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From samples of deep-water zooplankton obtained in the Gulf of California, an undescribed species of the genus Hyperoche Bovallius was collected. The new species is similar to Hyperoche medusarum Kroyer and Hyperoche luetkenides Walker. It differs from its congeners mainly by the strong, large chela of pereopod 2 and the absence of processes or denticles along the posterior distal margin of same structure. It was collected at a depth of 1136 m as a symbiont of the bathypelagic hydromedusa Chromatonema erythrogonon (Bigelow). The amphipod remained grasped to the medusa subumbrellar cavity. Seven other associations are known between hyperiids and jellies in the Gulf of California, most from the epipelagic layer. This is the only deep-living species of Hyperoche known.

Embryonic, larval, and juvenile development of a small Indian cyprinid, Horadandia atukorali, is described from laboratory-reared specimens. The eggs, measuring 0.7–0.8 mm in diameter, were demersal, almost spherical in shape, transparent and unpigmented, with a pale yellow yolk without oil globules. Hatching occurred 47–54 h after fertilization at 26.3–27.5°C. The newly hatched larvae, measuring 2.3–2.6 mm in body length (BL) with 16 + 13 = 29 myomeres, had no melanophores, except on the eye, a single melanophore occurring on the lower margin, and xanthophores surrounding the pupil. The yolk was completely absorbed at 3.0 mm BL. Notochord flexion was initiated at 4.0 mm BL and finished at 4.4 mm BL. Aggregate numbers of all fin rays were completed at 8.0 mm BL. Squamation was initiated at 6.4 mm BL and completed at 9.5 mm BL. Although the eggs of Horadandia atukorali resembled those of other small danionin species, including Aphyocypris chinensis, Chela dadiburjori, Danio rerio, Devario malabaricus, and Hemigrammocypris rasborella, they differed from those of Danio rerio and Devario malabaricus in having a narrower perivitelline space. The larvae and juveniles of Horadandia atukorali were also similar to those of the latter five species in general morphology, especially in the presence of a melanophore on the lower margin of the eye at hatching, as in C. dadiburjori. However, the early life stage morphology of Horadandia atukorali differed from the other danionin species in having a conical yolk sac at hatching, no cement organ on the forehead in the yolk-sac larval stage, a divided gas bladder in the flexion larval stage, two dark lateral streaks on the head and chevron-like melanophores on the ventral body surface from the preflexion to postflexion larval stages, and xanthophores on the eyes at hatching.

An alpheid shrimp, Alpheus pacificus Dana, 1852, is recorded from Korea for the first time based on the specimens collected from the intertidal zone in Jeju-do, Korea. A. pacificus is readily distinguished from A. malabaricus by having the inferior shoulder on the lateral face of the major chela with a very deep, rounded notch, and by the simple, non-spatulate dactylus of the third pereopod. The Korean Alpheidae now includes 19 species representing 7 genera.

Semi-terrestrial ghost crabs, Ocypode jousseaumei, are active on sheltered beaches at low tide. Each tidal cycle, males construct courtship burrows that spiral according to the handedness of the crab's major chela. Burrows are over-dispersed since residents prevent other crabs from excavating burrows too close and some emerging crabs abandon their burrows. Other wandering crabs may enter courtship burrows eliciting threatening displays or fights which are more severe in like-handed crab social interactions. Sometimes residents are evicted. The details of vibrational/acoustic signalling of male O. jousseaumei are reported, including the first complete description of stridulation. The approach of crabs of any species or sex elicits increased rapping behaviour by residents, but close passage or entry elicits stridulation from within the burrow. Rapping is probably a signal to advertise residents’ location while stridulation is used for burrow defence. It is probable that male crabs’ vibrational/acoustic sign...

Embryonic, larval, and juvenile development of an Indian cyprinid fish, Chela dadiburjori, is described from laboratory-reared specimens. The eggs, measuring 0.7–0.9 mm in diameter, were demersal, almost spherical in shape, transparent and unpigmented, with a pale yellow yolk and no oil globule. Hatching occurred 50–61 h after fertilization at ca. 27°C. The newly hatched larvae, measuring 2.4–2.6 mm in body length (BL), had melanophores on the body with 14–16 + 14–17 = 29–31 myomeres. Two dark transverse bands on the ventral body surface and one melanophore on the lower margin of the eye in newly hatched larvae were diagnostic. Additionally, a cement organ for adhering to objects was present on the forehead of yolk sac larvae

Leg 5 development is described for 10 species from 10 genera in 6 families of centropagoidean calanoid copepods. Segment homologies are inferred from the order in which arthrodial membranes, setae, and attenuations are added to ramal segments during late copepodid development. Among centropagoidean males, the grasping chela on the side opposite the male genital pore develops in three different ways. The fixed part of the chela may be a ventral attenuation of the basis, or of the proximal exopodal segment, or of the middle exopodal segment, suggesting that a male leg 5 chela is not a synapomorphy of the Centropagoidea because nonhomologous segments make up the convergent morphology. In like manner, a grasping subchela on the side opposite the male genital pore is expressed in three different ways: basis plus proximal, middle and distal exopodal segments; basis plus proximal and distal exopodal segments; or basis plus distal exopodal segment; so nonhomologous segments also result in a convergent su...

Biomass determination of hermit crabs is difficult without destroying the gastropod shells of the specimens. To minimize the number of animals destroyed in the process of determining this parameter over time, the chela-height vs. body-weight relationship of each of the three hermit-crab species was recorded in different areas of the North Sea. Linear regression was carried out for the species Pagurus bernhardus, P. pubescens, and P. prideauxi, in order to allow calculations of individual biomass on the basis of the chela height of specimens. No spatial differences in the chela-height vs. body-weight relationship were found for single species, whereas the relationship between the three species differed significantly. Thus, for each species a regression function is given, valid for the whole North Sea, that allows estimations of the body weight of the three hermit-crab species from measuring the chela height alone.

