 211: Liu et al. 1990: 123, fig. 20; Naiyanetr 1998: 34 (list): Cai & Dai 1999: 237: Li & Liang 2002: 708, 715; Cai et al. 2004: 611, fig. 10; Li et al. 2007: 142, fig. 57. Macrobrachium yeti Dang, 1975: 67, fig. 1; 1980: 386, fig. 221. Material examined. Houaphan Province: Et River, Et District, 12 males (CL 10.3���13.5 mm), 13 females (CL 14.0���17.0 mm), 27 Jan 2009, hand net, coll. S. Ito et al. Sayabouri Province: Tributary of Heung River, 6 males (CL 16.2���18.9 mm), 10 females (CL 18.2���26.5 mm), 25 June, 2009, hand net, coll. S. Ito et al. Luang Namtha Province: Mi River, Viengphoukha District, 1 male (16.0 mm), definite data unknown, coll. Somphuthone Phimmachak. Luang Prabang Province: Ou River, Ngoi District, 12 males (CL 24.0��� 35.5 mm), 6 females (CL 22.2 ��� 29.0 mm), 12 Aug 2000, coll. Somboon, Kaenchanh & Tinthip (LARReC C 0001); Ou River, Ngoi District, 2 males (CL 18.0 mm, 20.0 mm), 19 females (CL 15.5���20.5 mm), Sept 2000, coll. O. Lasasimma (LARReC C 0002); Ou River, Ngoi District, 1 male (CL 17.0 mm), 3 females (CL 15.5 -20.0 mm), Feb 2001, coll. O. Lasasimma (LARReC C0003); Ou River, Ngoi District, 7 females (CL 12.5 -19.0 mm), Feb 2001, coll. O. Lasasimma (LARReC C 0005); Ou River, Ngoi District, 2 males (CL 16.5 mm, 19.0 mm), 4 females (CL 16.0���19.0 mm), Feb 2001, coll. O. Lasasimma (LARRec C 0008); Xuang River, Na Pho Village, 4 males (CL 25.8���38.4 mm), Feb 2001, coll. O. Lasasimma (LARReC 0010); Xuang River, Na Pho Village, 10 males (CL 26.8���35.5 mm), 13 females (CL 19.0���30.0 mm), 28 July 2007, trap, coll. S. Ito et al.; mouth of rock cave in Xuang River, Na Pho Village, more than 50 juvs. (CL 1.6���1.8 mm), 6 Nov 2007, trap, coll. S. Ito et al.: mouth of Kok-dua, Ou River, Ngoi District, 4 males (CL 26.5���33.5 mm), 6 females (CL 23.8���26.5 mm), 22 July 2008, coll. S. Ito et al.; Houy-gun, Ou River, Ngoi District, 10 males (CL 24.0���30.0 mm), 23 July 2008, coll. S. Ito et al.; Ken-gun Cave, Khan River, Xieng Ngeun District, 7 males (CL 25.0��� 30.5 mm), 4 females (CL 19.0���23.0 mm), 25 July 2008, hand net, coll. S. Ito et al. Diagnosis. Rostrum (Fig. 16) barely reaching mid-length of third peduncular segment of antennule, dorsal margin weakly rounded and armed dorsally with 8���13 teeth including 3���5, commonly 4, placed posterior to orbital margin, ventrally with 2���5, commonly 2 or 3, teeth; antennal spine sub-marginal, apex extending as far as or slightly beyond antennal lobe; hepatic spine as large as antennal spine, situated posteriorly, somewhat below level of antennal spine. Antennal scale 0.45���0.5 times as long as carapace, slightly less than 2.5 times as long as wide. Sixth abdominal somite slightly longer than fifth; fourth pleuron rounded posteroventrally and fifth one forming sub-acute angle; pre-anal carina sharp, sub-triangular in shape. Telson slightly less than 2 times as long as sixth abdominal somite, posterior margin sub-triangular, with small projection, with 2 pairs of ordinary sub-terminal spines of unequal length, dorsal median margin of telson weakly grooved, with 2 pairs of dorsolateral spines, anterior pair situated at slightly posterior to mid-length. First pereopod extending beyond antennal scale by distal two-thirds of carpus and onwards, fingers sub-equal or slightly shorter than palm. Second pereopods in males (Figs. 16, 17 a) sub-equal or slightly unequal in length; major leg (mostly in left side) extending beyond antennal scale by carpus and onwards; carpus shorter than merus; fingers slightly shorter than palm, with some 20 small teeth on cutting edges; minor leg extending beyond antennal scale by distal one-third of carpus and onwards. Second pereopods in females sub-equal in length, extending beyond antennal scale by distal one-third of carpus and onwards. Third pereopod (Fig. 17 b) with propodus 3.9���4.1 times as long as dactylus, latter somewhat robust basally. Appendix masculina (Fig. 17 c) about twice length of appendix interna, with long stiff setae on anterior margin and also on mesial surface. Uropodal exopod slightly longer than endopod, movable spine present in juveniles (Fig. 17 g), reducing its size with growth, then completely absent in adult specimens (Fig. 17 d). Remarks. Cai et al. (2004) mentioned that, in the early life stages, this species has a movable spine on the diaeresis of the uropodal exopod, although adult specimens lack this character. Their finding is confirmed in our study, as early juveniles in fact have a distinctly longer spine than the lateral projection (Fig. 17 g), which becomes short with growth and is completely lost in specimens larger than 15 mm in carapace length (Fig. 16 d). The appendix masculina starts to develop at about a size of 4���5 mm in carapace length. Unlike other species in the present study, breeding females were not encountered in the open riverine water despite extensive surveys. Due to their relatively high commercial value, M. yui (���Khoung-Bo��� means ���cave prawn��� in the local dialect) has been intensively exploited by local people in northern Laos. Local people catch larger adult specimens using a set net installed at steep streams leading to caves (Fig. 18). Hence, mature individuals of this species were assumed to migrate up to a cave adjoining the main river to spawn. To support this, the junior authors (SI, OL, PS) conducted a diel sampling at a small stream flowing out from a possible spawning cave in the Xuang River, Luang Prabang Province. This survey yielded a large number of early stage juveniles at night (Fig. 17 e���g). In addition, they successfully produced larvae from this prawn in the laboratory from adult females caught in the open waters. These findings indicate that mating of this species had occurred in the open riverine waters before they arrive to the spawning cave. Their unique ecology will be reported elsewhere. Distribution. Macrobrachium yui has been recorded previously from northern Vietnam, Yunnan Province, south-western China, and northern Thailand (see Cai et al. 2004). The present study confirmed its presence in several localities of northern Laos., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 29-32, DOI: 10.5281/zenodo.204065, {"references":["Holthuis, L. B. (1950) The Palaemonidae collected by the Siboga and Snellius Expeditions, with remarks on other species. I. Subfamily Palaemoninae. Siboga-Expeditie, 39 a 9, 1 - 268.","Yu, S. C. (1936) Notes on new fresh-water prawns of the genus Palaemon from Yunnan. Bulletin of the Fan Memorial Institute of Biology (Zoology), 6, 305 - 314.","Liu, J. Y., Liang, X. & Yan, S. (1990) A study of the Palaemonidae (Crustacea Decapoda) from China I. Macrobrachium, Lean- der, and Leandrites. Transactions of the Chinese Crustacean Society, 2, 102 - 133. (in Chinese)","Li, S. Q. & Liang, X. - Q. (2002) Caridean prawns of northern Vietnam (Decapoda: Atyidae, Palaemonidae). Acta Zootaxonomica Sinica, 27, 707 - 716. (in Chinese)","Li, X., Liu, R., Liang, X. & Chen, G. (2007) Crustacea, Decapoda, Palaemonidea. Fauna Sinica, Invertebrate, vol. 44. Science Press, Beijing, 381 pp. (in Chinese)","Dang, N. T. (1975) The identity of North Vietnamese freshwater shrimps and crabs. Journal of Biology-Geology, 13 (3), 65 - 78. (in Vietnamese)"]}

