New Species Of Freshwater Crab Research Articles

Morphological and molecular evidence for a new species of freshwater crab of the genus Sudanonautes Bott, 1955 (Brachyura: Potamoidea: Potamonautidae) from Cameroon, with notes on its ecology.

A new species of freshwater crab of the genus Sudanonautes Bott, 1955, is described from the tropical rainforests of Edea and Tiko in southern Cameroon, Central Africa. Sudanonautes tiko n. sp. is recognized by a unique combination of characters of the carapace, thoracic sternum, chelipeds, and male first gonopod, and by distinct mtDNA sequences for two loci (COI and 16S rRNA). A diagnosis, illustrations, and a tree of phylogenetic relationships based on mtDNA sequences are provided, along with a comparison to similar species from the region. Brief notes are provided on the ecology of the new species and of three other species of Sudanonautes collected during this study.

A new species of freshwater crab of the genus Himalayapotamon Pretzmann, 1966 (Decapoda, Brachyura: Potamidae: Potaminae) from Uttarakhand, northern India.

A new species of potamid freshwater crab, Himalayapotamon garhwalense n. sp., is described from a stream near Khanda in Pauri Garhwal district of Uttarakhand, India. The new species is differentiated from all congeners by a suite of carapace and gonopod features, including the short, stout and conical G1 terminal joint with gradually tapered distal portion. Himalayapotamon Pretzmann, 1966, is now represented by 11 species including H. garhwalense n. sp. An identification key to the species in the genus is provided.

Redescription of Potamonautes sidneyi (Rathbun, 1904) (Decapoda, Potamonautidae) and description of a new congeneric species from KwaZulu-Natal, South Africa.

A new species of freshwater crab, Potamonautes danielsi sp. n., is described from the southern region of the KwaZulu-Natal Province, South Africa. Potamonautes danielsi most closely resembles Potamonautes sidneyi which is re-described here, but can be distinguished by a suite of key morphological characters including carapace shape and width, slim pereopods, inflated propodi of the chelipeds, and the shape and terminal segment length:subterminal segment length ratio of the 1st gonopod. In a previous study (Gouws et al. 2015), a 9.2–11.8 % divergence was found in the mitochondrial COI and 16S genes of the Potamonautes sidneyi clade, allowing for the delineation of a new species. Despite the clear molecular distinction between the two species, it is difficult to separate them based on individual morphological characters, as there is a great deal of overlap even among key features. The new species is found in slow-moving mountain streams and pools at high altitudes between Umhlanga and Mtamvuna, in KwaZulu-Natal.

Three new species of freshwater crabs of the genus Pseudothelphusa (De Saussure, 1857) (Crustacea: Decapoda: Pseudothelphusidae) from Mexico.

Three new species of freshwater crabs of the genus Pseudothelphusa (De Saussure, 1857) from south-central Mexico are described: Pseudothelphusa acahuizotla n. sp., P. ixtapan n. sp., and P. purhepecha n. sp. The new species are included in Pseudothelphusa due to a male gonopod with torsion and the presence of the characteristic mesial process and caudomarginal projection. Pseudothelphusa acahuizotla n. sp. is morphologically similar to P. belliana Rathbun, 1898, but can be distinguished by the relative size of the distal lobe of the caudomarginal projection and by the presence of a conical tooth on the caudal surface of the mesial process of the male gonopod. Pseudothelphusa ixtapan n. sp. is similar to P. dilatata Rathbun, 1898, and P. morelosis Pretzmann, 1968, and can be distinguished by a mesial process of the male gonopod with only one lateral tooth and an inferior margin with small teeth. Pseudothelphusa puerhepechae n. sp. exhibits a mesial process of the male gonopod with two triangular spines on its lateral margin, a character that with some variations is present in P. nayaritae Álvarez & Villalobos, 1994, P. rechingeri Pretzmann, 1965, P. lophophallus Rodríguez & Smalley, 1969, and P. parabelliana Álvarez 1989; but it can be distinguished by the separation and shape of the two spines of the mesial process and the shape of the lobes of the caudomarginal projection. With the new species described herein there are now 29 species in the genus Pseudothelphusa.

