Distinguishing ten sympatric species of fiddler crab (Decapoda: Ocypodidae) using a suite of phenotypic characteristics

Ten species of fiddler crab are reported inhabiting the intertidal zone of a shore on Kaledupa Island, Indonesia. This is one of the highest recorded numbers of fiddler crab species living in sympatry, equating to over two-thirds of those known from the Wallacea biogeographic region and more than half of all those recorded from Indonesia. The descriptions to identify and distinguish these ten species are provided using a suite of characters e.g., carapace, major cheliped, male gonopods, gastric mills, life colouration in males and females, and notes on their ecology and distribution. Specimens were observed and collected in the Wakatobi National Park, near the village of Ambeua on Kaledupa island, Sulawesi Tenggara, Indonesia. Gastric mills are described for the first time for Gelasimus jocelynae, Paraleptuca crassipes, Tubuca coarctata, T. demani and T. dussumieri. A tabulation of anatomical features and colouration for all species in this study is provided as a support for field studies. It identifies features that support the recently proposed taxonomic revision of fiddler crabs by Shih et al. (2016).

Description of a second deep-water species in the alpheid shrimp genus Bannereus Bruce, 1988 (Malacostraca: Caridea)

Bannereus chani sp. nov. (Caridea: Alpheidae) is described based on a single female specimen collected off south-eastern Taiwan, at a depth of 301–356 m, being the second only species in the genus Bannereus Bruce, 1988. The ovigerous female holotype of the new species differs from the female holotype of B. anomalus Bruce 1988, the type species of the genus, by a series of important morphological characters, for instance, on the major cheliped and third pereiopod, strongly indicating that they represent two distinct species. The non-type male specimen tentatively identified as B. anomalus by Bruce (1988) may well belong to the new species, since it differs from the holotype of B. anomalus essentially by the same criteria as the female holotype of B. chani sp. nov. In addition, B. anomalus is newly recorded from the New Caledonian side of the Coral Sea.

A new species of Biffarius Manning & Felder, 1991 (Decapoda: Axiidea: Callianassidae) from the intertidal coast of northeastern Brazil

A new species of intertidal ghost shrimp, Biffarius botterae, is described from Maranhão and Ceará in northeastern Brazilian coast. Diagnostic features of the new species include: (1) antennular peduncle shorter than antennal peduncle; (2) male major cheliped massive; (3) male pleopod 2 uniramous, vestigial; (4) uropodal endopod widening distally, inner lateral margin convex; and (5) anterodorsal plate of uropodal exopod absent. Biffarius Manning & Felder, 1991, now consists of four species: B. biformis (Biffar, 1971), B. botterae sp. nov., B. delicatulus Rodrigues & Manning, 1992, and B. limosus (Poore, 1975). A key to the species of Biffarius is provided.

A new species of Alpheus (Crustacea, Decapoda, Alpheidae) from the Arabian Sea, Kerala, India

A new species of Alpheus, A. samudra nov. sp., is described from the bycatch of trawlers operating between 275–375 m depth on the Quilon Bank (Kerala, India). The new species belongs to the brevirostris group, but can be easily distinguished from all but one species, by the extremely laterally compressed major cheliped. Alpheus samudra nov. sp. is very similar to A. leptocheles Banner & Banner, 1975 in the form of the major cheliped, but the proportions of the fingers to the palm and the shape of the fingers easily separate both species.

An updated checklist and key to the Zambian species of freshwater crabs, with the description of a new species of Potamonautes MacLeay, 1838 (Brachyura: Potamoidea: Potamonautidae)

A new species of the freshwater crab genus PotamonautesMacLeay, 1838 from Mporokoso, northern Zambia, southern Africa is described. Potamonautes caputanatisn. sp. is morphologically distinct from other species of this genus found in Zambia and its neighboring countries. The new species is recognised by a unique combination of morphological characters of the carapace, thoracic sternum, major cheliped, and adult male first gonopod. Illustrations of P. caputanatisn. sp. are provided and differences with congeners found elsewhere in Zambia and southern Africa are discussed. The addition of P. caputanatis n. sp. raises the number of species of freshwater crabs known to occur in Zambia to eleven. An updated checklist and key are provided to the Zambian species of freshwater crabs.

