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We present a new formulation of the V-formation problem for migrating birds in terms of model predictive control (MPC). In our approach, to drive a collection of birds towards a desired formation, an optimal velocity adjustment (acceleration) is performed at each time-step on each bird's current velocity using a model-based prediction window of $T$ time-steps. We present both centralized and distributed versions of this approach. The optimization criteria we consider are based on fitness metrics of candidate accelerations that birds in a V-formations are known to benefit from, including velocity matching, clear view, and upwash benefit. We validate our MPC-based approach by showing that for a significant majority of simulation runs, the flock succeeds in forming the desired formation. Our results help to better understand the emergent behavior of formation flight, and provide a control strategy for flocks of autonomous aerial vehicles.

Streptocephalus sirindhornae Sanoamuang, Murugan, Weekers, and Dumont, 2000 (Figs 1 and 2) Streptocephalus sirindhornae Sanoamuang, Murugan, Weekers, and Dumont, 2000; Sanoamuang et al., 2007; Dararat et al., 2012; Sornsupharp et al., 2013; Rogers et al., 2013; Rogers and Padhye, 2014. Material examined. China: Yunnan, Luxi County: Laogantang temporary pond, 24 36 ' 07.05" N, 103 42 ' 33.88 " E, 5 males, 6 females, total body length 23.1 to 30.8 mm, September 2008, S.S. Shu legit. Chongzuo City, Guangxi Zhuang Autonomous Region: Ecology Park, swamp for white-headed langur, 22 16 ' 22.13 " N, 107 30 ' 54.87 " E, 7 males, 6 females, total body length 20.4 to 23.3 mm, August 2009, M. Hou legit. Thailand: Maha Sarakham: aquaculture pond, 16 �� 15 ��� 56.50 ������ N, 103 ��08��� 27.65 ������ E, 10 males, 8 females, August 2012, S.S. Shu legit. Diagnosis. Male. Frontal appendage simple and short. First antenna filiform, second antenna well developed (Fig. 1 B). Distal antennomere with distinct basomedial outgrowth (wart) (Fig. 1 C). Proximal antennomere with stout distomedial outgrowth, consisting of a cylindrical, robust, bigeniculated peduncle of the long type (sensu Maeda- Martinez et al. 1995), terminating in a scleroid cheliform structure (hand) (Fig. 1 B); peduncle without pulvinus, with three to five dorsobasal fleshy processes with their ventral surfaces bearing longitudinal rows of papillae (Fig. 1 B); peduncle inflexion lateral side with longitudinal row of 9 to 14 slender conical processes (Fig. 1 B, C); medial side with longitudinal row of triangular protuberances (Fig. 1 C). Posterior ramus (so called ���finger in Maeda-Martinez et al. 1995) biramous and longer than anterior ramus (so called thumb in Maeda-Martinez et al. 1995); posterior ramus with a dorsolateral (lower) sickle-shaped subramus, that is curved dorsally, sharply keeled over most of length, with apical third bearing an undulating free margin; posterior ramus with medial (upper) subramus with small rounded protuberances along dorsal margin, with two apical additional subramium equal in length bearing few small rounded protuberances (Fig. 1 B; Fig. 2 A, B, C); spur of thumb broad basally, apically subacuminate (Fig. 2 E, F). Genitalia with lateral linguiform outgrowths, and tubular gonopods ventrally projected with a spinulated medial appendix (Fig. 1 D), basal parts not rigid, non-retractile. Cercopods setose. Female. Ovaries uniramous; brood pouch elongate and fusiform; eggs spherical, ornamented by ribs forming polygonal areas (Fig. 1 E). Cercopods setose. Distribution. Streptocephalus sirindhornae is reported from Thailand (Sanoamuang et al., 2000), southern Laos, and central Cambodia (Rogers et al., 2013), and now China (this study) (Fig. 1 A). Streptocephalus sirindhornae occurs in Yunnan, Luxi County, at an altitude of 1,791 ma.s.l; at the time of the field collection in this site water was turbid, temperature 22.8 ��C, pH 8.3, and dissolved oxygen 