Sundathelphusa miguelito, a new species of freshwater crab from the southern Philippines (Brachyura, Gecarcinucidae)

A new species of the freshwater crab genus Sundathelphusa Bott, 1969 (Gecarcinucidae) is described from the island of Mindanao in the southern Philippines. The Philippine Islands host the greatest species diversity of this genus, although only four species were previously known from Mindanao. The new species is most similar to S. mistio (Rathbun, 1904) and S. montanoanus (Rathbun, 1904) in the general carapace outline and leg proportions, but it can be distinguished by features of the carapace, thoracic sternum and gonopods. With this discovery, there are now 29 species of Sundathelphusa known from the Philippines.

A new and endangered species of Kingsleya Ortmann, 1897 (Crustacea:Decapoda: Brachyura: Pseudothelphusidae) from Ceará, northeastern Brazil.

A new species of freshwater crab, Kingsleya attenboroughi n. sp., from the Arajara district, Ceará state, Brazil, is described and illustrated. The new species differs from congeners by having a short apical plate in the first gonopod, with anteriorly directed lobes and proximally angular; proximal lobe of the apical plate with conspicuous semicircular protuberance in mesial and sternal views; marginal process protruded, projecting mesially in sternal view and subquadrate in mesial view; and field of apical spines narrow, tapering distally, with small spines concentrated proximally. Opportunity is taken to illustrate K. gustavoi Magalhães, 2005, the closest allied species of K. attenboroughi n. sp. A key for the species of Kingsleya Ortmann, 1897 is provided.

Yuebeipotamon calciatile, a new genus and new species of freshwater crab from southern China (Crustacea, Decapoda, Brachyura, Potamidae).

A new genus and species of freshwater crab, Yuebeipotamon calciatile gen. n., sp. n., is described from southern China. While the carapace features are superficially similar to species of Sinopotamon Bott, 1967, Longpotamon Shih, Huang & Ng, 2016, and Tenuilapotamon Dai, Song, Li, Chen, Wang & Hu, 1984, the new genus possesses a distinctive combination of carapace, ambulatory leg, male thoracic sternal, male abdominal, and gonopodal characters that distinguish it from these and other genera. Molecular evidence derived from the mitochondrial 16S rDNA supports the establishment of a new genus.

A new species of freshwater crab of the genus Tiwaripotamon Bott, 1970 (Crustacea, Brachyura, Potamidae) from northern Vietnam and southern China

A new species of freshwater crab of the genus Tiwaripotamon Bott, 1970 (Crustacea, Brachyura, Potamidae) from northern Vietnam and southern China

Two new species of freshwater crabs from the highlands of northern Uganda, East Africa and a redescription of Potamonautes amalerensis (Rathbun, 1935) stat. rev. from Mount Kadam (Brachyura: Potamoidea: Potamonautidae)

Two new species of potamonautid freshwater crabs are described from the Imatong Mountains and Mount Moroto in northern Uganda, East Africa, and a third highland species, Potamonautes amalerensis (Rathbun, 1935) stat. rev. from Mount Kadam is re-diagnosed based on examination of the holotype. All three species are endemic to a different mountain range and their collection localities indicate a distinct preference for higher altitudes. Diagnoses, illustrations and distribution maps are provided for these taxa, and they are compared to similar species from the region. The conservation status of all three species is discussed.

Potamonautes gorongosa, a new species of potamonautid freshwater crab (Decapoda, Brachyura) from Mozambique, southeastern Africa

A new species of the freshwater crab genus Potamonautes MacLeay, 1838, is described from Gorongosa National Park in Sofala Province, Mozambique, southern Africa. Potamonautes gorongosa, new species, is morphologically and phylogenetically distinct from the other species of Potamonautes found in Mozambique and nearby countries, and is most closely related to Potamonautes mutareensis Phiri and Daniels, 2013, from eastern Zimbabwe. The new species differs from this species and its other congeners by a unique combination of morphological characters of the first gonopod, the anterior sternum, third maxilliped, and the major cheliped. Illustrations of P. gorongosa new species are provided, and differences with other species found in Mozambique and southeastern Africa are discussed.