Key to species of Rhopalophthalmus 1 Eyes elongated, longer than antennular peduncle.............................................. R. flagellipes Illig - Eyes moderate in length, falling far short of anterior end of antennular peduncle.................................... 2 2 Carapace without anterior dorsal nodule or discernible only as feeble swelling, if present............................ 3 - Carapace with distinct anterior dorsal nodule................................................................ 8 3 Ten or more spines of antennal sympod arranged in true conical form........................... R. dakini O. Tattersall - Fewer than 10 spines of antennal sympod not arranged in conical form but composed of 1–3 prominent mesial spines flanked usually by a few to several much smaller additional spines, showing notable difference in height between them........... 4 4 Antennal sympod possessing 3 prominent spines; antennal scale more than 7 times length of its width................................................................................................... R. chilkensis O. Tattersall - Antennal sympod possessing 1 or 2 prominent spines; antennal scale utmost 7 or lesser than 7 times length of its width.... 5 5 Telson without discernible waist near base................................................................. 6 - Telson with discernible waist near base.................................................................... 7 6 Antennal sympod bearing 1 prominent mesial spine and 1 small additional spine; carpo-propodus of seventh thoracic endopod composed of 4 sub-segments.......................................................... R. africana O. Tattersall - Antennal sympod bearing 1 longest mesial second spine flanked by shorter most mesial spine and much shorter 5–7 lateral spines: carpo-propodus of seventh thoracic endopod composed of 8–10 sub-segments........... R. philippinensis sp. nov. 7 Antennal sympod bearing 2 prominent mesial spines of sub-equal length flanked by 2 short lateral spines................................................................................................... R. brisbanensis Hodge - Antennal sympod bearing 1 prominent mesial second spine flanked by much shorter most mesial spine and 1–3 short lateral spines................................................................................ R. hastatus sp. nov. 8 Antennal scale distinctly overreaching anterior end of antennular peduncle........................................ 9 - Antennal scale barely reaching or slightly overreaching anterior end of antennular peduncle approximately by length of distal suture............................................................................................. 11 9 Carpo-propodus of seventh thoracic endopod composed of 7 or 8 sub-segments, carpus shorter than entire length of propodus............................................................................... R. terranatalis O. Tattersall - Carpo-propodus of seventh thoracic endopod composed of 4 sub-segments, carpus distinctly elongated, sub-equal to entire length of propodus................................................................................... 10 10 Telson armed laterally with 14–16 moderately long setae, length of posterior series as long as posterior width of telson............................................................................................... R. longipes Ii - Telson armed laterally with 9–12 unusually strong setae, length of posterior series longer than posterior width of telson.......................................................................................... R. armiger sp. nov. 11 Telson with marked constriction near apex.......................................... R. constrictus Panampunnayil - Telson without constriction near apex..................................................................... 12 12 Antennal sympod bearing 5 spines arranged in form of cone, with median spine longest................. R. indicus Pillai - Antennal sympod bearing 2 or 3 prominent spines flanked by a few much smaller lateral spines...................... 13 13 Antennal sympod bearing 3 prominent graduated spines flanked commonly by 2 small lateral spines.... R. egregius Hansen - Antennal sympod bearing 2 prominent spines of sub-equal length flanked commonly by 1 or 2 small lateral spines....... 14 14 Telson with marked basal waist......................................................................... 15 - Telson without basal waist or hardly defined, if present....................................................... 21 15 Inner pair of spinose apical telson setae longer than outer pair................................................. 16 - Inner pair of spinose apical telson setae shorter than outer pair................................................ 17 16 Rostrum well advanced, sub-triangular; rudimentary endopods of eighth thoracopods poorly developed in both sexes, not reaching mid-length of basal plate of exopods................................................ R. tattersallae Pillai - Rostrum obtusely rounded; rudimentary endopods of eighth thoracopods in both sexes moderately developed, extending well beyond mid-length of basal plate of exopod............................................. R. orientalis O. Tattersall 17 Rudimentary endopods of eighth thoracopods in both sexes reaching or extending well beyond distal end of basal plate of exo- pod................................................................................................ 18 - Rudimentary endopods of eighth thoracopods in both sexes falling far short of distal end of basal plate of exopod........ 19 18 Rostrum wide triangular; telson armed laterally with 14 setae; carpo-propodus of seventh thoracic endopod with 3 sub-seg- ments.............................................................................. R. kempi O. Tattersall - Rostrum obtusely rounded; telson armed laterally with 11 setae; carpo-propodus of seventh thoracic endopod with 4 or 5 sub- segments................................................................... R. anishi Panampunnayil & Biju 19 Carpo-propodus of seventh thoracic endopod with 4 sub-segments............... R. murudana Panammupunnayil & Biju - Carpo-propodus of seventh thoracic endopod with 5 or 6 sub-segments.......................................... 20 20 Telson armed laterally with 14–19 setae; rostrum wide triangular...................... R. tropicalis Wooldridge & Mees - Telson armed laterally with 11 or 12 setae; rostrum obtusely rounded.............. R. mumbayensis Panampunnayil & Biju 21 Inner pair of spinose apical telson setae longer than outer pair................................................. 22 - Inner pair of spinose apical telson setae as long as or shorter than outer pair...................................... 23 22 Telson unusually long, posterior end including spinose apical setae extending end of uropodal exopod; rudimentary endopod of male eighth thoracopod poorly developed, reaching utmost to mid-length of basal plate of exopod..................................................................................................... R. longicauda O. Tattersall - Telson moderate in length, posterior end including spinose apical setae falling far short of end of uropodal exopod; rudimen- tary endopod of male eighth thoracopod elongated, extending beyond basal plate of exopod........... R. macropsis Pillai 23 Telson armed laterally with fewer than 10 setae on length of distal two-fifths; carpo-propodus of seventh thoracic endopod with 5 sub-segments......................................................... R. vijayai Panampunnayil & Biju - Telson armed laterally with more than 15 setae on length of distal two-thirds; carpo-propodus of seventh thoracic endopod with 7 or more sub-segments............................................................................... 24 24 Carpo-propodus of seventh thoracic endopod with 7 sub-segments; antennal scale more than 5 times as long as wide....................................................................................... R. mediterraneus Nouvel - Carpo-propodus of seventh thoracic endopod with 9–11 sub-segments; antennal scale less than 5 times as long as wide............................................................................. R. tartessicus Vilas-Fernández et al.