The present study was conducted to investigate the effect of eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA) on the survival and the occurrence of molting failure to megalops of mud crab Scylla serrata larvae fed enriched Artemia. Survival rate, intermolt period, carapace width at the first crab stage, ratio of chela to carapace length at the fifth zoeal stage and the occurrence of molting failure to megalops were observed. Mud crab larvae were reared in 1-L plastic beakers and fed with Artemia enriched at five different levels of EPA (0.31% to 1.36% EPA; referred to as E25, E50, E75 and E100) or four different levels of DHA (0.75–0.95% EPA and 0.49–1.38% DHA; referred to as D25, D50, D75 and D100). As a negative control, larvae were fed Artemia enriched with oleic acid (OA). Mud crab larvae fed Artemia containing low (0.41–0.45% EPA and trace DHA) or high (1.36% and 0.95% EPA and 0.16% and 1.38% DHA) amounts of EPA and DHA showed a significantly lower survival rate and prolonged intermolt period (P

Certain joints in the pedipalps of scorpions and sun-spiders lack extensor muscles but have elastic transarticular sclerites that store energy during flexion and return energy as elastic recoil during extension. This study quantifies the extension torque contributed by elastic recoil and hydraulic pressure in the chela (tibia-tarsus) and femur-patella joints of scorpions and the patella-tibia and tibi- tarsus joints of sun-spiders. Extension torque was measured as isolated joints were cycled through a natural range of angles and angular velocities by a computer controlled stepper motor. Resilience (efficiency of elastic energy return) of transarticular sclerites in the absence of internal fluid pressure was about 60% in scorpion joints and 80% in sun-spider joints. Elastic torque increased almost linearly with flexion angle in most joints except in the scorpion chela, where elastic torque decreased rapidly as the fully closed joint began to open, increased gradually and then decreased again near the fully open position. Hydraulic pressure contributed more to extension of pedipalpal joints of scorpions than those of sun-spiders. Our results indicate that mechanical properties of a ''passive'' transarticular sclerite can be changed by altering internal fluid pressure and by capitalizing on the sclerite's intrinsic viscoelasticity.

The uniramous ‘great appendages’ of several arthropods from the Early to Middle Cambrian are a characteristic pair of pre-oral limbs, which served for prey capture. It has been assumed that the morphological differences between the ‘great-appendage’ arthropods indicate that raptorial antero-ventral and anteriorly pointing appendages evolved more than once in arthropod phylogeny. One set of Cambrian ‘great-appendage’ arthropods has, however, very similar short antero-ventral appendages with a peduncle of two segments angled against each other (elbowed) and with stout distally or medio-distally directed spines or long flexible flagellate spines on each of the four distal segments. Moreover, the head appendages of all these forms comprise the ‘great appendages’ and three pairs of biramous limbs. To this set of taxa we can add a new form from the Lower Cambrian Maotianshan Shale of southern China, Haikoucaris ercaiensis n. gen. and n. sp. It is known from three specimens, possibly being little abundant in the faunal community. It can be distinguished from all other taxa by the prominence of the proximal claw segment of its ‘great appendages’ and by only three distal spines (one on each of the distal segments). The similarity of the short, spiky ‘great appendages’ of Haikoucaris with the chelicera of the Chelicerata leads us to hypothesize that this particular type of ‘great appendages’ was the actual precursor of the chelicera. Homeobox gene and developmental data recently demonstrated the homology between the antenna of ateloceratans and the antennula of crustaceans on one side and the chelicera of chelicerates on the other. To this we add palaeontological evidence for the homology between the chelicerae of chelicerates and the ‘short great appendages’ of certain Cambrian arthropods, which leads us to hypothesize that the evolutionary path went from the ‘short great appendages’, by progressive compaction, toward the chelicera with only a two-spined chela. The new form from China is regarded as the possible latest offshoot, whereas the other ‘great appendages’ arthropods with similar short grasping limbs were derivatives of the stem lineage of the crown-group Chelicerata. Consequently, the chelicera with a chela with one fixed and one mobile finger is an autapomorphy of the crown group of Chelicerata, whereas a raptorial, but more limb-like antenna, with more distal spine-bearing segments, characterized the ground pattern of Chelicerata. Further taxa having ‘great appendages’, including the large Anomalocarididae, are also discussed in the light of their possible affinities to the Chelicerata and possible monophyly of all of these arthropods with raptorial anterior appendages.

Synopsis A new specimen of Palaeoburmesebuthus grimaldii Lourenco, 2002, recently described from Cretaceous (Albian) Burmite, is reported. This is more complete than the holotype consisting of five scattered, unequal parts: a complete metasoma with an attached partial mesosoma bearing a visible stigma, a right pedipalp chela and three leg fragments. Comparisons to extinct and extant lineages of scorpions are made, although the partially observable trichobothrial pattern of the pedipalp chela precludes definitive family placement. The relative position of the fragments and the severe damage they have suffered imply that it was dismembered by a predator and provides the oldest evidence of scorpions being preyed upon by other animals.

Three new species of Macrobrachium Bate, 1868, i.e., M. gurudeve, M. jayasreei, and M. kunjuramani, collected from the rivers Kabbini and Bhavani (east flowing rivers of Kerala State) are described here in detail. The most important diagnostic features of the species are: in M. gurudeve, the rostrum is broad with 7-9 upper (2 post-orbital) and 3-5 ventral teeth, characteristically arranged; telson broad, dorsal pairs of spines situated at the distal third, and inner distal pair of spines very short; 2nd cheliped with carpus shorter than chela, and fingers ¾ of palm; appendix masculina with 1 long and 4 short distal spinous setae and 13 and 4 stiff lateral setae in two rows; uropodal exopod without accessory spine. In M. jayasreei, the rostrum is very slender, with 7-8 (1 or 2 post-orbital) and 4-5 ventral teeth, maximum width of the rostrum at the level of 2nd ventral tooth, and distal ventral tooth widely separated from the remaining ones; telson slender with 2 pairs of dorsal spines at distal half, and inner distal pair very long and slender; 2nd pair of pereiopods with carpus longer than chela and fingers about half as long as palm, as well as palm longer than half carpus; appendix masculina with 6 distal, stiff spinous and 9 lateral stiff setae, uropodal exopod without accessory spines. In M. kunjuramani, rostrum broad with 7-9 (2 post-orbital) dorsal and 4-5 ventral teeth, characteristically arranged; cephalothorax shorter than rostrum; telson slender with dorsal spines situated at the distal half, and inner distal pair of spines slender; 2nd pereiopods with carpus longer than chela, fingers half as long as palm; appendix masculina with 3 distal, stiff spinous and 6 lateral stiff setae; uropodal exopod with accessory spine. The colouration of the three species is also described.

The new species Brachistosternus paulae is described. This is the southernmost species of the genus, occurring in southern Patagonia in Santa Cruz Province. It can be distinguished from all the other species of the genus by the presence of only 4 ventral trichobothria on the pedipalpal chela, and by the shape of the hemispermatophore, in which the cylindrical apophysis is shorter than the laminar apoph- ysis; all internal spines are absent, except for the row of spines, which in some specimens is vestigial. This species can not be included in any of the known subgenera due to its trichobothrial pattern; never- theless it is closer to the subgenus Leptosternus on the basis of its remaining morphology. A key for the species of the genus in the country is provided together with some data on them. The hemispermatophores of the three subgenera are compared and two maps detailing the distribution of the species in the country are provided.