A new species of freshwater crab of the genus Kingsleya Ortmann, 1897(Crustacea: Brachyura: Pseudothelphusidae) from Amazonia, Brazil.

A new species of freshwater crab, Kingsleya celioi, from the Brazilian Amazon (Pará State) is described and illustrated. The new species can be easily separated from their congeners by a suite of morphological characters, including the apical plate of the first gonopod large, widest medially in abdominal view, with single large spine-like outgrowth in midlength of mesial margin; distal, proximal lobes of apical plate unequal in size, distal lobe largest, tapering distally in lateral view.

Spiralothelphusa gibberosa, a new freshwater crab (Brachyura: Gecarcinucidae) from Thrissur district, Kerala, India.

A new species of freshwater crab, Spiralothelphusa gibberosa n. sp. is described from rice fields near Kizhoor in Thrissur district of Kerala in southern India. The new species is easily differentiated from its congeners by its first male pleopod (G1), which has a long, less strongly twisted terminal segment and distal portion of subterminal segment in addition to a setose hump on the outer margin of the non-twisted portion. Key to the species of the genus Spiralothelphusa Bott, 1968, is provided. We recognized S. wuellerstorfi (Heller, 1862), as a new record to Maharashtra based on specimens wrongly identified as S. hydrodroma (Herbst, 1794), by Pati & Sharma (2014).

Description of a new species of Potamonautes MacLeay, 1838, from the iSimangaliso Wetland Park, South Africa.

A new species of freshwater crab, Potamonautes isimangaliso sp. n., is described from the western shores of False Bay, Hluhluwe, within the iSimangaliso Wetland Park, South Africa. While bearing a superficial resemblance to Potamonautes lividus, the new species has been found to be genetically distinct, diverging from the former by 7.4–7.8% in mtDNA. Potamonautes isimangaliso most closely resembles Potamonautes lividus, but is distinguished by a unique suite of carapace characters, colouration, and size. The new species also lives in close association with oxygen-poor, fresh ephemeral pans, while the habitat of Potamonautes lividus is well above the surface water line of the closest water body. An updated identification key for the Potamonautes species of South Africa is provided.

Description of a new genus and new species of freshwater crab (Brachyura: Gecarcinucidae) from the Western Ghats, Kerala, India.

Freshwater crabs of the Western Ghats have been severely underestimated in their diversity.Since freshwater crabs have a small spatial scale endemism, many remote and poorly studied localities in the Western Ghats need to be surveyed. In this study, a new genus and new species is described. Arcithelphusa cochleariformis gen. et sp. nov. is described from Ondayangadi, Wayanad district, Kerala, India. The new genus and new species is exceptional among Indian freshwater crabs due to its squarish, highly arched carapace, appearing box-like in frontal view, and long, stout, spoon-shaped male first gonopod. With the current discovery, 14 genera and 36 species of gecarcinucid freshwater crabs are recognized in the Western Ghats of India. More new taxa can be expected from this exceptionally biodiversity-rich area if the necessary surveys are done.

One new genus and one new species of freshwater crabs (Decapoda, Brachyura, Potamidae) from the Southern part of Vietnam