5.5 mg /L. The species also occurs in the Guangxi Zhuang Autonomous Region in an Ecology Park at 169 ma.s.l. The materials from these two locations represent the first records of the family, genus and species in China, and document their northern and easternmost distributional range in South East Asia. Comments.The Chinese Streptocephalus material corresponds to the description of S. sirindhornae, in having the main diagnostic characters described by Sanoamuang et al. (2000): (1) second antenna proximal antennomere (���basal joint) with a basal projection (���wart) (Fig. 2 C); (2) the form of the antennal appendage (peduncle and���hand); the form of the gonopods (Fig. 2 B); and (3) egg morphology (Fig. 2 E). Conversely, the total body length of the specimens from China (23.1 to 30.8 mm of Yunnan specimens, and 20.4 to 23.3 mm of Guangxi specimens), is longer than those from the type locality (14.2 to 17.7 mm) (Sanoamuang et al., 2000). The variation range of the number of slender conical processes located at the lateral side of the antennal peduncle inflexion (Fig. 1 B) were originally reported as from 10 to 12 (Sanoamuang et al., 2000), whereas in our material they were from 9 to 10 in material from Yunnan, and 12 to 14 in material from Guangxi (Fig. 1 B). The original description reported the distal antennomere (slender processes) on both sides of the peduncle inflexion (Sanoamuang et al., 2000), however the specimens we examined from Thailand and China had these processes on the lateral side only. The triangular protuberances located at the medial side of the antennal peduncle (Fig. 1 C) are present in all specimens from Thailand and China. Their number and size are variable among individuals, even in the same population. Such triangular protuberances were not mentioned in the original description of the species. As in Streptocephalus dichotomus Baird, 1860, we confirm that the basal lateral side of the thumb in S. sirindhornae has a well developed hollow (Sanoamuang et al., 2000) (Fig. 1 B). The fingers of S. dichotomus and S. sirindhornae were shown by Sanoamuang et al. (2000) with a depression on the ventral margin near to the confluence of the two rami. This depression is deeper in the material from Thailand, than in material from Yunnan and Guangxi (Fig. 2 G-I). The two apical subrami of posterior ramus is unequal in the material from Thailand and Guangxi but subequal from Yunnan (Fig. 2 A-C).The spur of the anterior ramus was described as broadly knife shaped, not constricted apically (Sanoamuang et al., 2000); the spur in specimens from Thailand and Yunnan fits the original description (Fig. 2 D, E), however the Guangxi specimens bear a triangular spur (Fig. 2 F). Phenotypic plasticity in inter- and intra-populations is an important adaptation in response to variable environments and predators (Cohen, 2012). Based on the morphological differences, the populations of S. sirindhornae from Maha Sarakham in Thailand, and Yunnan and Guangxi in China show phenotypic plasticity possibly related to environmental differences. The new records extend the known distribution range of S. sirindhornae in altitude (up to 1791 ma.s.l.), and in eastern and northern latitudes, from tropical Thailand, Laos, and Cambodia to temperate zones in China. The fairy shrimp S. sirindhornae contains high levels of protein (Dararat et al., 2012), and is widely cultured commercially in aquaculture farms as live food for freshwater ornamental fish and prawns (Sornsupharp et al., 2013).The species was imported to China in 2011 in Xiamen City, Fujian Province as an ornamental pet named the ���Queen Fairy Shrimp(http://konglongxia.ywbb.com). The morphological variation of the Chinese populations here reported may help researchers to distinguish between natural and introduced forms. FIGURE. 