Description of a new alpheid shrimp, Automate isabelae sp. nov. (Decapoda, Caridea, Alpheidae) found in fish stomach contents of the lane snapper Lutjanus synagris (Linnaeus, 1758), from the west coast of Florida, Gulf of Mexico

A new species of caridean shrimp of the family Alpheidae, Automate isabelae sp. nov., found in stomach analysis contents of the lane snapper Lutjanus synagris (Linnaeus, 1758), from the Keys and SW coast of Florida, Gulf of Mexico, is described. The abdomen and portions of the cephalic appendages were damaged in holotype, but remainder of the body and the chelipeds, whith the most important diagnostic characters are in decent or perfect condition, the description was further supplemented based on intact morphological parts of the paratypes. The presence of tubercles on the dorsal and ventral margins of the major chela palm, shows this new species to be related to the eastern Pacific Automate rugosa Coutière, 1902. Both congeners can be easily discriminated by the proportions and shape of the third maxilliped, the proportions and ornamentation of the carpus, merus, and chela of the major cheliped, the ventral seta of the carpus of the minor cheliped, the presence of a distoventral spine on the propodi of third and fourth pereopods, the armature of dorsal surface of telson, and their geographical distribution. The description of this new species increases the number of worldwide valid species known of the genus Automate to 12.

A new deep-sea species of the snapping shrimp genus Alpheus Fabricius, 1798 (Decapoda: Caridea: Alpheidae) from Kagoshima Bay, Japan

A new species of the snapping shrimp genus Alpheus Fabricius, 1798, A. longipalma, is described and illustrated on the basis of material from Kagoshima Bay, Kyushu, Japan. It is referred to the A. brevirostris (Olivier, 1811) species group, and appears closest to A. macroskeles Alcock & Anderson, 1894, known with certainty from the Bay of Bengal and Andaman Sea, and A. talismani Coutière, 1898 from the eastern Atlantic. The greatly elongate minor cheliped in males, being subequal to or longer than the major cheliped with proportionally shorter dactylus distinguish the new species from A. macroskeles. The less elongate antennular peduncle and better-developed, rounded distal lamella of the antennal scaphocerite differentiate the new species from A. talismani. All specimens of the new species were trawled from depths greater than 200 m.

Morphological variability in populations of the fiddler crab Leptuca uruguayensis (Nobili, 1901) (Crustacea, Decapoda, Ocypodidae) from South America

A comparative study on size and shape of Leptuca uruguayensis was carried out between populations from Garças River, Brazil (BP), and Solís Grande River, Uruguay (UP). The size of the onset of sexual maturity was also estimated for UP. A total of 36 crabs BP and 387 crabs UP were analyzed. In the relative growth analysis, carapace width (CW) for both sexes, major cheliped length (LMC) for males and abdomen width (AW) for females were measured. The centroid size of carapace (1.40±0.19 cm BP and 1.88±0.30 cm UP) and cheliped (1.16±0.22 cm BP and 1.58±0.45 cm UP) differed significantly (p<0.001). The shape also differed significantly (p<0.001), having UP wider carapace than BP, rostrum projected forward and posterior margin positioned more anteriorly; the cheliped of UP was also wider than BP. In UP, males' CW ranged 4.28-19.5 mm and females' 2.53-16.3 mm CW; males' LMC ranged 1.79-31.60 mm and females' AW, 0.80-8.53 mm. The onset of sexual maturity of UP was estimated in 12.20 mm CW for males and 7.81 mm for females. These differences are likely related to abiotic variables acting distinctly in the two localities.

Synalpheus pinkfloydi sp. nov., a new pistol shrimp from the tropical eastern Pacific (Decapoda: Alpheidae)

A new, conspicuously coloured species of the alpheid genus Synalpheus Spence Bate, 1888, is described based on material collected on the Pacific coast of Panama. Synalpheus pinkfloydi sp. nov. is closely related to the western Atlantic S. antillensis Coutière, 1909, the two taxa being transisthmian, cryptic sister species. Both species are characterised by the distal areas of their major and minor chelae coloured in an intense, almost glowing pink-red. The morphological differences between S. pinkfloydi sp. nov. and S. antillensis Coutière, 1909 are subtle, being limited to the slightly different proportions of the merus of both chelipeds, distodorsal armature of the major cheliped merus, relative length of the antennal scaphocerite, and body size. However, they are genetically different with a 10.2% sequence divergence in COI. Based on molecular clock estimates, these transisthmian taxa diverged around 6.8–7.8 mya, i.e. well before the final closure of the Isthmus of Panama 2.5–3 mya.