Macrobrachium sirindhorn Naiyanetr, 2001 (Fig. 13) Macrobrachium sirindhorn Naiyanetr, 2001: 610, figs. 1, 2, pl. 1; Cai et al. 2004, 638, figs. 21, 22. Material examined. Vientiane Province: Pang River, Kasi District, 3 males (CL 10.8 ���16.0 mm), 1 female (CL. 7.5 mm), 2 ovig. females (CL 11.0 mm, 11.7 mm), 22 May 2008, hand net, coll. S. Ito et al.; Song River, Vang Vieng District, 1 male (CL 14.6 mm), 4 females (CL 10.5���12.5 mm), 1 ovig. female (CL 11.2 mm), 22 Dec 2007, hand net, coll. S. Ito et al.; Kasi District, 2 females (CL 11.6 mm, 12.8 mm), 29 Jan 2008, coll. local children & S. Ito; Kasi District, 9 males (CL 10.3���15.7 mm), 1 female (CL 10.3 mm), 4 ovig. females (CL 10.0��� 10.8 mm), 30 Jan 2009, hand net, coll. S. Ito et al.; Kasi District, 3 males (CL 6.1���8.2 mm), 2 females (CL 7.0 mm, 7.5 mm), 4 juvs. (CL 5.4���5.5 mm), 30 Jan 2009, hand net, coll. S. Ito et al.; Kasi District, 22 males (CL 6.6 ���16.0 mm), 20 female (CL 6.5���8.9 mm), 10 ovig. females (CL 8.8 ���10.0 mm), 3 juvs. (CL 5.3 ���6.0 mm), 30 Jan 2009, hand net, coll. S. Ito et al. Diagnosis. Body medium-sized and moderately robust (Fig. 13 a). Rostrum (Fig. 13 a) slightly directed ventrad, barely reaching to slightly overreaching antennular peduncle, 0.45���0.55 times as long as carapace, dorsal margin weakly convex, with 10 or 11 teeth including 3���5, commonly 4, placed posterior to orbital margin (occupying about 30���40 % of total carapace length), ventrally with 1���3, normally 2, teeth. Antennal lobe moderately developed, antennal spine marginal, rather long, extending well beyond antennal lobe; hepatic spine smaller than antennal spine, situated backwardly, distinctly below level of antennal spine. Abdomen (Fig. 13 a) with sixth somite 1.35���1.5 times as long as fifth, with sharp pre-anal carina; pleuron of fourth somite rounded posteroventrally and that of fifth angulated: first 3 sternal plates each with well developed median tooth. Telson 1.35���1.6 times as long as sixth abdominal somite, posterior end triangular, with 2 pairs of ordinary sub-terminal spines, of which lateral pair much smaller than mesial pair, 2 pairs of dorsolateral spines present, anterior pair of which placed near mid-length. Antenna with scale about 0.55���0.65 times as long as carapace, 2.7 ���3.0 times as long as wide, lateral margin weakly convex, distolateral spine strong, falling distinctly short of anterior margin. Epistome (Fig. 13 b) with distinct anteromedian process (tri-lobed). First pereopods overreaching antennal scale by distal one-third of carpus and onward, fingers as long as or slightly shorter than palm. Second pereopods (Fig. 13 a, d���i) in adult males distinctly unequal in size, somewhat dissimilar in shape, palm and fingers commonly covered with velvety setae on both sides: major pereopod extending fully beyond antennal scale by chela, and its length sub-equal or slightly shorter than total body length; merus inflated at mid-length, about twice length of carpus, with scattered small spinules on distolateral part and occasionally with velvety setae on mesial margin; carpus nearly cup-shaped, about 1.5 times or slightly more than its maximum height, occasionally covered with velvety setae on distal and distolateral parts; palm slightly inflated, as long as or slightly longer than merus; fingers not gaped when closed, 0.55���0.85 times as long as palm (proportionately longer in females), with 9���14 teeth on cutting edges; minor leg extending fully beyond antennal scale by chela; merus slightly longer than palm, latter as long as fingers, often bearing velvety setae on ventral margins but setae occasionally sparse or even absent (setae usually absent in females); ischium with or without velvety setae on ventral margin. Third pereopod (Fig. 13 j) slightly extending beyond antennal scale, propodus 2.5���3.1 times as long as dactylus, armed with 4 or 5 spines on ventral margin; dactylus moderately robust, anterior margin with a row of stout setae and also ventral margin with a few sets of setae. Appendix masculina (Fig. 13 k) about twice length of appendix interna, with numerous stiff setae on anterolateral margin and mesial surface. Uropodal expod (Fig. 13 b) sub-equal in length to endopod, movable spine on diaeresis distinctly shorter than lateral projection. Egg. Non-eyed eggs oblong, medium-sized, measuring 1.10���1.30 x 1.65���1.80 mm. Remarks. Previous researchers (Naiyanetr 2001; Cai et al. 2004) have stressed, on the basis of Thai specimens, that this species has velvety setae on the ventral margin of the merus of the second pereopods. In our specimens, however, this feature showed considerable variation from one specimen to another from complete absence to dense setae (see Fig. 13 g���i), and females usually did not have setae on the merus and ischium. The number of teeth on the cutting edges of the fingers was slightly larger in Laotian specimens than in those reported in Thailand (9���14 vs. 8���10 teeth). However, we do not regard these differences as significant at species level. Macrobrachium sirindhorn belongs to the ��� M. pilimanus (De Man, 1879) ��� species group, in which 16 species have been recognised to date (Cai et al. 2004; Wowor & Short 2007). Morphologically, M. sirindhorn shows close resemblance to M. hirsutimanus (Tiwari, 1952), which is known from Myanmar and Thailand (Cai et al. 2004). According to the published data, this species distinctively differs from the latter by the possession of a tri-lobed epistome instead of a bi-lobed one (see Cai et al. 2004). Moreover, this species differs from M. hirsutimanus in the following specific features: 1) the propodus of the third pereopod of M. sirindhorn is proportionately longer than M. hirsutimanus (0.25���0.31 times of dactylus vs. 0.20���0.25); 2) posterior margin of the dactylus with a few tufts of setae as opposed to a naked one; 3) cutting edges of the fingers of the second pereopods bear smaller number of teeth ( 10). These differences are minor but may warrant the distinction between the two populations. Macrobrachium sirindhorn also resembles M. ahkowi Chong & Khoo, 1987 and M. malayanum (Roux, 1934). The latter two species differ from M. sirindhorn in the following specific features: M. ahkowi has a rostrum bearing more dorsal teeth (12���17, usually 14 or 15, teeth vs. ��� 11), while M. malayanum possesses a remarkably large tooth (or teeth) on the fingers of the second pereopod (Chong & Khoo 1987 a, b). Our preliminary analysis of the mitochondrial gene (16 S rRNA) has demonstrated that M. sirindhorn forms a distinct clade from M. amplimanus, M. dienbienphuense, and M. eriocheirum by the presence of substantial substitutions in several nucleotides (Imai et al. unpubl. data). Of 20 specimens examined, 25 % of them were right-handed (right second pereopod larger than left one) (Hanamura et al. unpubl. data). Distribution. Macrobrachium sirindhorn has been recorded from northern Thailand (Cai et al. 2004). This species was commonly captured from several streams around Vang Vieng in central Laos., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 23-24, DOI: 10.5281/zenodo.204065, {"references":["Wowor, D. & Short, J. W. (2007) Two new freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea: Decapoda: Palaemonidae) from the Kelian River, East Kalimantan, Indonesia. The Raffles Bulletin of Zoology, 55, 77 - 87.","Tiwari, K. K. (1952) Diagnosis of new species and subspecies of the genus Palaemon Fabricus (Crustacea: Decapoda). Annals and Magazine of Natural History, (12) 5, 27 - 32.","Roux, J. (1934) New freshwater decapod crustaceans from the Malay Peninsula. Bulletin of the Raffles Museum, 9, 28 - 34.","Chong, S. S. C & Khoo, H. W. (1987 a) Macrobrachium malayanum (Roux, 1934) stat. nov. (Decapoda, Palaemonidae) as a synonym of M. geron Holthuis, 1950, with notes on its distribution. Journal of Natural History, 21, 903 - 913.","Chong, S. S. C. & Khoo, H. W. (1987 b) Macrobrachium ahkowi nom. nov., a replacement name for Macrobrachium johnsoni Chong & Khoo, 1987, preoccupied by Macrobrachium johnsoni Ravindranath, 1979 (Decapoda: Caridea: Palaemonidae). Zoologische Mededelingen, 61, 561 - 562."]}

Macrobrachium superbum (Heller, 1862) (Fig. 14) Palaemon superbus Heller, 1862: 528. Macrobrachium superbum: Holthuis 1950: 139; Liu et al. 1990: 105, Fig. 3; Cai & Dai 1999: 221, fig. 7; Li et al. 2007: 134, fig. 53. Material examined. Houaphan Province: Sim River, Vieng Xay District, 10 males (CL 5.4 ���8.0 mm), 25 July, 2008, hand net, coll. S. Ito et al. Diagnosis. Rostrum (Fig. 14 a) extending slightly beyond antennular peduncle but not overreaching antennal scale, dorsal margin nearly straight, with 10���13 teeth including 2 or 3 situated posterior to orbital margin, ventral margin with 2 or 3 teeth; antennal lobe moderately developed, antennal spine marginal, extending slightly beyond antennal lobe; hepatic spine smaller than antennal spine, placed posteriorly, slightly below level of antennal spine. Sixth abdominal somite about 1.5 times as long as fifth one, pre-anal carina hardly visible; first 2 abdominal sternites with marked media projection but not on third; fourth pleuron rounded posteriorly, that of fifth sub-rectangular but with no projection/point. Telson 1.3���1.4 times as long as sixth abdominal somites, posterior end triangular with 2 pairs of ordinary sub-terminal spines, 2 pairs of dorsolateral spines, anterior pair of latter ones placed around mid-length. Antennal scale 0.7���0.8 times as long as carapace, about 3 times as long as wide. Epistome bi-lobed. Third maxilliped reaching end of first segment of antennular peduncle, distal segment slightly shorter than penultimate. First pereopod overreaching antennal scale