The effects of the multiple autotomy on epibiosis infestation on embryos, on the survival of embryos, and on brooding care behaviour were examined in females ofCyrtograpsus angulatus, a south-western Atlantic intertidal and subtidal crab. The population ofC. angulatusin Mar Chiquita, a coastal lagoon, presents a high incidence of limb autotomy. Newly laid embryos of both healthy and autotomized females were immediately colonized by bacteria and filamentous fungi, peritrichid ciliates, and few small animal species, while detritus was accumulated. The periphery of the embryo mass was more infested by epibionts and accumulated more detritus than the central region. Multiple autotomy in femaleC. angulatusincreased the epibiosis and detritus accumulation in embryos and pleopods, decreased the chance of embryos to complete their development. The following behaviours related to brooding care were observed in both healthy and autotomized females: standing, chela and pereiopod probing, abdominal flapping, pleopod beating and maxilliped beating. However, the time devoted to standing and abdominal flapping was significantly higher in healthy and autotomized females, respectively. Brooding care behaviour in non-ovigerous females and in females with early and late embryos, suggests the presence of different signalling systems that trigger them. We propose that multiple autotomy modifies brood care, decreases the success of embryonic development and, consequently, reduces the contribution of autotomized females (approximately 30% of the potentially reproductive females ofC. angulatusin Mar Chiquita) to the following generation.

Summary 1We examined the link between handling time (Th), adopted feeding techniques, profitability curves and prey size selection to further understand the constraints that influence bivalve prey selection in shore crabs (Carcinus maenas L.). 2Blue mussels (Mytilus edulis L.) of different sizes were used as prey. Prey size was generalized to the ratio between mussel width and major chela length (MW : MCL) and prey profitability standardized to the ratio between prey mass eaten per unit breaking time and predator mass (1/h Tb). 3Crabs either crushed the mussel with their claws or opened the mussel using the more time-consuming cutter technique. The latter technique was employed above a critical MW : MCL ratio (0·24). This threshold appeared to coincide with the ratio where prey profitability is maximal. 4When a range of prey sizes were offered simultaneously, an observed MW : MCL ratio (0·14–0·16) turned out to be lower than the predicted optimal MW : MCL ratio (0·16–0·22) and lower than the MW : MCL ratio where the first crab switched feeding techniques (0·16). Crabs preferred a MW : MCL ratio of 0·16 over the optimal ratio of 0·24 when given dichotomous choices between different MW : MCL ratios. 5Although larger and more profitable mussels can be crushed, we suggest that crabs select small crushable mussels to prevent claw wear and tear. Claw damage has a considerable effect on mating success and hence on an individual's fitness. Risk of claw damage may thus be of greater importance to a foraging shore crab than energy maximization.

We examined Ohio and Mississippi River specimens of Orconectes that had been identified previously as O. placidus and collected new specimens or examined types of Orconectes luteus, O. placidus, O. forceps, O. medius, and O. rusticus from Illinois and other states. Our analyses revealed the presence of three species of Orconectes in the Ohio and Mississippi rivers, Orconectes luteus, O. placidus, and O. sp. (undescribed), based on chela morphometrics, gonopods, carpal spines, chela denticles, and life colors. All the Mississippi River records of O. placidus were O. luteus, and many of the Ohio River records of O. placidus were O. n. sp. Distinguishing characteristics for all three species, along with an addition to the dichotomous key to Illinois decapods, were included. The ranges of O. luteus, O. placidus, and O. n. sp. in Illinois were amended. Several problems were noted with the syntypes of O. placidus such as erroneous locality, misidentification, and mixing of specimens between localities. The ratio dactylus length/palm mesial margin length, which has been considered a distinguishing characteristic between O. forceps and O. placidus, was invalidated as a useful discriminator for these species, whereas presence or absence of a distomedian carpal spine was reliable. We consider Orconectes luteus and O. n. sp. native inhabitants of Illinois, and the latter species likely occurs in Kentucky portions of the Ohio River as well.

The new species Bothriurus jesuita is described. This species belongs to the bonariensis species group and is closely related to Bothriurus chacoensis Maury & Acosta 1993 from which it can be distinguished by its thicker and taller chela and because of it is almost 30% larger. It can be distinguished from Bothriurus bonariensis (C.L. Koch 1842) because it has an apical filament on the basal lobe of the right hemispermatophore and because the frontal ridge reaches the frontal fold. Bothriurus jesuita has been collected in the northern region of Corrientes Province and in Misiones Province in an area that belongs to the “Paranaense” Phytogeographic Province. RESUMEN En el presente trabajo se describe a Bothriurus jesuita sp. nov., esta especie pertenece al grupo bonariensis y se encuentra muy relacionada con Bothriurus chacoensis Maury y Acosta 1993; puede diferenciarse de esta por poseer una pinza mas alta y robusta, y por ser casi un 30% mas grande. Puede diferenciarse de Bothriurus bonariensis (...

The European green crab, Carcinus maenas, is an invasive species in eastern North America and has the potential to significantly impact wild and aquaculture shellfish in the southern Gulf of St. Lawrence, Canada. To examine potential predation effects on local shellfish and assess the appropriateness of extrapolating results from studies conducted elsewhere, the morphometry of chelae from a recently established population of C. maenas in Nova Scotia was examined for comparison with the presumed founding (European) population, and forces generated by the chelae over a range of crab sizes were estimated. The Nova Scotia population was found to be morphologically very similar to European populations with respect to chela structure. Force generation by the chelae was found to scale with isometry in the female crab and with positive allometry in the male. Estimated forces compare well with previously reported forces, and force generation is calculated to increase in a nonlinear manner proceeding from the chela tips proximally toward the fulcrum. The calculated forces generated by the chelae are clearly sufficient for outright crushing of some shells (e.g., Mya arenaria), even for small crabs, but appear to be too low for crushing those of other molluscs. There is a complex interplay between gape and maximum force along the length of the dactyl that allows great variability in force application, and thus also in the size of prey consumed and prey-handling behaviour. We suggest that for such a lever system, the gape angle of the chelae, which does not change with crab size, is optimal with respect to the resultant force generated.

A new genus and new species of pandalid shrimp, Calipandalus elachys, is described on the basis of the specimens from Taiwan, Solomon Islands, and New Caledonia in the western Pacific Ocean. Calipandalus new genus resembles Bitias Fransen, 1990, in the lack of an exopod on the third maxilliped, the short rostrum, and the presence of arthrobranchs on the four anterior pereopods. It is distinguished from Bitias by the presence of tegumental scales, the moderately spaced, fixed dorsal teeth on the rostrum proper, the short antennular stylocerite, and the peculiar structures of the mandibular palp and the chela of the second pereopod. The new species also bears similarity to particular species of Plesionika Bate, 1888, although the absence of an exopod on the third maxilliped sets the new species apart from Plesionika.