2. Details of the second antenna of Streptocephalus sirindhornae. A, D, G, male from Maha Sarakham, Thailand. B, E, H, male from Yunnan, China. C, F, I, male from Guangxi, China. A, B, C, distal part of medial (upper) subramus of the posterior ramus showing rounded protuberances and the two apical subrami unequal in length. D, E, F, lateral view of the spur of thumb. G, H, I, lateral view of the right posterior ramus showing the depression on the ventral margin near to the confluence of the two rami., Published as part of Shu, Shusen, Maeda-Martinez, Alejandro M., Rogers, D. Christopher, Yang, Junxing & Chen, Xiaoyong, 2015, Morphological characterization of Streptocephalus sirindhornae (Branchiopoda: Anostraca) from South East Asia: First record of the Streptocephalidae from China, pp. 447-450 in Zootaxa 3911 (3) on pages 447-449, DOI: 10.11646/zootaxa.3911.3.11, http://zenodo.org/record/236184, {"references":["Sanoamuang, L., Murugan, G., Weekers, P. H. & Dumont, H. J. (2000) Streptocephalus sirindornae, new species of freshwater fairy shrimp (Anostraca) from Thailand. Journal of Crustacean Biology, 20, 559 - 565. http: // dx. doi. org / 10.1163 / 20021975 - 99990073","Sanoamuang, L., Sanoamuang, N., Saengphan, N., Chusing, R., Athibai, S. & Lekchan, S. (2007) Species diversity and distribution of fairy shrimps in Thailand. KhonKaen University, KhonKaen, 19 pp.","Dararat, W., Lomthaisong, K. & Sanoamuang, L. (2012) Biochemical composition of three species of fairy shrimps (Branchiopoda: Anostraca) from Thailand. Journal of Crustacean Biology, 32, 81 - 87. http: // dx. doi. org / 10.1163 / 193724011 X 615352","Sornsupharp, S., Dahms, H. U. & Sanoamuang, L. (2013) Nutrient composition of fairy shrimp Streptocephalus sirindhornae nauplii as live food and growth performance of giant freshwater prawn postlarvae. Aquaculture Nutrition, 19, 349 - 359.","Rogers, D. C., Thaimuangphol, W., Saengphan, N. & Sanoamuang, L. (2013) Current knowledge of the South East Asian large branchiopod Crustacea (Anostraca, Notostraca, Laevicaudata, Spinicaudata, Cyclestherida). Journal of Limnology, 72 (S 2), 69 - 80. http: // dx. doi. org / 10.4081 / jlimnol. 2013. s 2. e 5","Rogers, D. C. & Padhye, S. (2014) A new species of Streptocephalus (Crustacea: Anostraca: Streptocephalidae) from the Western Ghats, India, with a key to the Asian species. Zootaxa, 3802 (1), 075 - 084. http: // dx. doi. org / 10.11646 / zootaxa. 3802.1.6","Cohen, R. G. (2012) Morphological diversity displayed by high altitude Branchinecta papillata (Anostraca) and additional morphological comparisons with Branchinecta achalensis. Journal of Crustacean Biology, 32, 1 - 13. http: // dx. doi. org / 10.1163 / 193724011 X 617404"]}

Shu, Shusen, Maeda-Martinez, Alejandro M., Rogers, D. Christopher, Yang, Junxing, Chen, Xiaoyong (2015): Morphological characterization of Streptocephalus sirindhornae (Branchiopoda: Anostraca) from South East Asia: First record of the Streptocephalidae from China. Zootaxa 3911 (3): 447-450, DOI: http://dx.doi.org/10.11646/zootaxa.3911.3.11

Stenorynchoacrum new genus Type species: Stenorynchoacrum xijiangensis new species Diagnosis. Stenorynchoacrum can be distinguished from existing genera of Labeoninae by the following characters. Middle part of rostral cap undeveloped, narrow, only covering the base of the upper jaw, both sides of rostral cap well developed and extending upward, rostral cap connected the lower lip, both lateral part of which free, as the result of a long postlabial groove separating the posterior margin of lateral part of lower lip and the isthmus, the median part of lower lip protrudes to form a round fleshy pad, whose posterior margin continuous with the mental region, no crescentic fold surrounding the fleshy pad (Fig. 2). The genus possesses some additional characters: the ventral margin of rostral cap unfringed, upper lip regresses to form a row of thin, tiny lobes adnated to upper jaw, the posterior margin of lower jaw connected the anterior part of lower lip, lower lip well developed, variable papillae scattered on rostral cap and lower lip, the