by distal part of fingers, latter as long as or slightly shorter than palm. Second pereopods (Fig. 14 a, b) sub-equal in length and similar in shape, length shorter than total body length and extending beyond antennal scale by distal 1 / 5 ��� 1 / 3 of carpus and onwards; merus slightly shorter than carpus, latter shorter than chela, 1.6 ���2.0 times as long as palm; fingers 1.2���1.4 times as long as palm, no tubercles or teeth present on cutting edges. Third pereopod with propodus (Fig. 14 c) 2.3���2.7 times as long as dactylus, with 6 or 7 somewhat widely set spines on posterior margin. Appendix masculina (Fig. 14 d) slightly less than twice length of appendix interna, with numerous stiff setae on mesial surface. Uropodal exopod sub-equal in length to endopod, movable spine on diaeresis (Fig. 14 e) longer than lateral projection. Remarks. According to published literature (Zhang & Sun 1981; Liu et al. 1990; Cai & Dai 1999), M. superbum often co-occurs with M. nipponense in various localities of China. Specimens assigned to this species closely resemble young M. nipponense. Among specimens captured in the Houaphan Province in north-eastern Laos, those with the palm of the second pereopod shorter than the fingers without tooth on its cutting edges were referred to as M. superbum. Other specimens of comparable body sizes having the palm of sub-equal length to or slightly longer than fingers as well as the cutting edges possessing small tubercles at base were attributed to M. nipponense. It is most probable that M. superbum have been introduced accidentally in Laos in association with aquaculture activities together with M. nipponense. Distribution. Macrobrachium superbum was established from south-eastern China near Shanghai and has then been recorded throughout China (Li et al. 2007)., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 26-27, DOI: 10.5281/zenodo.204065, {"references":["Heller, C. (1862) Neue Crustaceen gesammelt wahrend der Weltumseglung der K. K. fregate Navora: Zweiter vorlaufiger Bercht. Verhandlungen des Kaiserlich-Koniglichen Zoologische-Botanischen Gesellschaft in Wien, 12, 519 - 528.","Holthuis, L. B. (1950) The Palaemonidae collected by the Siboga and Snellius Expeditions, with remarks on other species. I. Subfamily Palaemoninae. Siboga-Expeditie, 39 a 9, 1 - 268.","Liu, J. Y., Liang, X. & Yan, S. (1990) A study of the Palaemonidae (Crustacea Decapoda) from China I. Macrobrachium, Lean- der, and Leandrites. Transactions of the Chinese Crustacean Society, 2, 102 - 133. (in Chinese)","Li, X., Liu, R., Liang, X. & Chen, G. (2007) Crustacea, Decapoda, Palaemonidea. Fauna Sinica, Invertebrate, vol. 44. Science Press, Beijing, 381 pp. (in Chinese)","Zhang, J. S. & Sun, K. Y. (1981) Studies on the freshwater shrimps from the middle and lower Yangtze River. Chinese Journal of Zoology, 4, 2 - 6. (in Chinese)"]}

Macrobrachium amplimanus Cai & Dai, 1999 (Fig. 2) Macrobrachium amplimanus Cai & Dai, 1999: 231, figs. 14–16; Cai et al. 2004: 637. Macrobrachium dienbienphuense: Li et al. 2007: 84 (part). Material examined. Luang Prabang Province: Ou River, Ngoi District, 3 males (CL 13.4–17.8 mm), Feb 2001, coll. O. Lasasimma (LARReC 0004); Ou River, Ngoi District, 1 ovig. female (CL 10.6 mm), Feb 2001, coll. O. Lasasimma (ex LARReC 0006); Ou River, Ngoi District, 1 male (CL 14.3 mm), Feb 2001, coll. O. Lasasimma (ex LARReC 0007); Xuang River, Na Pho Village, St. 2, 1 male (CL 12.8 mm), 2 females (CL 9.4 mm, 10.3 mm), 28 Jan 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 3, 1 male (CL 17.7 mm), 29 Mar 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 2, 2 males (CL 13.5 mm, 15.0 mm), 1 ovig. female (CL 9.8 mm), 27 Apr 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 1, 2 males (CL 11.5 mm, 13.5 mm), 3 ovig. females (CL 10.0– 12.5 mm), 24 May 2008, hand net, coll. S. Ito et al.; Xuang River, Na Pho Village, St. 1, 1 male (CL 17.0 mm), 24 May 2008, hand net, coll. S. Ito et al. Champasak Province: Khone Island, 2 males (CL 9.5 mm, 11.3 mm), 2 females (CL 11.3 mm, 14.0 mm), 2 ovig. females (CL 9.5 mm, 10.1 mm), 11 July 2009, set net, coll. S. Ito & Y. Niimura. Diagnosis. Rostrum (Fig. 2 a) reaching mid-length to anterior end of antennular peduncle or occasionally extending slightly beyond antennular peduncle, 0.38–0.52 times as long as carapace, dorsal margin weakly convex, directed slightly ventrad, with dorsally 10–13 teeth including 3–6 placed posterior to orbital margin, ventral margin with 1–3 teeth; antennal lobe moderately developed, antennal spine marginal, apex reaching to or extending slightly beyond antennal lobe; hepatic spine slightly smaller than antennal spine, placed distinctly below level of antennal spine. Abdomen with sixth somite 1.30–1.50 times as long as fifth, pre-anal carina well marked and highly elevated; pleuron of fourth somite rounded posteroventrally, that of fifth somite somewhat angulated. Telson 1.4–1.7 times as long as sixth abdominal somite, posterior end sub-triangular with 2 pairs of ordinary sub-terminal spines and 2 pairs of dorsolateral spines, anterior pair of which spines are placed just posterior to mid-length. Epistome (Fig. 2 b) with anteromedian projection (tri-lobed), but median projection occasionally hardly noticeable. Antennal scale 0.5–0.6 times as long as carapace, 2.6–2.9 times as long as wide. Third maxilliped barely reaching anterior end of antennal scale, distal segment slightly shorter than penultimate one. First pereopod extending beyond antennal scale by half to full length of carpus and onwards, fingers about 0.7 times as long as palm. Second pereopods distinctly unequal in length, covered with long velvety setae on palm, fingers, and, occasionally, on anterior part of carpus: major leg (Fig. 2 a, c, d) as long as or slightly longer than total body length (from the apex of the rostrum to the posterior end of the telson), extending beyond antennal scale by carpus and onwards; merus as long as palm, 2.3 –3.0 times as long as high, with minute spinules particularly on lateral and anterior surfaces; carpus cup-shaped, about half length of merus and again as long as or slightly shorter than anterior high, with minute spinules particularly on lateral and dorsal surfaces, marked transverse groove present along anterodorsal margin; palm 0.7 –1.0 times as long as fingers, 1.6–1.9 times as wide; fingers with narrow gape when closed, with 13–17 teeth on cutting edges; minor leg extending beyond antennal scale by carpus and onwards, palm as long as or slightly shorter than merus, 0.6–0.9 times as long as fingers, 1.6–2.2 (normally Appendix masculina (Fig. 2 f) about twice length of appendix interna, with numerous stiff setae on anterolateral margin as well as mesial surface. Uropodal exopod sub-equal in length to endopod, movable spine on diaeresis (Fig. 2 g) shorter than lateral projection. Egg. Non-eyed eggs measuring 0.9–1.25 x 1.3–1.5 mm. Remarks. Li et al. (2007) suggested that Macrobrachium amplimanus, as well as M. eriocheirum Dai, 1984 and M. pilosum Cai & Dai, 1999, should be junior synonyms of the morphologically variable M. dienbienphuense Dang & Nguyen, 1972. In fully grown males examined in this study, the palm of the major second pereopod for specimens referred to M. amplimanus is noticeably greater than that attributed to M. dienbienphuense and M. eriocheirum (cf. Cai & Dai 1999), and the structure of the carpus of the second pereopod also differed (Table 2). To confirm this, the 16 S rRNA mitochondrial gene was sequenced for typical specimens. The results of analyses support the recognition of three genetically different groups (Fig. 5). Hence, M. amplimanus, M. dienbienphuense, and M. eriocheirum are regarded as good species (see also “Remarks” under M. dienbienphuense). Macrobrachium amplimanus and M. eriocheirum occur in abundance in the Xuang River, Luang Prabang Province, northern Laos, with M. amplimanus normally found in faster-running streams than M. eriocheirum, suggesting that the two species use different microhabitats within the same river (Ito pers. obser.). Cai & Dai (1999) and Cai et al. (2004) noted that M. amplimanus has a comparatively short rostrum, falling slightly short of the mid-length of the third segment of the antennular peduncle. The rostrum of the Laotian specimens, however, showed some minor variations in length as it fully reaches the mid-length to slightly overreach the anterior end of the antennular peduncle. Moreover, our specimens consistently had a pair of distoventral spines at least on the propodus of the third pereopod. In specimens collected from the Champasak Province, southern Laos, the median lobe on the epistome was poorly developed (somewhat similar to bi-lobed form) and, as a consequence, superficially resembled M. hirsutimanus (Tiwari, 1952) sensu Cai et al., 2004. However, these authors described M. amplimanus as having a proportionately longer propodus of the third pereopod (2.7–3.1 times the length of dactylus vs. 2.0– 2.5 in M. hirsutimanus), a poorly developed median tooth on the third abdominal somite (vs. well developed), a sharp preanal carina (vs. rounded ridge), and comparatively small-sized eggs (0.9 –1.0 x 1.25–1.4 mm vs. 1.0– 1.25 x 1.4–1.7 mm). As such, the present materials should also be referred to M. amplimanus. TABLE 1. Specimens of the Macrobrachium dienbienphuense species groups used for DNA analyses. * Macrobrachium rosenbergii and M. lanchesteri were chosen as out-groups. Examined so far for Laotian specimens, 44 % of specimens (N= 46) were right-handed (right second pereopod larger than left one) (Hanamura et al. unpubl. data). Distribution. Yunnann Province, south-western China, Thailand, and Laos (Cai & Dai 1999; Cai et al. 2004; present study).