Procambarus (Austrocambarus) cavernicola, a new species of stygobitic crayfish known only from Gabriel Cave, Oaxaca, Mexico, is described. The new species is characterised by a body that lacks pigmentation, except for small purple spots on the eyes; with small setae on the tip of the eye; elongated chelipeds, with the surface of chela covered with small tufts of short setae; first pleopod of form I male with mesial process elongated and conical, triangular central projection, reduced cephalic process and cephalic shoulder forming convex border; annulus ventralis with preannular plate covered with short setae, postannuluar plate oval-shaped, with blunt tubercles. The new species is morphologically similar to other stygobite members of the subgenus Austrocambarus from the Oaxaca–Veracruz area, whose relationships are discussed. The distributions and levels of adaptation to the subterranean environment of 16 cave-inhabiting taxa of Procambarus in Mexico are reviewed.

Three new species of Pontella, P. bonei, P. kleini, and P. vervoorti are described and illustrated from specimens collected in three areas of Indonesian coastal waters, and their relationships to related species are discussed. P. kleini, collected from Cilacap Bay, central Java, which belongs to the P. labuanensis-group of Mulyadi (1997) is distinguishable from other species of this group by a combination of characters of the genital complex without any processes, the Re's of P5, and the asymmetrical caudal rami (CR) in the female; and the rostrum with double convex lenses, the Re's of the P5 with 2 subequal thumbs, and the anterior surface of the chela of the right P5 being without any processes in the male. P. bonei and P. vervoorti, which were collected from Bone Bay, south Celebes, and Semarang Harbour, central Java, belong to the P. danae-group of Mulyadi (1997) and are distinguished from other species of this group by the extreme asymmetry in the CR; P5 is virtually naked and asymmetrical, the terminal segment of left P5 is bulb-shaped, the apex has 3 round-tipped spines which are becoming shorter outwards, and 1 flagellar process. Trois nouvelles especes de Pontella, P. bonei, P. kleini et P. vervoorti sont decrites et illustrees grâce a des specimens provenant de trois zones des eaux cotieres indonesiennes, et leurs relations avec les especes affines sont discutees. P. kleini, trouvee dans la baie de Cilacap au centre de l'ile de Java, appartient au groupe P. labuanensis de Mulyadi (1997) et se distingue des autres especes du groupe par une combinaison de caracteres: le complexe genital depourvu de processus, l'exopodite de la P5 et les rames furcales (CR) asymetriques chez la femelle et chez le mâle: le rostre a deux lentilles convexes, l'exopodite de la P5 avec deux processus digitiformes subegaux et la surface anterieure de l'aculeus de la P5 droite sans aucun processus. P. bonei et P. vervoorti, recoltees dans la baie de Bone, dans le sud de l'ile de Celebes et dans le port de Semarang, a Java, appartiennent au groupe P. danae de Mulyadi (1997). Elles se distinguent des autres especes du groupe par l'extreme asymetrie des rames furcales, les P5 pratiquement nues et asymetriques, le segment terminal de la P5 gauche en forme de bulbe, l'apex portant trois epines a bouts arrondis et devenant plus courtes vers l'exterieur et un processus flagelliforme.

McLaughlin, P.A. 2003. A new genus and species of hermit crab (Decapoda: Anomura: Paguridae) from seamounts off south-eastern Tasmania, Australia. Memoirs of Museum Victoria 60(2): 229‐236. A new and highly variable species, representing a new genus of hermit crabs, is described and illustrated. In addition to the morphological changes in shape and armature of the chelipeds associated with growth in Bythiopagurus macrocolus, gen. nov., sp. nov., this species exhibits a singular development of the left chela that may be an adaptation to its specialised habitat among colonies of the stony coral Solenosmilia variabilis Duncan. The similarities seen among the genera Bythiopagurus, gen. nov., Michelopagurus McLaughlin and Icelopagurus McLaughlin appear the be superficial and convergent; Bythiopagurus appears phylogenetically related to the Pylopaguropsis group of genera characterised by 13 pairs of bi- or quadriserial gills.

A study of the rock falls conditions of an area in the city of Lubango (Angola) was carried out. The upper parts of the studied slopes are constituted by whitish and grayish quartzites and pink, brown or reddish sandstone from the Chela Group of the Precambrian age. Debris deposits can be found at the toe of the slope. The slope movements are more frequent during the rainfall period, which run from October through April. A lithological and volumetric characterization of the rock fall blocks present on the study area was carried out. The software program Rocfall of the Rocscience packages was used to study the rock fall paths. The rocks location, mass and velocity as well as the properties of the slope material were defined and the rock falls trajectories were studied. The possible rock fall trajectories on the slope can cause significant damage to homes. According to the stability study, some mitigation and prevention procedures were suggested in order to allow human occupation of the Lubango’s urban area adjacent to the slopes.

A new species, Chaerilus pseudoconchiformus sp. n., is described from Xizang, China. The present new species is distinguished from its congeners by a body length of 32−40 mm, carapace with the anterior margin straight, chela with length/width ratio average of 3.3 in males (3.2−3.4, two adults), and 2.5 in females (2.3−2.6, nine adults), eight or nine (eight usually) rows of denticles on fixed and movable fingers of pedipalp chelae, five pectinal teeth in males and three or four in females. To date, the chaerilid species fauna of China consists of nine species. An updated identification key to Chaerilus from China is presented.

A new species of pycnogonid collected by the Chinese research vessel, R/V HY IV, during deep sea cruises to the South China Sea in 2013, is described. The new species, Hemichela nanhaiensis, obtained from more than 1300 m depth, is distinguished from the other two species in the genus by the characters of the chela dactylus with 12 denticulations on the inner margin and by the presence of taller tubercles on the lateral processes.

Two experiments were conducted to determine a suitable feeding schedule and the optimal density of Artemia nauplii on the survival and development of mud crab Scylla serrata larvae. The first experiment consisted of 10 treatments, where rotifers were shifted to Artemia nauplii at the zoea (Z) 1, 2, 3, 4 and 5 stages. Five other treatments were similar to these first five; however, rotifers were continuously added together with Artemia nauplii. The second experiment consisted of five treatments that were carried out to determine the optimal Artemia nauplii density. Four treatments fed different Artemia densities (0.5, 1, 1.5, 4 individuals (ind.)/mL) and in the fifth treatment the density of Artemia nauplii was increased with the developing zoeal stage. The survival rate until the Z5 stage was higher when Artemia were supplied from the Z3 stage (P

Austinograea rodriguezensis sp. nov. is the first bythograeid crab to be described from the Indian Ocean. Specimens were collected from 22 km north of the Rodriguez Triple Junction, at 2,420 to 2,450 m depth, during the KR00-05 Indian Ocean Cruise (JAMSTEC) in August 2000. This is the fourth species of the genus Austinograea described and the tenth in the family Bythograeidae. This crab inhabits black smoker complexes (temperature 360°C, pH 3.4) with other vent-associated animals, including Rimicaris shrimps, Bathymodiolus mussels, Alviniconcha snails, unidentified actiniarians, and zoarcid fish. Austinograea rodriguezensis differs remarkably from the other three species of Austinograea in the male gonopod and chela morphology. However, other characters of the species are very similar to Austinograea williamsi. A key to the species of the genus Austinograea is provided.