anterior margin of upper and lower jaws born flexible, cornified sheath, two pairs of barbels, three rows of pharyngeal teeth, and eight branched dorsal-fin rays. Etymology. Sten from stenos Greek, means narrow; ryncho from rhynchos, Greek, means snout; acr, Greek, means the extremities of the body (snout, ears or trotters), so rynchoacrum means ventral margin of rostral cap. Stenorynchoacrum alludes to the narrow and undeveloped rostral cap of this genus., Published as part of Huang, Yanfei, Yang, Junxing & Chen, Xiaoyong, 2014, Stenorynchoacrum xijiangensis, a new genus and a new species of Labeoninae fish from Guangxi, China (Teleostei: Cyprinidae), pp. 379-386 in Zootaxa 3793 (3) on page 381, DOI: 10.11646/zootaxa.3793.3.6, http://zenodo.org/record/231574

Wang, Dan, Zhao, Yahui, Yang, Junxing, Zhang, Chunguang (2014): A new cavefish species from Southwest China, Sinocyclocheilus gracilicaudatus sp. nov. (Teleostei: Cypriniformes: Cyprinidae). Zootaxa 3768 (5): 583-590, DOI: http://dx.doi.org/10.11646/zootaxa.3768.5.5

Huang, Yanfei, Yang, Junxing, Chen, Xiaoyong (2014): Stenorynchoacrum xijiangensis, a new genus and a new species of Labeoninae fish from Guangxi, China (Teleostei: Cyprinidae). Zootaxa 3793 (3): 379-386, DOI: http://dx.doi.org/10.11646/zootaxa.3793.3.6

Stenorynchoacrum xijiangensis, new species (Table 1, Figures 2–4 a) Holotype. KIZ 2001060488, 78.3 mm SL, Xiangsi Jiang, a tributary of Li Jiang draining to Xi Jiang of Zhu Jiang (Pearl River drainage), Dabu Village, Guilin City, Guangxi Province, China, collected by J. H. Lan on June, 2001 (Fig. 1). Paratypes: KIZ 2001060482−2001060487, 2001060490 − 2001060494, 11 specimens, 45.1-83.3 mm SL, same data as the holotype. Diagnosis. See generic diagnosis. Description. Morphometric data for 12 type specimens are given in Table 1. Body elongate and compressed. Dorsal profile of body convex from tip of snout to dorsal-fin origin with the greatest depth, straight from there to caudal-fin base. The ventral profile of body convex from tip of snout to pelvic-fin origin, straight from anal-fin origin to caudal-fin base. Snout rounded and blunt. Snout length almost equal to postorbital length. Mouth gape arched and narrow, its width accounting for 14.1%−22.7% corresponding head length. Nostrils closer to anterior margin of eye than to snout tip. The ventral margin of rostral cap unfringed, completely covering upper lip and the base of upper jaw. Rostral cap connected to lower lip at the corner of mouth. A depression behind rostral barbel base, extending obliquely upward to lateral extremity of snout cap but not meeting with the sublachrymal groove. The lachrymal groove below rostral barbel base extending obliquely down to the corner of mouth and continuous with postlabial groove. The deep postlabial grooves whose length is about 1 / 3 of corresponding mouth width, divide lower lip into three parts including median portion and two lateral portions. Lateral portions of lower lip free. The median part of lower lip protrudes to form a round fleshy pad, the posterior of which continuous with the mental region. Rostral cap and lower lip covered by regularly arranging, variable fleshy papillae. Among them, two or three rows of papillae at the most-anterior of round fleshy pad smallest, those middle rows of papillae largest. Papillae on the middle part of rostral cap smaller than those on the sides. Eyes large, dorsolaterally situated in the middle of head, visible from ventral view. Interorbital space wide and flat. Two pairs of barbels, rostral barbels longer than maxillary barbels but shorter than eye diameter, maxillary barbels close to corners of mouth. Dorsal fin with three simple and 8 branched rays, emarginate; the last unbranched dorsal-fin ray soft and smooth; dorsal-fin origin at midpoint of snout tip and caudal-fin base, and located vertically in front of pelvic-fin origin. Pectoral-fin with one simple and 14 (7) or 15 (5) branched rays, lightly