Rhopalophthalmus egregius Hansen, 1910 (Figs. 1���3) Rhopalophthalmus egregius Hansen, 1910: 49, pl. 6, fig. 3 a���k, pl. 7, fig. 1 a���d. ��� W. Tattersall 1915: 151 (at least in part). ��� O. Tattersall 1957: 87, fig. 1 a. ��� O. Tattersall 1960: 169. Rhopalophthalmus phyllodus Murano, 1988: 293, figs. 1, 2. Not Rhopalophthalmus egregius ��� Nakazawa 1910: 255, pl. 8, figs. 12, 22 (= R. orientalis O. Tattersall, 1957). ��� W. Tattersall 1915: 151 (in part= R. chilkensis O. Tattersall, 1957. ��� W. Tattersall 1921: 408 (= R. orientalis O. Tattersall, 1957). ��� W. Tattersall 1922: 457 (in part= R. kempi O. Tattersall, 1957). ��� W. Tattersall 1936: 147 (= R. armiger sp. nov.). ��� W. Tattersall 1940: 330 (= R. dakini O. Tattersall, 1957). ��� O. Tattersall 1952: 161, figs. 3, 4 (= R. terranatalis O. Tattesall, 1957). ��� O. Tattersall 1955: 87 (=? R. terranatalis O. Tattersall, 1957). ��� Pillai 1957: 2, fig. 1 (= R. tattersallae Pillai, 1961) Material examined. Syntypes. Sangkapoera roads, Bawean Island, Java Sea, Indonesia: 1 male abdomen (without carapace and cephalic appendages) (BL> 10 mm), 1 ovig. female (BL ca. 10 mm); 12 m depth, Siboga Expedition (ZMUC CRU- 6334). Thailand. Surat Thani: 7 females (BL ca. 10���10.1 mm), 17 ovig. females (BL ca. 9.4���12 mm), 5 abdomens (all more or less damaged); 16 Oct 1978, coll. T. Rojanasarumpakit (Topotypic specimens of R. phyllodus Murano, 1988) (NSMT Cr 21207). ��� Bang Plasoi, Chonburi: 5 males (BL ca. 6.5���9 mm), 1 female (damaged), 1 juv. (BL 4 mm), 2 abdomens (NSMT Cr 21208); ��� 1 male, 1 ovig. female, 2 abdomens (all damaged) (NSMT Cr 21209); 22 Aug 1980, coll. Marine Fisheries Laboratory, Department of Fisheries, Thailand. ��� Klong Don Sak, Surat Thani: 1 female (damaged); 14 Apr 1987, coll. Marine Fisheries Laboratory, Department of Fisheries, Thailand (NSMT Cr 21210). ��� Sapum Bay, Phuket Is.: 15 males (BL ca. 6.5���10 mm), 15 females (BL ca. 7���11 mm), 1 ovig. female (BL ca. 11.5 mm), 19 juvs. (BL ca. 4���6.5 mm), 4 abdomens; 19 Feb 1980, coll. Marine Fisheries Laboratory, Department of Fisheries, Thailand (NSMT Cr 21211). Singapore. 1 male (BL ca. 9.0 mm), 9 juvs. (BL 3.5 ���5.0 mm); St. B 44 2 (c) (NHM 1964.1. 21 5446 / 5558). Malacca Strait. 2 males (BL ca. 8.2, 8.7 mm), 1 female (BL 7.0 mm), 1 juv. (BL 4.0 mm); St. B 51 1 (c) (NHM 1964.1. 21 5546 / 6558). ��� 1 male (BL ca. 8.0 mm), 3 females (BL ca. 6.5��� 9 mm), 6 juvs. (BL ca. 3���3.5 mm); St. B 51 1 (c) (NHM 1964.1. 21 5558 / 6563). Malaysia. Matang mangrove estuary: 5 males (BL 6.3���8.8 mm), 1 female (BL 6.0 mm), 2 juvs. (BL 4.0, 5.0 mm); St. 2, 4˚ 50.6 ' N, 100 ˚ 35.3 ' E, sledge, 4.5 m deep, 8 Apr 2005, coll. Y. Hanamura (NSMT Cr 21201). ��� 1 male (BL ca. 8 mm); off shore of St. 4 (4 ˚ 51.4 ' N, 100 ˚ 32.9 ' E), sledge, 2 m depth, 14 June 2006, coll. Y. Hanamura (NSMT Cr 21202). ��� Merbok mangrove estuary: 2 males (BL 6.2, 8.8 mm), 1 female (BL 7.7 mm), 4 ovig. females (BL 9.1���10.5 mm); St. A, 5 ˚ 40.1 ' N, 100 ˚ 22.2 ' E, sledge, 1.5 m depth, 14 Oct 2004, coll. Y. Hanamura (NSMT Cr 21203). ��� 25 males (BL 5.3���8.8 mm), 17 females (BL 5.5���8.1 mm), 17 ovig. females (BL 8.6 ���12.0 mm); St. A, 5 ˚ 40.1 ' N, 100 ˚ 22.2 ' E, sledge, 0.8 m depth, 16 Dec 2004, coll. Y. Hanamura (NSMT Cr 21204). ��� 4 males (BL 7.0��� 9.3 mm), 6 females (BL ca. 6���9.5 mm); St. A, 5 ˚ 40.1 ' N, 100 ˚ 22.2 ' E, sledge, 2.1 m depth, 16 Dec 2004, coll. Y. Hanamura (FRI Cr 005). Indonesia. Segara Anakan, Java: 4 males (BL 7.7���8.8 mm), 1 female (BL 8.7 mm), 4 ovig. females (BL ca. 8.0��� 9.5 mm); mid-night, surface tow with larva net, 19 Sept 1988, coll. Mulyadi (NSMT Cr 21198). ��� Cilacap Bay, southern coast of central Java: 14 males (BL 6.5���9.6 mm), 9 females (BL ca. 5.8���11 mm), 4 ovig. females (BL ca. 8.5���11.7 mm), 17 juvs. (BL ca. 2.4���5.5 mm); 24 Aug 1992, coll. Mulyadi (NSMT Cr 21199). ��� Tegal, central Java: 1 female (BL 7.7 mm), 30 juvs. (BL 2.7���4.5 mm), 2 abdomens; 3 June 1994, coll. Mulyadi (NSMT Cr 21200). India. Chilka Lake, Orissa: 2 males (BL ca. 10, 10.5 mm), 8 ovig. females (BL ca. 9���12 mm); presented by Indian Museum (NHM 1914.12.15.11��� 30). Aberrant form (having 4 stout spines on either side of antennal sympod). Malaysia: Merbok mangrove estuary: 1 ovig, female (BL 10.2 mm); St. A, 5 ˚ 40.1 ' N, 100 ˚ 22.2 ' E, sledge, 3���4 m depth, 11 Jan 2005, coll. Y. Hanamura (NSMT Cr 21205). ��� 1 male (BL 6.1 mm); St. A, 5 ˚ 40.1 ' N, 100 ˚ 22.2 ' E, sledge, 1.5 m depth, 17 May 2005, coll. Y. Hanamura (NSMT Cr 21206). ��� 1 ovig. female (BL 8.2 mm), 1 male (damaged); St. A, 5 ˚ 40.1 ' N, 100 ˚ 22.2 ' E, sledge, 0.9���1.2 m depth, 20 Dec 2005, coll. Y, Hanamura (FRI Cr 006). Description. Body moderately robust (Fig. 1 a). Anterior dorsal part of carapace between postorbital spines (Figs. 1 b���d) weakly produced, forming wide, semicircular or sub-triangular rostral plate; postorbital spine, extending as far as anterior end of rostral plate, carina supporting spine feeble and short; cervical sulcus marked dorsally and laterally around anterior one-third of carapace; anterior dorsal median nodule (Figs. 1 a, b) placed immediately behind cervical sulcus small but well defined, posterior nodule situated close to posterior dorsal margin; posterior dorsal margin of carapace excavate, leaving last 3 thoracic somites uncovered in dorsal aspect; cheeks evenly concave; antero-lateral spine sharp, extending as far as anterior end of rostral plate. Eyes sub-pyriform (Figs. 1 c, d), length of cornea slightly shorter than eye stalk. Antennules sexually dimorphic (Figs. 1 g, h); male first segment of peduncle slightly longer than combined length of anterior 2 segments, bearing several long, inwardly curving setae along lateral margin (slightly deformed in figure due to artifact); second segment shortest, shorter than wide, with a few short to moderately long setae along mesial and lateral margins; third segment as long as wide, possessing a few to several hooked sensory setae on mesial margin and several long setae around disto-mesial part; lateral flagellum swollen at basal part, forming male lobe and its mesial margin hirsutid densely with long hair. Female antennular peduncle more slender than that in males, with first segment distinctly longer than combined length of anterior 2 segments, bearing several long, inwardly curving setae along lateral margin (slightly deformed in figure due to artifact); second segment shortest and shorter than wide; third segment slightly longer than wide, without short sensory setae at