Hermit crabs collected from submarine caves in the Ryukyu Islands, south-western Japan, were represented by one species of the Diogenidae and six species of the Paguridae, including two new species of Catapaguroides A. Milne-Edwards and Bouvier, 1892. Two new species named Catapaguroides iejimensis and C. kasei are described and illustrated in detail. These taxa appear most closely allied to C. foresti McLaughlin, 2002a, in the shape of carpus and chela of the right cheliped and completely unarmed left chela. However, C. iejimensis is immediately distinguished from C. foresti and C. kasei by having slightly dilated and semisphere-shaped corneas of the ocular peduncles (in the latter two species, reduced and cone-shaped corneas) and two or three spines proximally on the dorsal surface of the palm of the right cheliped (in the latter two species, unarmed on the dorsal surface of the right palm). Catapaguroides kasei closely resembles C. foresti, but differs from the latter in the length of the carpus of the...

A new species of sponge-endosymbiotic shrimps, Periclimenoides tyrannodentatus, is described and illustrated. The species is remarkable for its stout subspatulate first pereiopods chelae with lateral fan-shaped pectination on their dactyli. Due to this character and simple ambulatory dactyli, the new species is similar to the type species of the genus, P. odontodactylus. Another remarkable character is in the unique shape of the minor chela of the second pereiopods; the distal cutting edges of its compressed fingers are distinctly expanded and armed with quite impressive dentitions. An identification key to the three currently recognised species of the genus Periclimenoides is provided. The new species represents the first record of the genus Periclimenoides from Taiwan.

Fiddler crabs Uca uruguayensis were collected monthly in Punta Rasa, at the southern end of the Samborombon Bay, Rio de la Plata, Argentina, from February, 1995, to March, 1996. Throughout the study, 1,115 of 12,033 crabs (9.3%) were infested by different developmental stages of the branchial bopyrid Leidya distorta, which is herein reported for the first time as infesting U. uruguayensis. The distribution of this parasite, previously known from New Jersey to Rio de Janeiro, is now extended even farther south, to the mouth of the Rio de la Plata. Prevalence of L. distorta increased as a function of crab size. The newly settled cryptoniscus larvae were found in the space between contiguous gill lamellae after invading a previously uninfested branchial chamber. The cryptoniscus larva transformed into an early juvenile and, after molting one or more times, migrated to the roof of the branchial chamber, where it grew and finally reached the ovigerous condition. Female parasites usually carried cryptonisci or males, eventually both, on their bodies. Males were found in different positions on the females as the latter developed. Crabs housing a mature female parasite frequently bore an unpigmented area on the lateral wall of the branchial chamber. An additional faded area was sometimes observed on the bottom of the eye orbit. Adult female parasites usually produced a subtle lateral swelling on the carapace of the host, this deformation being more marked in smaller crabs than in larger ones. The major chela of the male crabs parasitized by adult females was, on average, 6.5% shorter than that of unparasitized ones. Alterations of the gills of the host were noticed: the adult female parasite had a strong dorsal carina that fitted between the fourth and fifth gills of the crab, displacing them laterally and making contact with the floor of the branchial chamber. The inner surface of the crab branchiostegite bore a large horizontal vessel from which the parasite presumably obtained hemolymph. Besides the bopyrid isopod forming the subject of this report, we found 61 crabs harboring a nematode larva, identified as Skrjabinoclava sp., among the internal organs of the crab.

During an ongoing systematic revision of the Decapoda Grapsoidea (here defined as including the families Gecarcinidae, Grapsidae s. str., Plagusiidae, Sesarmidae, and Varunidae; see Schubart et al., 2000a), it became evident that adult and larval morphology of two Central American genera, Glyptograpsus and Platychirograpsus, differs greatly from that of all other genera within this superfamily. Several important morphological characters are shared by these two genera and represent synapomorphies when compared to the other grapsoids. Both of these genera lack a pleurobranch on the sixth thoracic segment. Adult males of Glyptograpsus and Platychirograpsus are all strikingly heterochelous with the major chela being conspicuously flattened anteriorly and showing a subproximal articulation with the carpus. The distal portion of the male gonopod is uncinate, with a narrowed, elongate terminus. The anteriormost portion of the sternum consists of a narrow, fused sternite terminated in a distinctly flange...

A new species of varunine crab of the genus Orcovita Ng & Tomascik, 1994, O. mcneiceae sp. nov., is described from the Loyalty Islands. The new species is easily distinguished from congeners by the form of its carapace, chela, ambulatory legs, abdomen and male first pleopod. Une nouvelle espece de crabe Varuninae du genre Orcovita Ng & Tomascik, 1994, O. mcneiceae sp. nov., est decrite des iles Loyautes. La nouvelle espece se distingue aisement de ses congeneres par la forme de sa carapace et par ses chelipedes, pattes ambulatoires, son abdomen et par la premiere patte copulatoire du mâle.

We describe Tanaopsis japonica sp. nov. from intertidal and nearshore habitats around Hokkaido Island, northern Japan. This species closely resembles T. chotkarakde Bird & Bamber, 2000 and T. rawhitia Bird, 2011 in having the uropod with the endopod biarticulate and the exopod uniarticulate, but differs from them in the following characters: pereonite 4 as long as pereonite 5; mandibles lacking the molar; the number of simple setae on the antenna, propodal palm, and dactylus of pereopods 1–3; the number of spiniform setae on the cutting surface of the chelipedal dactylus; and the number of setae on the pleopods. We also determined a nearly complete nucleotide sequence for the 18S rRNA gene in T. japonica. In both sexes, Tanaopsis japonica sp. nov. bears serial ridges and grooves on the chela, antennule, and antenna. Parallel, fringed hatch marks on the chelipedal dactylus may function in stridulation. A series of denticulate ridges on the dorsal surface of antennal article 2 faces the ventral side of article 1 of the antennule, where there is a ventral series of slight grooves. Although the ranges of motion of the antennule and antenna were unclear, the ridges and grooves on the antenna and antennule may also function in producing sound. Two outer series of ridges on the chela, together with an outer furrow on the chela, may function in digging, by allowing bottom-sediments to be efficiently pushed aside.