falcate, shorter than head length; tip of depressed pectoral-fin rays extending along 72 %− 98 % of the distance from pectoral-fin origin to pelvic-fin origin. Pelvic-fin with one simple and 8 (12) branched rays, straight, closer to caudal-fin base than to snout tip and closer to anal-fin origin than to pectoral-fin origin; tip of depressed pelvic-fin rays nearly or already reaching anus, its length shorter than head length. Anal-fin with three simple and five branched rays, straight, closer to caudal-fin base than to pelvic-fin origin. Caudal-fin deeply forked, upper and lower lobes almost equal in length and symmetrical in shape, length of the longest ray 1.7−2.4 times length of the shortest median ray. Lateral line complete and horizontal. Lateral line scales 39 (11) or 38 (1); scale rows above lateral line 6 (12); scale rows below lateral line 4 (12). Predorsal scales irregularly arranged, embedded in small-sized specimens. Scales of abdomen from thorax to base of pectoral-fin small and embedded under skin. Axillary scales at the base of pelvic-fin, scale vagina at dorsal-fin and anal-fin. Circumpeduncle scales 16 (12). Anus located immediately in front of anal-fin origin. Vertebrae 35 (1), 36 (3), 37 (2). Swimbladder with two chambers: anterior one oval, posterior one elongated, 1.5−2.0 times as long as the anterior one. Gill rakers on first gill arch 8 (1) or 10 (2). Pharyngeal teeth 3 rows, 5, 4, 2−2, 4 and 5. Digestive tract long and coiled, the length is 7.5−8.7 (3) times standard length. Color pattern in formalin. Preserved in formalin, body gray and yellowish dorsally and laterally, slightly pale ventrally. All fins gray. No stripe or blotches along dorsal and sides of body. Distribution. Stenorynchoacrum xijiangensis is only known from Xiangsi Jiang, which is a tributary of Li Jiang draining to Xi Jiang of Zhu Jiang Drainage (Pearl River Drainage) in Dabu Village, the south of Guilin City, Guangxi Province, China. Ecology. The species lives in underground caves connected to the surface river in the Karst area. Fish stay in the underground caves in the dry season and swim upward into the rivers during the flood season. Etymology. It alludes Xi Jiang, the drainage of the type locality.

Sinocyclocheilus gracilicaudatus Zhao and Zhang, sp. nov. Figure 1 Holotype: ASIZB 186399, 94.7mm standard length (SL), Zhujiang (Pearl) River Basin, Donglei Cave, Mulun town, Huanjiang County, Guangxi Zhuang Autonomous Region, China; 2009; collected by M. Y. Tian Paratype: ASIZB 186400, 79.0mm SL, ASIZB 186401 (preserved in collection of South China Agricultural University) 60.8mm SL, same data as for holotype. Diagnosis. The new species can be distinguished from other known congeners by the following combination of characteristics: body normal shape; eyes present, normal; well scaled excluding head; lateral-line curved, scales 59���64; half-hard dorsal-fin spine; 8 gill rakers; 8 predorsal vertebrae; caudal peduncle length 21.3���22.7 % of SL; caudal peduncle depth 10.5 ���12.0% SL. Description. General body characters are shown in Figure 1. Meristic features and proportional measurements as percentages of standard length are listed in Table 1. Body moderately elongate and compressed. Dorsal profile convex from snout to dorsal fin, greatest body depth at dorsal fin insertion, and being slightly concave from end of dorsal-fin base to caudal fin. Ventral profile concave, tapering gradually toward anal fin. Head compressed. Two pairs of nostrils, anterior and posterior nostrils neighbored, front edge of anterior nostril midway from snout tip to front edge of eye; anterior-nostril possessing a rim with a fleshy flap forming a small tube. Mouth curved and slightly sub-inferior. Two pairs of barbels; insertion of maxillary barbel in front of anterior nostril, barbel long, extending to middle part of operculum; rictal barbel long, reaching posterior margin of operculum. Eye present and well developed, round, anterior