disto-mesial part but with several moderate to long setae. Antenna (Figs. 1 a���d, i, 3 b) with scale extending slightly beyond end of antennular peduncle, slightly more than 4 times as long as wide in female and approximately 5 times as long as wide in male; disto-lateral spine sharp, extending slightly beyond anterior margin of lamella; distal suture present; sympod normally possessing 3 long graduated spines increasing in length from mesial to lateral and usually 2 small spines situated near base of longest spine. Labrum truncated anteriorly, without median spine. Mouth parts typical of genus (see Murano 1988; figs. 1 d���h, as R. phyllodus). Thoracic appendages: third thoracic endopod (Figs. 2 a, b) slightly stouter than fourth one, with carpo-propodus of 3���5 articles, fourth to sixth thoracic limbs (Figs. 2 c, d) similar in shape, carpo-propodi of endopods with 4��� 6, most commonly 5, articles, but infrequently 7 articles. Seventh thoracic endopod (Figs. 2 e, f, 3 d) extending well beyond cervical sulcus of carapace, its carpo-propodus composed of 5���7, infrequently 8, articles and longest distoventral setae bearing up to 7 stout setules around middle part, followed by feeble but distinct denticles on ventral margin. Rudimentary eighth thoracic endopod in males (Figs. 2 g, 3 c) 3 -segmented, normally curving anteriorly, falling short of end of basal plate of exopod when extended; second segment short, bearing several long setae, third segment elongated, with or without short terminal seta. Rudimentary eighth thoracic endopod in females (Fig. 2 h) reaching or falling just short of distal end of basal plate, un-articulated but often showing incipient articulation-like structure at mid-length and 1 small seta around mid-length. Abdominal somites (Fig. 1 a) rounded dorsally, first 5 somites sub-equal in length, sixth somite 1.2���1.4 times as long as fifth one; first somite of male rounded ventrally to form pleuron, with shallow excavation at anterior part. Pleopods in males (Figs. 2 i���k) biramous: first pleopod with endopod un-articulated, possessing several short, marginal setae, exopod articulated; second pleopod with exopod elongated, composed of about 13 articles, basal articles each bearing long seta, distal 5 articles comparatively long and enire except for terminal one bearing pair of apical setae and proportionately long sub-apical seta, endopod multi-articulated; third to fifth pleopods similar in shape with multi-articulated endopod and exopod of sub-equal length. Pleopods in females (Figs. 2 l���n) un-articulated, increasing in length on posterior somites. Uropod (Fig. 1 f) with 2 -segmented exopod and endopod; exopod longer than endopod, distal segment slightly shorter than half-length of basal one; endopod with basal segment about 2.5 times as long as distal one, possessing stout seta on ventral surface posterior to statocyst. Telson (Figs. 1 e, 3 a) 1.2���1.4 times as long as sixth abdominal somite and slightly more than 2.5 times as long as basal width, reaching articulation of uropodal endopod and stout apical spinose setae of telson extending beyond articulation of uropodal exopod by about two-thirds of its length, abruptly narrowing near base to form waist and slightly broadened near mid-length, then gradually narrowing distally; rounded posterior margin of telson with four stout spinose setae, mesial pair being shorter than lateral one, and their tip curving outwards, setules of distal telson setae becoming broader and consequently take on somewhat leaf-like form particularly in distal ones, lateral margin with 13���16, commonly 14 or 15, setae, increasing in length posteriorly and bearing minute 1���4 microscopically small setules on posterior part of larger posterior setae but such setules usually not present in short anterior setae. Body length. Largest recorded male: BL 10.5 mm, largest ovigerous female: BL ca. 12 mm. Egg size. Females of BL 9.2���10.8 mm carrying 5���9 embryos, stage I embryos (eggs) oblong in shape, 0.60��� 0.75 mm along longer axis (N= 11). Colour. Entire body semi-transparent when alive. In fresh specimens collected from west coasts of Peninsular Malaysia with telson possessing basal semi-circular red chromatophore and slightly larger, elliptical red one at distal one-third to one-fourth. Remarks. Rhopalophthalmus egregius was established by Hansen (1910) on the basis of materials collected off Bawean Island in the Java Sea, Indonesia. Later, several authors reported this species from various localities worldwide due to somewhat insufficient original descriptions coupled with superficia inter-specific resemblance within the genus Rhopalophthalmus. Tattersall (1957) examined considerable numbers of specimens collected from various localities of the entire geographical range of Rhopalophthalmus and suggested that the following features could be useful in discriminating species within the genus: 1) the presence/absence of the dorsal median nodules on the carapace, 2) the ornamentation of spines on the antennal sympod, 3) the number of the carpo-propodal articles of the thoracic endopods, 4) the shape of the rudimentary eighth thoracic endopod, and 5) the structure and armature of the telson. Tattersall (1957) also re-examined the type materials of R. egregius housed in the Amsterdam Museum and supplemented the following diagnostic features for the species: 1) the presence of the anterior dorsal median nodule on the carapace, 2) the antennal sympod with three graduated stout spines, 3) the carpo-propodus of the third to seventh thoracic endopod with 4���6 articles, and 4) the lateral posterior pair of spinose setae of the telson slightly longer than the inner pair (see also Ii, 1964). Nevertheless, the exact nature of R. egregius has remained obscure for mysid researchers. We were able to examine the syntype specimens, which are deposited in the Zoological Museum of Copenhagen University. These syntypes were more or less damaged (one female and one male without anterior body part), but we could observe several key features. In the female syntype with the carapace, the anterior median nodule is less developed, represented only by an obtuse elevation. This nodule, however, is often hardly visible in damaged specimens of Rhopalophthalmus. In contrast, this nodule is usually found in non-type specimens referred to this species. The antennal sympod of the female syntype possesses three stout graduated spines and two additional small spines (Fig. 3 b), of which the latter character was not reported by