Uma espécie de picnogonídeo classificada na família Pallenopsidae Fry, 1978 e no gênero Pallenopsis Wilson, 1881 é registrada neste estudo para a costa do estado da Paraíba (nordeste do Brasil), com base na identificação de três espécimes fêmeas coletadas na zona infralitoral em profundidades de 12 a 34 metros. Pallenopsis fluminensis (Krøyer, 1844) é a quarta espécie de Pycnogonida registrada para a região. Até então, apenas Anoplodactylus batangensis (Helfer, 1938), A. eroticus Stock, 1968 e A. mirim Lucena, Araújo & Christoffersen, 2015 haviam sido registradas para a costa da Paraíba. Pallenopsis fluminensis é diagnosticada pelo tronco com setas pequenas na borda distal de cada segmento; probóscide com setas terminais; processos laterais com pequenas setas dorsais; palpos sem setas e reduzidos a um pequeno tubérculo; quela com muitas setas, palma 1.5 vezes mais longa que larga; ovígeros com oito artículos nas fêmeas, sendo os artículos 5 e 6 subiguais, e o 8 pouco menor que o 7; e a tíbia 1 sem uma cobertura densa de setas. Até o momento, P. fluminensis é a única congênere proveniente da costa Atlântica da América do Sul sem uma densa cobertura de setas sobre a tíbia 1.Palavras chave: Arthropoda, Chelicerata, Pantopoda, Atlântico oeste, região tropical, zona costeira.Abstract: A pycnogonid species classified in the family Pallenopsidae Fry, 1978 and the genus Pallenopsis Wilson, 1881 is recorded in this study for the coast of the state of Paraíba in northeastern Brazil based on the identification of three female specimens collected from the infralittoral zone at depths of 12 to 34 meters. Pallenopsis fluminensis (Krøyer, 1844) is the fourth species of Pycnogonida recorded for the region. To date, only Anoplodactylus batangensis (Helfer, 1938), A. eroticus Stock, 1968 and A. mirim Lucena, Araújo & Christoffersen, 2015 have been recorded for the coast of the state of Paraíba. Pallenopsis fluminensis is diagnosed by a trunk with small setae on the distal border of each segment; proboscis with terminal setae; lateral processes with small setae; palps without setae and reduced to a small knob; chela with many setae, palm 1.5 times longer than wide; ovigers with eight articles on females, articles 5 and 6 subequal and article 8 not much smaller than 7; and tibia 1 without dense cover of the setae. To date, P. fluminensis is the only congener from the Atlantic coast of South America without a dense cover of setae on tibia 1.Key words: Arthropoda, Chelicerata, Pantopoda, Western Atlantic, tropical region, coastal zone.

A second species of the pagurid genus Enneophyllus McLaughlin, 1997, E. ecarina n. sp., is described and illustrated on the basis of two specimens collected from the upper bathyal depths off Amami-ohshima Island, Ryukyu Islands, southern Japan. The new species is immediately distinguished from the sole known congener, E. spinirostris McLaughlin, 1997, from the Banda Sea, Indonesia, by the non-operculiform right chela and fewer ventral spiniform setae of the ambulatory dactyli. The type species of Enneophillus, E. spinirostris, was represented only by the male holotype, and examination of the female paratype of this new species enables documentation of female characteristics in the generic diagnosis. Like E. spinirostris, the new species inhabits scaphopod shells.

Macrobrachium jelskii is a freshwater shrimp endemic to South America, occurring in all major Brazilian basins. It is used in various activities, such as fishing, fishkeeping and even as food for humans and animals, and therefore its distribution is affected by anthropic influence. Misidentification of M. jelskii is recurrent because of its morphological similarity to some sympatric species such as M. amazonicum and M. acanthurus. Thus, the aim of this study is to redescribe M. jelskii, proposing some characteristics that allow for a clearer differentiation of this species when compared to other similar congeneric species that occur in South America. The informative characters were the size and the shape of the rostrum, the ratio of the carpus and chela, the ratio of the chela and carapace length and the shape of the carpus of the second pereiopod, as well as the ratio between the length of the internal pair of posterior spine of telson and median apex of the posterior margin of telson. Although the intraspecific variability is high, the combination of the characters mentioned herein, including a morphological key, is very useful and makes it easier to differentiate between these three species.

Three species of the genus Automate De Man, 1888 are described herein, including two new species: A. anacanthopusoides sp. nov. and A. spinosa sp. nov.. Automate anacanthopusoides sp. nov. can be easily identified by the presence of a rostrum, the notch on the lower margin of the major chela, the stout minor cheliped and the cutting edge of the pollex not dentate, and by the absence of spines on the ventral margin of the propodus of the third and fourth pereiopod. Automate spinosa sp. nov. can be easily identified by the nearly straight anterior margin of the carapace, and the presence of spines on the ventral margin of the propodus of third and fourth pereiopod. A key of all species of the Automate is provided.

Scorpio Linnaeus, 1758 (family Scorpionidae Latreille, 1802) was considered monotypic for over a century, and comprised a single species, Scorpio maurus Linnaeus, 1758, with 19 subspecies, distributed from West Africa, throughout the Maghreb and the Middle East, to Iran. Two parapatric subspecies, Scorpio maurus fuscus (Ehrenberg, 1829) and Scorpio maurus palmatus (Ehrenberg, 1828), have long been recognized in the eastern Mediterranean region. We examined morphological variation, burrow architecture and genetic divergence among 39 populations across the distribution of the two subspecies to assess whether they are conspecific and, if not, how many species might be involved. Cuticle coloration, pedipalp chela digital carina condition, and selected measurements were recorded. Sixty burrows were excavated and examined for burrow structure and depth. A multilocus dataset comprising concatenated fragments of one nuclear (28S rDNA) and three mitochondrial (12S rDNA, 16S rDNA, Cytochrome c Oxidase Subunit I) loci, totaling ca. 2400 base-pairs, was produced for 41 individuals, and a single-locus dataset comprising 658 base-pairs of the COI locus for 156 individuals. Despite overlapping ranges in morphometric characters of pedipalp chela shape, the putative subspecies were easily distinguished by cuticle coloration and condition of the pedipalp chela digital carina, and were also found to differ significantly in burrow architecture and depth. Phylogeographical analyses of the COI and multilocus datasets recovered seven distinct clades. Separate analyses of mitochondrial sequences, and combined analyses of mitochondrial and nuclear sequences support most clades. The two major clades corresponded with the geographical distributions of S. m. fuscus and S. m. palmatus in the region. Specimens from these clades were genetically distinct, and exhibited different burrow structure in geographically-proximate localities, suggesting reproductive isolation. The palmatus clade included two distinct subclades of specimens from localities adjacent to the Dead Sea. Three other clades, comprising specimens from the most northeastern localities, were tentatively assigned to subspecies previously recorded in neighboring Jordan and Syria. The morphological, behavioral and genetic evidence supports previous suggestions that Scorpio maurus is a species complex and justifies the following taxonomic emendations: Scorpio fuscus (Ehrenberg, 1829), stat. nov.; Scorpio kruglovi Birula, 1910, stat. nov.; Scorpio palmatus (Ehrenberg, 1828), stat. nov.; Scorpio propinquus (Simon, 1872), stat. nov.