and posterior edge of orbit at one third and half distance between snout tip to posterior margin of operculum, respectively. Cranial sensory canals developed, superaorbital and infraorbital canals connected. Gill opening large. Gill rakers triangular, well developed, 8 on first gill arch, 2 and 6 on epibranchial and ceratobranchial respectively. Pharyngeal teeth in three rows with counts of 1,3,4-4,3,1 (one specimens checked), pharyngeal teeth at outer row strong and well developed, with curved and pointed tip. Pectoral-fin insertion under posterior margin of operculum, pectoral fin not reaching pelvic fin insertion. Pelvic-fin insertion opposite dorsal-fin insertion; pelvic fin long, reaching four fifths of distance from pelvic-fin insertion to anus. Dorsal-fin a little closer to caudal fin base than to snout tip, last unbranched ray hard at base, softening toward tip, and with serrations along posterior edge. Anal-fin origin directly posterior to anus, reaching midway between anal-fin insertion to caudal fin base. Caudal-fin bifurcate. Lateral-line complete and curved, descending to above pectoral-fin rays from posterior margin of operculum and ascending to body midline above anal-fin base where extends to end of caudal peduncle. Scales small. Lateralline scales larger than other scales. Lateral-line scale rows 59���64; scale rows above lateral line 22���24; scale rows below lateral line 13; circumpeduncular scale rows 38. Predorsal scales irregularly arranged and difficult to count accurately. Coloration in alcohol.���Specimens were fixed in 10 % formalin and then preserved in 75 % alcohol. Dorsum dark grayish, abdomen light yellowish; no spots or blotches on body, head or fins; ventral aspect of caudal peduncle with very light black strip along midline from top of anus to base of caudal fin. Pectoral, dorsal and caudal fins grayish; anal-fin light grayish; pelvic-fin whitish. Distribution. Known only from a subterranean river of a cave in the town of Mulun, Huanjiang County, Guangxi Zhuang Autonomous Region, China. The subterranean river drains to the Longjiang River, a tributary of the Pearl River System (Fig. 2). Etymology. The name gracilicaudatus is a noun in apposition, derived from gracilis meaning slender and caudatus meaning tail, in reference to the narrow caudal peduncle and caudal fin. Discussion. Following the list of species of Sinocyclocheilus in Zhao et al. (2006), the new species can be distinguished from all other known species except for Sinocyclocheilus donglanensis, by having developed eyes, completely scaled body with a normal body shape, half-hard dorsal fin spine, curved lateral line with 59���63 lateralline scales, relatively short pectoral fin, 8 gill rakers and 8 predorsal vertebrae. Sinocyclocheilus gracilicaudatus is most similar to S. donglanensis. These two species are easily distinguished. Sinocyclocheilus gracilicaudatus has a more slender and longer caudal peduncle length (21.3���22.7 % vs. 16.8���20.4 % of SL) and narrower caudal peduncle depth (10.5 ���12.0% vs. 12.5���15.5 % of SL) relative to S. donglanensis (Fig. 3, Table 1). Interestingly, compared to S. donglanensis, Sinocyclocheilus gracilicaudatus has smaller eyes (eye diameter 5.8���8.3 % vs. 6.5���10.9 % of SL), but longer barbels (maxilla barbel length 16.6���24.3 % vs. 11.1���21.1 % of SL and rectal barbel length 19.5���21.6 % vs. 11.3���21.1 % of SL) (Fig. 4, 5; Table 1). Moreover, principle component analysis (PCA) of morphometric characters also reveals the two species differing primarily on the basis of three additional characters, including length of the maxilla and rictal barbels and length of the lower jaw (Fig. 6, Table 2). PC I PC II Standard length 0.2807 - 0.0107 Body depth 0.3278 0.1061 Predorsal length 0.2849 0.0087 Distance from head end to dorsal fin insertion (dorsal view) 0.319 - 0.0048 Sinocyclocheilus gracilicaudatus is also distributed allopatrically from S. donglanensis. The former species