Tattersall (1957). The seventh thoracic endopod of the syntype appears to have a six-segmented carpo-propodus, each segment with long seta bearing several rather long setules, followed by several denticles near the apex (Fig. 3 d). Furthermore, the short setules of the apical telson setae are more or less flat and leaf-shaped rather than jagged, particularly the distal ones, and the lateral setal series of the telson were also furnished with microscopically small setules, particularly the posterior ones (Fig. 3 a). All of these features are shared with the type specimens of R. egregius and R. phyllodus Murano, 1988, and a notable number of additional specimens having the combination of these features have been captured from the coastal waters around Java Island, Indonesia, the Gulf of Thailand, the west coast of the Malay Peninsula, and across Chilka Lake in eastern India. Based on these observations, we concluded R. phyllodus to be a junior synonym of R. egregius. Although we found several specimens with four large spines on one side of the antennal sympods (see Fig. 1 j), the spine arrangement on the antennal sympod was found to be consistent through ontogenetic stages in the observed species of Rhopalophthalmus. Rhopalophthalmus egregious shows a similarity to R. chilkensis O. Tattersall, 1957 in having three stout spines on the antennal sympod, and these two species may co-occur in Chilka Lake. As reported by Tattersall (1957), R. egregius differs from the Indian species in having the anterior dorsal nodule on the carapace (absent in R. chilkensis), a more slender antennal scale that is seven times as long as it is wide (about five times in R. chilkensis), and the mesial pair of the spinose apical telson setae that are shorter (longer in R. chilkensis) than the lateral pair. Taylor (2008) reported R. egregius from the east coast of Australia. However, these Australian specimens have subsequently been determined to be R. brisbanensis Hodge, 1963 (Taylor pers. com.). The identity of Colosi���s (1920) specimens from the south-western Pacific remains uncertified. Distribution. Known with certainty from Indonesia, Gulf of Thailand, Singapore, Malacca Strait, and Chilka Lake in India (Hansen 1910; Tattersall 1957, 1960; Murano 1988; present study). Habitat. Rhopalophthalmus egregius is one of the three most abundant species of the genus in the mangrove brackish water system of north-western Peninsular Malaysia, where it had a tendency to occur in abundance in the mouth area rather than the middle to upper reaches of the estuarine river (Hanamura et al. 2007: as Rhopalophthalmus sp. 3)., Published as part of Hanamura, Yukio, Murano, Masaaki & Man, Alias, 2011, Review of eastern Asian species of the mysid genus Rhopalophthalmus Illig, 1906 (Crustacea, Mysida) with descriptions of three new species, pp. 1-37 in Zootaxa 2788 on pages 2-8, DOI: 10.5281/zenodo.207815, {"references":["Hansen, H. J. (1910) The Schizopoda of the Siboga Expedition. Siboga-Expeditie, 37, 1 - 77, pls. 1 - 12.","Tattersall, W. M. (1915) Mysidacea. Fauna of Great Lake. Memoirs of the Indian Museum, 5, 149 - 161.","Tattersall, O. S. (1957) Report on a small collection of Mysidacea from the Sierra Leone Estuary together with a survey of the genus Rhopalophthalmus Illig and a description of a new species of Tenagomysis from Lagos, Nigeria. Proceedings of the Zoological Society of London, 129, 81 - 128.","Tattersall, O. S. (1960) Report on a small collection of Mysidacea. Proceedings of the Zoological Society of London, 135, 165 - 181.","Murano, M. (1988) Mysidacea from Thailand with descriptions of two new species. Crustaceana, 55, 293 - 305.","Nakazawa, K. (1910) Notes on Japanese Schizopoda. Annotationes Zoologicae Japonenses, 7, 246 - 261, pl. 8.","Tattersall, W. M. (1921) Mysidacea, Tanaidacea and Isopoda. Zoological results of a tour in the Far East. Memoirs of the Asiatic Society of Bengal, 6, 403 - 443, pls. 15 - 17.","Tattersall, W. M. (1922) Indian Mysidacea. Records of the Indian Museum, 24, 445 - 504.","Tattersall, W. M. (1936) Mysidacea and Euphausiacea. Scientific Reports of the Great Barrier Reef Expedition, 1928 - 1929, 5, 143 - 176.","Tattersall, W. M. (1940) Report on a small collection of Mysidacea from the coastal waters of New South Wales. Records of the Australian Museum, 20, 327 - 340.","Tattersall, O. S. (1952) Report on a small collection of Mysidacea from estuarine waters of South Africa. Transactions of the Royal Society of South Africa, 33, 153 - 187.","Tattersall, O. S. (1955) Mysidacea. Discovery Reports, 28, 1 - 190.","Pillai, N. K. (1957) Pelagic Crustacea of Travancore. II. Schizopoda. Bulletin of the Central Research Institute, University of Travancore, Trivandrum, 5, 1 - 28.","Pillai, N. K. (1961) Additions to the Mysidacea of Kerala. Bulletin of the Central Research Institute, University of Kerala, Trivandrum, 8, 15 - 35, pls. 1 - 6.","Ii, N. (1964) Mysidae. Fauna Japonica. Biogeographical Society of Japan, Tokyo. 610 pp.","Taylor, M. D. (2008) Spatial and temporal patterns of habitat use by three estuarine species of mysid shrimp. Marine and Freshwater Research, 59, 792 - 798.","Hanamura, Y., Siow, R. & Chee, P. E. (2007) Abundance and spatio-temporal distribution of hyperbenthic crustaceans in the Merbok and Matang mangrove estuaries, Malaysia. JIRCAS Working Report, 56, 35 - 41."]}

Macrobrachium lanchesteri (De Man, 1911) (Fig. 7) Palaemon paucidens: Lanchester 1901: 568, pl. 33, fig. 4 (not De Haan). Palaemon (Eupalaemon) Lanchesteri De Man, 1911: 264 Macrobrachium lanchesteri: Holthuis 1950: 139; Chong & Khoo 1988: 196, figs. 1���3; Ng 1995: 252; Cai & Ng 2002: 77, fig. 19; Cai et al. 2004: 586. Material examined. Luang Prabang Province: Ou River, Ngoi District, 11 males (CL 3.5 ���8.0 mm), 11 females (CL 6.5���7.5 mm), 8 ovig. females (CL 6.0���8.0 mm), 12 Aug 2000, coll. Somboon & Kaenchan; Pho stream, Na Pho Village, St. 5, 1 male (CL 6.5 mm), 28 Apr 2007, hand net, coll. S. Ito et al.; Pho stream, Na Pho Village, St. 5, 1 male (CL 7.0 mm), 30 Apr 2007, hand net, coll. S. Ito et al.; Pho stream, Na Pho Village, St. 5, 3 males (CL 7.2 - 8.0 mm), 1 female (CL 11.0 mm), 6 ovig. females (CL 9.0��� 10.2 mm), 26 July 2007, hand net, coll. S. Ito et al.; paddy field, Na Pho village, 2 females (CL 6.9 mm, 15.4 mm), 25 Jan 2008, hand net, coll. S. Ito et al. Vientiane Province: Pang River, Kasi District, 1 female (CL 7.8 mm), 29 Jan 2008, coll. local children. Vientiane Capital: Sivilay, 5 females (CL 4.5 ���6.0 mm), 1 ovig. female (CL 7.3 mm), 