Dalatomon gen. nov. Dang et Ho Diagnosis: crab is small in size, the length (l) under 30 mm, carapace trapezoid form, flat, upper surface smooth. Ischium maxilliped rectangular, merus almost rectangular, exopod long, reaching to 1/3 merus external margin. Male terminal segment of abdomen equilateral triangular, low with round top, lateral border straight, moderately longer than VI segment. GO1 terminal segment in male with dorsal, broad semicircular fold, extending to 2/3 length of this segment. Etymology: this genus name is derived from its type locality at Dalat (Lamdong province, west highland of Vietnam), in combination with the genus name Potamon. The gender is neuter. Type species: Dalatomon soni sp. nov. Dalatomon soni sp. nov. Dang et Ho Holotype: 1 male; Allotype, 1 female, collected from the stream at Dalat city (Lamdong province), Vietnam. Coll. 3 July, 2005; Paratype: 2 males, collected from Dalat city (Lamdong province). Coll 3 July, 2005, deposited in the Zoological Museum, Institute of Ecology and Biological resources, Hanoi-Vietnam. Diagnosis: crab is small in size, carapace largely transverse trapezoid, flat, upper surface smooth. Epibranchial tooth small. Anterolateral tooth not developed. Frontal margin moderately concave, Antero-lateral angle rounded, lateral margin oblique. Postfrontal, postorbital cristae cleared, undulated down, reaching to the basis of the epibranchian tooth. Postfrontal and postorbital bilobed swollen. Semilunar, H-shaped grooves distinct. Ischium maxilliped rectangular with groove in middle, exopod straigth, reaching to 1/3 merus external margin. Merus rectangular, flagella long reaching over merus upper margin. Male terminal segment of abdomen equilateral triangular, low with round top, lateral border straight, longer than VI segment. Subterminal segment of GO1 in male with basal part narrowly elongated. Terminal segment with dorsal, broad semicircular fold, located in the first half part, extending to 2/3 of this segment. Distal part of terminal segment cylinder-shaped, curved down tip truncate with upper distal angle produced as sharp, small, transparent projection. G2 long, slender, distal segment shorter than basal segment. Ambulatory legs slender, long. Remarks: Dalatomon soni sp. nov. is firstly found in Dalat city (Lamdong province), southern Vietnam. This species distributed in streams of highland mountainous areas but with small quantities. This new species is closely related to others species belonging to genera Laevimon, Donopotamon, Thaipotamon, Pudaengon, Rathbulamon, Phaibulamon, Pilosamon that are found in the Catba island (northern Vietnam) and in the basin of the Mekong river of southern Vietnam, Laos and Thailand. These species has the same characteristics such as terminal segment in GO1 of male with dorsal, broad semicircular fold but this new species differs from others by small size of carapace, the location of semicircular fold, the form of distal part of terminal segment and several different features as well. Table 1 Comparison of principal characteristics of Dalatomon gen. nov. with Donopotamon Dang et Ho 2005 and Laevimon Yeo et Ng., 2005 Characteristics of male Dalatomon Donopotamon Laevimon Size of carapace Small, the length less than 30 mm Big, the length more than 40 mm, even to 70 mm. Big, the length more than 40 mm. Carapace form Largely transverse trapezoid, flat, upper surface smooth. Largely transverse trapezoid, flat, upper surface smooth Anterolateral region rugose and granulose. Carapace distinctly transverse, high; dorsal surface strong convex longitudinally and transversely; smooth. Postorbital cristae Not sharp moderately oblique. Slightly sharp, horizontally straight. Uncleared. GO1 Subterminal segment with basal elongated. Terminal segment long 1/2 times length of subterminal segment, distal part curved down. Terminal segent with dorsal, broad semicircular fold, located in the first half part, extending to 2/3 of this segment. Terminal segment cylinder-shaped, tip truncate with upper distal angle produced as sharp, small, transparent projection. Subterminal segment with basal large, distal part narrow, neck-like. Terminal segment with dorsal, broad semicircular fold, occupying almost completely half distal part of this segment, establishing dove-head in shape. Subterminal segment with basal slender. Terminal segment short, about 1/3 times of subterminal segment. Terminal segment subcylindrical; tip truncate with inner distal angle produced as sharp, narrow projection. Hump-like, in proximal part, distinctly shorter than half length of terminal segment. Third maxilliped Ischium and merus rectangualar; exopod straight, reaching to 1/3 merus external margin. Flagellum long, reaching over merus upper margin; but shorter than merus width. Ischium rectangular; merus squarish; exopod straight, reaching to 1/3 merus external margin. Flagellum long, reaching over merus upper margin. Ischium broadly rectangular; merus squarish; upper angles rounded. Flagellum long, subequal to merus width. VII segment of the abdomen Equilateral triangular, low with round top, lateral border straight. Triangular; lateral border concave. Narrowly triangular; lateral border cocave at middle.