Paratanais rosadi sp. n. described from Puerto Rican coastal waters represents the first species of the genus from the northwestern Atlantic. It is distinguished from the other Paratanais species by a combination of characters, including article-2 of the maxilliped palp with a geniculate, finely-serrulate seta on inner margin; chela with stiff, geniculate, seta arising from propodus between fixed finger and dactylus and with short, stout, finely serrulate, seta on inner distal face of propodus adjacent to base of dactylus; carpus of pereopods 4−6three, instead of four stout modified spiniform setae distally, uropodal exopod distinctly shorter than endopodal article-1; and uropodal endopod with articles of about of equal in length. A key for the separation of Paratanais species from the Atlantic Ocean is presented.

By examining the morphological basis of force generation in the chelae (claws) of both molluscivorous and non-molluscivorous crabs, it is possible to understand better the difference between general crab claw design and the morphology associated with durophagy. This comparative study investigates the morphology underlying claw force production and intraspecific claw dimorphism in six brachyuran crabs: Callinectes sapidus (Portunidae), Libinia emarginata (Majidae), Ocypode quadrata (Ocypodidae), Menippe mercenaria (Xanthidae), Panopeus herbstii (Xanthidae), and P. obesus (Xanthidae). The crushers of the three molluscivorous xanthids consistently proved to be morphologically ‘strong,’ having largest mechanical advantages (MAs), mean angles of pinnation (MAPs), and physiological cross-sectional areas (PCSAs). However, some patterns of variation (e.g. low MA in C. sapidus, indistinguishable force generation potential in the xanthids) suggested that a quantitative assessment of occlusion and dentition is needed to understand fully the relationship between force generation and diet. Interspecific differences in force generation potential seemed mainly to be a function of differences in chela closer muscle cross-sectional area, due to a sixfold variation in apodeme area. Intraspecific dimorphism was generally defined by tall crushers with long in-levers, though O. quadrata exhibited an extreme dimorphism suggesting that factors unrelated to a speed–strength dichotomy (e.g. sexual selection) have shaped dimorphism of that species. It is concluded here that: (1) the majority of interspecific claw strength variation is a function of closer muscle cross-sectional area; (2) variation in claw morphology related to force production and transmission does have some relation to hardness of diet; (3) claw dimorphism in many species does seem to be related to strength and speed trade-offs; (4) factors besides molluscivory must be considered to understand claw evolution fully; (5) a quantitative assessment of force distribution, lacking in the literature, is essential for a more complete understanding of the relationship between claw design and ecological function.

Typically ≥90% of the eggs in clutches fertilized by hardshell Prince William Sound Lithodes aequispinus males ≥107 mm carapace length initiated division. Golden king crab males with only one chela and those with post-molt carapaces ≥11 days old were effective parents. Some test males had exclusive access to three ripe females. Their first and second mates all produced viable clutches with 81–100% of eggs exhibiting development. Not all males induced a third female to ovulate. The percentage of eggs initiating division in the clutches of their third potential female mates ranged from 56 to 100%.

Some morphometric relationships and biometric aspects were studied in the hermit crab Loxopagurus loxochelis (Moreira, 1901) with the purpose of describing its relative growth and finding the size where sexual maturity is reached. Specimens were collected monthly from September 1995 to August 1997 in the Ubatuba region using double-rig trawl nets. A total of 1084 specimens (625 males and 459 females) was analysed. In this species, sexual dimorphism is particularly evident in chela dimensions. Differences between males and females were found in the left propodus length versus cephalothoracic shield length (CSL) and wet weight (WW) versus CSL relationships. Males showed a high positive allometry in chela growth, while females were close to isometry/negative allometry. The size at which a clear differentiation occurred in the growth of the propodus length and in the increase in weight of males and females was between 4.5 and 6.0mm CSL, suggesting that size at which sexual maturity is reached.

Two shelter substrates (fibre-cement sheets and PVC pipes) and two foodsupply frequencies (once and twice daily) were tested on white-clawed juvenilecrayfish in two separate experiments performed under laboratory conditions.Juvenile crayfish were maintained at an initial density of 50 animals persquaremetre in a flow-through system and fed on fresh Daphniapulex and a feed formulated for rainbow trout. After 120 days,highersurvival (50.5%), but lower growth, was obtained when fibre-cement sheets wereprovided as shelter. A comparison between food supply frequencies showed abetter survival rate (60.5%) when food was provided twice per day althoughtherewere no differences in growth after 80 days of trial. The number of animalswith chela autotomy is positively correlated (r between 0.33 and 0.48 depending ontreatments) with decreases in survival rate. The combination of adequate shelterand frequency of food supply could reduce the agonistic behaviour of juvenilecrayfish.

[Some morphological relationships are investigated amongst three populations of Potamonautes warreni (Calman, 1918) and the species is redescribed. Differences between sexes as well as the growth of the carapace, chelipeds, and handedness are quantified. Sex ratios did not differ significantly from 1 : 1 among sites, and no differences in the carapace variables were evident between sexes. Both sexes were heterochelous, with the right chela usually being larger in males than in females. Sexual dimorphism is evident for the width of the abdominal somites. The functional significance of an enlarged right chela, and that of patterns of allometric growth are discussed. In addition, the structure of pleopod 1, mandibular palp, chelipeds, and the third maxilliped are described and illustrated. The distribution of P.warreni is re-examined and the species appears to be restricted to the Orange River System and its major tributaries such as the Vaal River in South Africa and Namibia. Quelques relations morphologiques ont ete etudiees chez trois populations de Potamonautes warreni (Calman, 1918) et l'espece est redecrite. Des differences entre les sexes ainsi que la croissance de la carapace et des chelipedes, la proportion de droitiers et gauchers, ont ete quantifies. Les sex ratios n'ont pas differe significativement de 1 : 1 sur les differents sites et aucune difference dans les variables de la carapace n'est evidente entre les sexes. Les deux sexes sont heterocheles, avec la pince droite habituellement beaucoup plus grande chez les mâles que chez les femelles. Le dimorphisme sexuel est evident sur la largeur des somites abdominaux. La signification fonctionnelle d'une pince droite agrandie et celle des modeles de croissance allometrique sont discutees. De plus, la structure du pleopode 1, du palpe mandibulaire, des chelipedes et les troisiemes maxillipedes sont decrits et illustres. La distribution de P.warreni est reexaminee et l'espece apparait comme limitee au systeme de la riviere Orange et de ses principaux tributaires comme la riviere Vaal en Afrique du Sud et Namibie., Some morphological relationships are investigated amongst three populations of Potamonautes warreni (Calman, 1918) and the species is redescribed. Differences between sexes as well as the growth of the carapace, chelipeds, and handedness are quantified. Sex ratios did not differ significantly from 1 : 1 among sites, and no differences in the carapace variables were evident between sexes. Both sexes were heterochelous, with the right chela usually being larger in males than in females. Sexual dimorphism is evident for the width of the abdominal somites. The functional significance of an enlarged right chela, and that of patterns of allometric growth are discussed. In addition, the structure of pleopod 1, mandibular palp, chelipeds, and the third maxilliped are described and illustrated. The distribution of P.warreni is re-examined and the species appears to be restricted to the Orange River System and its major tributaries such as the Vaal River in South Africa and Namibia. Quelques relations morphologiques ont ete etudiees chez trois populations de Potamonautes warreni (Calman, 1918) et l'espece est redecrite. Des differences entre les sexes ainsi que la croissance de la carapace et des chelipedes, la proportion de droitiers et gauchers, ont ete quantifies. Les sex ratios n'ont pas differe significativement de 1 : 1 sur les differents sites et aucune difference dans les variables de la carapace n'est evidente entre les sexes. Les deux sexes sont heterocheles, avec la pince droite habituellement beaucoup plus grande chez les mâles que chez les femelles. Le dimorphisme sexuel est evident sur la largeur des somites abdominaux. La signification fonctionnelle d'une pince droite agrandie et celle des modeles de croissance allometrique sont discutees. De plus, la structure du pleopode 1, du palpe mandibulaire, des chelipedes et les troisiemes maxillipedes sont decrits et illustres. La distribution de P.warreni est reexaminee et l'espece apparait comme limitee au systeme de la riviere Orange et de ses principaux tributaires comme la riviere Vaal en Afrique du Sud et Namibie.]