4 Aug 2007, coll. staff of NADC; Poxai Village, 2 males (CL 6.5, 6.6 mm), 1 female (CL 5.5 mm), 3 Aug 2007, coll. school children; Nanga Village, 2 males (CL 5.1 mm, 6.9 mm), 3 ovig. females (CL 6.1���7.8 mm), 17 Aug 2007, coll. school children; Nong Niew Market, 2 males (CL 4.5 mm, 5.6 mm), 3 females (CL 4.2���9.4 mm), 2 ovig. females (CL 7.8 mm, 9.4 mm), 31 Aug 2007, coll. H. Ikenoue; Nardi Village, 2 males (CL 6.0, 6.5 mm), 22 Sept 2007, coll. school children & H. Ikenoue; Nakha Village, 1 male (CL 6.8 mm), 2 females (CL 6.2 mm, 7.8 mm), 18 Nov 2007, coll. school children & H. Ikenoue; fish pond, NADC, Xuang River, 8 females (CL 5.8���7.8 mm), 7 Dec 2007, coll. H. Ikenoue: fish pond, NADC, Xuang River, 10 males (CL 4.0��� 8.5 mm), 28 females (CL 4.2���10.8 mm), 10 ovig. females (CL 3.9���10.5 mm), 3 juv. (CL 1.8 mm), 18 Jan 2008, hand net, coll. Y. Hanamura & S. Morioka; Tham Village, 4 females (CL 6.6 ���8.0 mm), 1 ovig. female (CL 7.2 mm), 8 Dec 2007, coll. school children & H. Ikenoue; fish pond, NADC, Xuang River, 4 males (CL 4.0��� 4.2 mm), 3 females (CL 4.4���5.3 mm), 30���31 June 2008, coll. H. Ikenoue (Id. by K. Hayashi). Champasak Province: Det Island, 3 males (CL 5.5���5.8 mm), 2 females (CL 7.5 mm, 8.0 mm), 21 July 2009, set net, coll. Y. Niimura; Det Island, 4 males (CL 8.8 ���10.0 mm), 6 females (CL 6.3 ���13.0 mm), 18 females (CL 8.2���12.2 mm), 21 July 2009, set net, coll. Y. Niimura. Diagnosis. Rostrum (Fig. 7 a) straight or weakly curving dorsad, barely reaching or extending slightly beyond antennal scale, armed dorsally with 5���10, commonly 7 or 8, teeth including 1 or 2 situated posterior to orbital margin and 0���2 placed near apex, ventral margin with 2���6, commonly 3���5, teeth; antennal spine marginal, extending well beyond antennal lobe: hepatic spine as large as antennal spine, placed posteriorly, just below level of antennal spine. Sixth abdominal somite about twice as long as fifth, pre-anal carina indistinct but represented by obtuse ridge. Telson approximately 1.2 times as long as sixth abdominal somite, ending in sharp median projection, with 2 pairs of ordinary sub-terminal spines, 2 pairs of dorsolateral spines, anterior dorsal pair of latter ones placed at midlength of telson. Antennal scale 0.8 ���1.0 times as long as carapace. Second pereopods (Fig. 7 a, b) slender, short, both legs similar in form and shorter than body, extending beyond antennal scale by slightly more than chela and onward; carpus slightly less than 1.5 times as long as chela; palm longer than fingers, latter with small tuberculate tooth near basal part. Third pereopod (Fig. 7 c) with propodus 2.1��� 2.5 times as long as dactylus. Appendix masculina (Fig. 7 d) slightly more than twice length of appendix interna, with somewhat sparsely scattered stiff setae on anterolateral margin as well as mesial surface. Exopod of uropod distinctly longer than endopod, movable spine on diaeresis (Fig. 7 e) as long as or slightly shorter than lateral projection. Egg. Eggs relatively larger in number, measuring about 0.6 x 0.9 mm in non-eyed eggs. Remarks. The taxonomic status of M. lanchesteri has been reviewed by several researchers (Chong & Khoo 1988; Cai & Ng 2002; Cai et al. 2004). In our observation, the second pereopods also showed some variations in the length of the carpus, owning possibly to ontogenetic growth, and smaller specimens tended to have a proportionately longer carpus than that observed in adults. Breeding females bear smaller-sized, numerous eggs, and this is one of the important characteristics distinguishing this species from M. kistnense (Tiwari, 1952) and M. tiwarii Jalihal, Shenoy & Sankolli, 1988. Distribution. Macrobrachium lanchesteri has been recorded with reasonable certainty from Peninsular Malaysia, Thailand, and Myanmar as well as from southern China and Java, and Indonesia (cf. Cai & Ng 2002; Cai et al. 2004). This species, one of the most common species in Laos, is frequently captured in ponds, paddy fields, and slow-flowing streams along the Mekong River system., Published as part of Hanamura, Yukio, Imai, Hideyuki, Lasasimma, Oulaytham, Souliyamath, Pany & Ito, Sayaka, 2011, Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Laos, pp. 1-37 in Zootaxa 3025 on pages 13-14, DOI: 10.5281/zenodo.204065, {"references":["De Man, J. G. (1911) On two new species of decapod Crustacea. Notes from the Leyden Museum, 33, 223 - 232.","Lanchester, W. F. (1901) On the Crustacea collected during the \" Skeat \" Expedition to the Malay Peninsula, together with a note on the genus Actaeopsis. Proceedings of the Scientific Meetings of the Zoological Society of London, 1901, 534 - 574, pls. 33, 34.","Holthuis, L. B. (1950) The Palaemonidae collected by the Siboga and Snellius Expeditions, with remarks on other species. I. Subfamily Palaemoninae. Siboga-Expeditie, 39 a 9, 1 - 268.","Chong, S. S. C. & Khoo, H. W. (1988) The identity of Macrobrachium lanchesteri (De Man, 1911) (Decapoda, Palaemonidae) from Peninsular Malaysia and Singapore, and a description of its first zoea. Crustaceana, 54, 196 - 206.","Ng, P. K. L. (1995) Freshwater decapod crustaceans (Potamidae, Palaemonidae) of Temengor Forest Reserve, Hulu Perak, Malaysia. Malayan Nature Journal, 48, 249 - 257.","Cai, Y. & Ng, P. K. L. (2002) The freshwater palaemonid prawns (Crustacea: Decapoda: Caridea) of Myanmar. Hydrobiologia, 487, 59 - 83.","Tiwari, K. K. (1952) Diagnosis of new species and subspecies of the genus Palaemon Fabricus (Crustacea: Decapoda). Annals and Magazine of Natural History, (12) 5, 27 - 32.","Jalihal, D. R., Shenoy, S. & Sankolli, K. N. (1988) Freshwater prawns of the genus Macrobrachium Bate, 1868 (Crustacea, Decapoda, Palaemonidae) from Karnataka, India. Records of the Zoological Survey of India, Occasional Paper, 112, 1 - 74."]}

Hanamura, Yukio, Kase, Tomoki (2004): Heteromysoides (Crustacea: Mysidacea: Heteromysini) from a submarine cave on Grand Cayman, the Caribbean Sea: descriptions of a new and a rare species. Journal of Natural History 38 (17): 2145-2152, DOI: 10.1080/00222930310001625914, URL: http://dx.doi.org/10.1080/00222930310001625914

Hanamura, Yukio, Koizumi, Noriyuki, Sawamoto, Shozo, Siow, Ryon, Chee, Phaik Ean (2008): Reassessment of the taxonomy of Mesopodopsis orientalis (Tattersall, 1908) (Crustacea, Mysida) and proposal of a new species for the genus with an appendix on M. zeylanica Nouvel, 1954. Journal of Natural History 42 (37-38): 2461-2500, DOI: 10.1080/00222930802277608, URL: http://dx.doi.org/10.1080/00222930802277608