A new species of freshwater crab of the genus Sodhiana Yeo & Ng, 2012 (Decapoda: Brachyura: Gecarcinucidae) from southern Iran.

A new species of freshwater crab, Sodhiana iranica n. sp. (Decapoda: Brachyura: Gecarcinucidae), is described from Bastak, Iran. This is fourth species of Sodhiana Yeo & Ng, 2012, described, and is the second one known from Iran. It can be distinguished from congeners by the form of its carapace and the structure of the male first gonopod.

A new species of freshwater crab of the genus Microthelphusa Pretzmann, 1968 (Crustacea: Brachyura: Pseudothelphusidae) from the Amazon region of Guyana.

A new species of freshwater crab, Microthelphusa furcifer, is described and illustrated from the Potaro-Siparuni Kuribrong River in the Guyana Shield (Amazon region of Guyana). The new species can be easily separated from its congeners by the morphology of the first gonopod. The first gonopod of Microthelphusa meansi Cumberlidge, 2007, is illustrated to clarify some aspects of its morphology.

Dos nuevas especies de cangrejos de agua dulce (Brachyura: Pseudothelphusidae) de la Serranía de Los Paraguas, Cordillera Occidental de Colombia

Two new species of freshwater crabs of the genus Hypolobocera from Serranía de Los Paraguas, Cordillera Occidental, Colombia, are described. Hypolobocera solimani n. sp. is closely related to H. alata Campos 1989, but can be distinguished from it by smooth upper margin of third maxilliped merus, the size and shape of apex of first gonopod, and the internal lobe or papilla of spermatic channel, which is concave, raised, with ends with minute papillae or rounded tubercles. Hypolobocera triangula n. sp. is very similar to H. rotundilobata Rodríguez 1994, but differs from it by the shape and size of the lateral lobe, an oblique basal ridge of tubercles and by the apex of first gonopod. With the two new species, the total number of valid members of the genus Hypolobocera known from western Colombia or biogeographic Chocó is 20.

Recognition of two new species of freshwater crabs from the Seychelles based on molecular evidence (Potamoidea : Potamonautidae)

The Afrotropical freshwater crab genus Seychellum is endemic to the granitic Seychelles in the Indian Ocean (Mahé, Silhouette, Praslin, La Digue and Frégate). Here we describe two new cryptic species of Seychellum that represent two evolutionarily separate lineages of a previously monotypic genus. This raises to three the number of species of freshwater crabs known from Seychelles. Each species is endemic to either one island (Silhouette) or to a pair of islands (Mahé and Frégate, or Praslin and La Digue). The three species can be clearly distinguished as separate lineages by DNA analysis, haplotyping and examination of gonopod characters. The recognition of S. silhouette, sp. nov. (endemic to Silhouette) and S. mahefregate, sp. nov. (endemic to Mahé and Frégate) reduces the range of the type species, S. alluaudi (A. Milne-Edwards & Bouvier, 1893) to La Digue and Praslin. Both dispersal and vicariance may have played a role in shaping the present distribution patterns of the Seychellois freshwater crabs.

A new species of freshwater crab,Travancoriana granulatan. sp. (Brachyura: Gecarcinucidae) from the southern Western Ghats of India

A new species of freshwater crab of the genus Travancoriana Bott, 1969, is described from the southern Western Ghats, Eravikulam National Park, Idukki district, Kerala, India. The newly described species, Travancoriana granulata n. sp., is distinct from the other five known species of this genus in some morphological features like parallel lateral margins of the frontal, anteriorly placed broad epigastric cristae, the squarish sixth male abdominal somite, and gonopod structures. A key to the species of Travancoriana is provided. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)