An identity is questioned only when it is menaced, as when the mighty begin to fall, or when the wretched begin to rise, or when the stranger enters the gates, never, thereafter, to be a stranger: the stranger's presence making you the stranger, less to the stranger than to yourself. Identity would seem to be the garment with which one covers the nakedness of the self; in which case, it is best that the garment be loose, a little like the robes of the dessert, through which robes one's nakedness can always be felt, and sometimes, discerned. This trust in one's nakedness is all that gives one the power to

The scanning electron microscope was used to study the changing features of scorpion embryos from the blastula through early stages in the development of appendages. The earliest scorpion fossils (Silurian period) have structures more advanced than the embryos herein, so the possibility is considered that these embryos still retain and display some features indicative of evolutionary patterns in adult pre-Silurian ancestors. The blastodisc stage is followed by a knob-like germinal center that gives rise to most of the embryo body. The germinal center elongates on the ventral surface of the spherical yolk mass. The broad cephalic lobe is first delineated from the following pedipalpal segment. The limbbuds for the pedipalps and anterior walking legs appear, as additional segments are added at a growth zone at the rear of the embryo body. Initially, in the cephalic lobe there are no limbbuds; then the cheliceral buds emerge from the posterior part of the lobe. The stomodeum appears first in the anterior half of the cephalic lobe, but an oral groove forms and the mouth is displaced posteriorly within the groove. This repositioning allows space anteriorly for invagination (semilunar grooves) of epithelium for the brain and medial eyes. The mouth is directed ventrally in all stages of this study. The widespread chelicerae are initially posterior to the mouth, but later move anterior and dorsal to it. Small limbbud bulges on mesosomal segments disappear later and never become protruding appendages. Metasomal segments are produced free from the yolk surface in a ventral flexure beneath the embryo body. The telson starts as two spherical lobes, but later elongates and tapers distally, not yet developing the sharp sting (aculeus) seen in Silurian and all subsequent scorpions. The walking legs are digitigrade, as in most fossil aquatic scorpions. Segments are delineated in the appendages; the chelicerae and pedipalps are divided distally for chela (claw) formation. Bilateral swellings (limbbuds) on the third abdominal segment become larger than the others, indicating the site of pectine formation. The early fin-like pectines are somewhat posterior in the mesosoma, suggesting ancestral swimming, maneuvering, and balancing for the elongate abdomen. The pectinal surface is initially smooth but later transverse striations increase the surface area as a possible respiratory adaptation. Pectinal teeth (present in Silurian and all subsequent scorpions) and foward movement and merging of anterior abdominal segments are not yet evident in embryos of this study. J. Morphol. 250:70–88, 2001. © 2001 Wiley-Liss, Inc.

Animals in competitive interactions often assess the competitive ability of opponents using signals. Signals used in competitive interactions are generally predicted to be honest, but open to low levels of deceit. Such ‘‘incomplete honesty’’ in signals can be studied by using signal residuals, the residuals from the regression of a measure of signal structure on competitive ability. Specifically, individuals with positive signal residuals produce signals that exaggerate their competitive ability; deceptive use of these signals may occur if signalers for whom the signal exaggerates their apparent competitive ability use the signal more frequently. I used this framework to examine the use of the open chela display by big-clawed snapping shrimp (Alpheus heterochaelis). Competitive interactions between snapping shrimp are resolved primarily on the basis of body size, and the open chela display is used by males to assess body size. I found that the production of the open chela display by males responding to superior competitors depends on chela residuals, such that individuals for whom the display exaggerates their apparent size produce the display more often. This effect can be seen both in response to isolated chelae and in staged competitive interactions. Interactions involving shrimp with larger chela residuals are long and highly escalated, suggesting that chela residuals affect assessment of competitive ability. Thus, the increased use of the open chela display by males for which the display exaggerates apparent body size is an example of deceptive use of an otherwise honest signal. Key words: Alpheus heterochaelis, deception, honesty, reliability, signals, snapping shrimp. [Behav Ecol 11:614–623 (2000)]

The mesomorphic 4,4-bis[4-n-octyloxybenzoyloxy]azobenzene dinuclear chloro-bridged cycloplatinated complex [(Azo)Pt(mu;-Cl)]2 (smectic C between 263 and 342 C) has been reacted with different chela...

The structure, growth, differentiation and function of crustacean chelipeds are reviewed. In many decapod crustaceans growth of chelae is isometric with allometry level reaching unity till the puberty moult. Afterwards the same trend continues in females, while in males there is a marked spurt in the level of allometry accompanied by a sudden increase in the relative size of chelae. Subsequently they are differentiated morphologically into crusher and cutter making them heterochelous and sexually dimorphic. Of the two, the major chela is used during agonistic encounters while the minor is used for prey capture and grooming. Various biotic and abiotic factors exert a negative effect on cheliped growth. The dimorphic growth pattern of chelae can be adversely affected by factors such as parasitic infection and substrate conditions. Display patterns of chelipeds have an important role in agonistic and aggressive interactions. Of the five pairs of pereiopods, the chelae are versatile organs of offence and defence which also make them the most vulnerable for autotomy. Regeneration of the autotomized chelipeds imposes an additional energy demand called "regeneration load" on the incumbent, altering energy allocation for somatic and/or reproductive processes. Partial withdrawal of chelae leading to incomplete exuviation is reported for the first time in the laboratory and field in Macrobrachium species.