occurs only in a cave and the subterranean river of the Longjiang River system, a tributary of the Pearl River system. Whereas Sinocyclocheilus donglanensis occurs in the Hongshuihe River system, another tributary of the Pearl River system. Based on morphology and DNA sequences, the genus Sinocyclocheilus could be divided into four clades, given the appellations ��� jii ���, ��� angularis ���, ��� cyphotergous ���, and ��� tingi ��� (names of clades from species names representative of each clade.) Species of each clade have similar characteristics across each clade and they each have their own unique distributions with only very narrow overlap between the distributions of clades angularis and cyphotergous (Zhao & Zhang, 2009). Species of the ��� jii ��� clade have soft dorsal fin spines. Species of the ��� angularis ��� clade have a horn-like structure on the nape. Most species of the ��� tingi ��� clade have more than 70 lateral-line scale rows. Given the number of lateral-line scales (59���63), the new species is hypothesized to belong to the ��� cyphotergous ��� clade, although it does not have typical dorsal protuberance similar to a humpback (Romero, et al., 2009; Zhao & Zhang, 2009). The distribution of the new species is also in the range of the ��� cyphotergous ��� clade. Comparative materials. Sinocyclocheilus donglanensis: ASIZB 94976, holotype, 98.1mm SL, ASIZB 74217, 74218, 94747, 94748 (4 specimens), paratypes, 53.2���123.9mm SL, Zhujiang River basin: Hongshuihe River, Gongping Village, Taiping Town, Donglan County, Guangxi Zhuang Autonomous Region, China; 7 Oct 2002, by C. G. Zhang and K. Watanabe., Published as part of Wang, Dan, Zhao, Yahui, Yang, Junxing & Zhang, Chunguang, 2014, A new cavefish species from Southwest China, Sinocyclocheilus gracilicaudatus sp. nov. (Teleostei: Cypriniformes: Cyprinidae), pp. 583-590 in Zootaxa 3768 (5) on pages 584-589, DOI: 10.11646/zootaxa.3768.5.5, http://zenodo.org/record/227725, {"references":["Zhao, Y. & Zhang, C. (2009) Endemic Fishes of Sinocyclocheilus (Cypriniformes: Cyprinidae) in China --- Species diversity, cave adaptation, systematics and zoogeography. Science Press, Beijing, 271 pp.","Romero, A., Zhao, Y. & Chen, X. (2009) The Hypogean Fishes of China. Environmental Biology of Fishes, 86, 211 - 278. http: // dx. doi. org / 10.1007 / s 10641 - 009 - 9441 - 3"]}

Identifying ecological factors underlying primate group size has been a central theme in primate behavioral ecology. The ecological constraints model proposes that increased group size leads to enhanced within-group feeding competition, necessitating increased travel to encounter additional or more productive feeding sites. Over the course of three years, we studied the largest known group (80 individuals) of Trachypithecus crepusculus (Indo-Chinese gray langur) for 1738 hours during 213 days (including 96 full day follows) in Wuliangshan, China. During this period, group size increased from 81 individuals to over 90 individuals. The group consumed plant parts from 27 ± 8 (range: 15-51) species per month, and a total 148 plant species during the study. Based on time spent feeding, the diet was similar (54.2% leaves and 32.1% fruit and seeds) to that reported for other colobines. Despite occupying a home range several times larger than other groups of Trachypithecus, we found no evidence of an increase in daily path length with increasing group size, and the group's time budget and daily path length remained relatively constant despite marked monthly changes in dietary pattern (e.g. time spent exploiting fruit and seeds vs. buds and young leaves, vs. mature leaves). These results are inconsistent with many of the predictions of the ecological constraints model. Rather, our data suggest that high dietary diversity and the ability to exploit difficult to digest foods enabled Indo-Chinese gray langurs to reduce opportunities for feeding competition associated with increased group size.