Abstract

Four species of sesarmid crabs of the genus Nanosesarma Tweedie, 1950, have been reported from India: Nanosesarma andersoni (De Man, 1888), Nanosesarma batavicum (Moreira, 1903), Nanosesarma jousseaumei (Nobili, 1906), and Nanosesarma minutum (De Man, 1887). In the present study, one more species, Nanosesarma sarii Naderloo and Türkay, 2009 is reported for the first time from India along with the diagnosis and illustrations of the five Indian Nanosesarma species.

Keywords:
Brachyura; Goa; Gujarat; intertidal area; new record; West coast of India

INTRODUCTION

Tweedie (1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.) proposed a new genus, NanosesarmaTweedie, 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316., characterized by “distal part of the hind border of the ambulatory meri being spinate or denticulate”, for seven species: Nanosesarma andersoni (De Man, 1888De Man JG 1888. Report on the podophthalmous Crustacea of the Mergui Archipelago, collected for the Trustees of the Indian Museum, Calcutta, by Dr. John Anderson, F.R.S., Superintendent of the Museum. Part III. Journal of the Linnean Society of London (Zoology), 22: 129-176. DOI: 10.1111/j.1096-3642.1887.tb00027.x.
https://doi.org/10.1111/j.1096-3642.1887... ), Nanosesarma batavicum (Moreira, 1903Moreira C 1903. Nota appendice às contribuições para o conhecimento da fauna brazileira - Crustaceos do Brazil. Archivos do Museu Nacional do Rio de Janeiro, 12: 111-117, pl. 1. https://www.marinespecies.org/aphia.php?p=sourceget&id=377303
https://www.marinespecies.org/aphia.php?... ), Nanosesarma edamense (De Man, 1887De Man JG 1887. Uebersicht der indo-pacifischen Arten der Gattung Sesarma Say, nebst einer Kritik der von W. Hess und E. Nauck in den Jahren 1865 und 1880 beschriebenen Decapoden. Zoologische Jahrbücher, Abtheilung für Systematik, Geographie und Biologie der Thiere, 2: 639-722. https://biostor.org/reference/4033
https://biostor.org/reference/4033... ), Nanosesarma gordoni (Shen, 1935Shen CJ 1935. On some new and rare crabs of the families Pinnotheridae, Grapsidae and Ocypodidae from China. Chinese Journal of Zoology, 1: 19-40.), Nanosesarma minutum (De Man, 1887De Man JG 1887. Uebersicht der indo-pacifischen Arten der Gattung Sesarma Say, nebst einer Kritik der von W. Hess und E. Nauck in den Jahren 1865 und 1880 beschriebenen Decapoden. Zoologische Jahrbücher, Abtheilung für Systematik, Geographie und Biologie der Thiere, 2: 639-722. https://biostor.org/reference/4033
https://biostor.org/reference/4033... ), Nanosesarma nunongi Tweedie, 1950, and Nanosesarma vestitum (Stimpson, 1858Stimpson W 1858. Prodromus descriptionis animalium evertebratorum, quae in Expeditione ad Oceanum Pacificum Septentrionalem, a Republica Federata missa, Cadwaladaro Ringgold et Johanne Rodgers Ducibus, observavit et descripsit. Pars V. Crustacea Ocypodoidea. Proceedings of the Academy of Natural Sciences of Philadelphia, 10: 93-110. DOI:10.5962/bhl.title.51447
https://doi.org/10.5962/bhl.title.51447... ). Serène (1967Serène R 1967. Sur deux espéces nouvelles de Brachyoures (Crustacés Décapodes) et sur une troisième peu connue récoltées dans la région Malaise. Bulletin du Muséum National d’histoire Naturelle, Série 2 , 38 (6): 817-827. https://biostor.org/reference/240598
https://biostor.org/reference/240598... ) described Nanosesarma tweedieiSerène, 1967 Serène R 1967. Sur deux espéces nouvelles de Brachyoures (Crustacés Décapodes) et sur une troisième peu connue récoltées dans la région Malaise. Bulletin du Muséum National d’histoire Naturelle, Série 2 , 38 (6): 817-827. https://biostor.org/reference/240598
https://biostor.org/reference/240598... from Mersing, Malaysia, with a “densely setose, elongate carapace and setose outer surface of chelipeds”, and suggested a morphological affinity with N. minutum.

Serène and Soh (1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416.) proposed to divide Nanosesarma into two subgenera: Nanosesarma (Nanosesarma) (type species N. minutum) and Nanosesarma (Beanium) Serène and Soh, 1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416. (type species N. batavicum). In the same study, they synonymized Sesarma jousseaumeiNobili, 1906Nobili G 1906. Diagnoses préliminaires de 34 espéces et varietés nouvelles, et de 2 genres nouveaux de Décapodes de la Mer Rouge. Bulletin du Muséum d’Histoire Naturelle, Paris, 1 er série, 6 (for 1905) 393-411. and N. gordoni with N. minutum. They also transferred Sesarma pontianacenseDe Man, 1895De Man JG 1895. Berichte uber die von Herrn Schiffscapitän Storm zu Atjeh, an den westlichen Küsten von Malakka, Borneo und Celebes sowie in der Java-See gesammelten Decapoden und Stomatopoden. Zoologische Jahrbücher, Abtheilung für Systematik, Geographie und Biologie der Thiere, 8 (4): 485-609. DOI: 10.5962/bhl.title.16084.
https://doi.org/10.5962/bhl.title.16084.... to Nanosesarma and synonymized N. tweediei with the former species. However, they were unable to determine the subgeneric position of N. vestitum.

Subsequently, Holthuis (1977Holthuis LB 1977. The Grapsidae, Gecarcinidae and Palicidae (Crustacea: Decapoda: Brachyura) of the Red Sea. Israel Journal of Zoology, 26: 141-192. DOI: 10.1080/00212210.1977.10688447
https://doi.org/10.1080/00212210.1977.10... ) provided a short introduction to the genus Nanosesarma wherein he disapproved of the division of Nanosesarma into two subgenera by Serène and Soh (1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416.) stating that “the differences given by Serène and Soh (1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416.) for their two subgeneric taxa are rather vague and not too clear cut”. Moreover, he believed that the division of the genus into two subgenera on the basis of the male pleon was inadequate, since this character was neither included in original descriptions (e.g., N. edamense; N. batavicum) nor clearly described (e.g., N. andersoni; N. nunongi).

Recently, Ng et al. (2008Ng PKL; Guinot D and Davie PJF 2008. Systema Brachyurorum, part I. An annotated checklist of extant brachyuran crabs of the world. Raffles Bulletin of Zoology, Supplement, 17: 1-286.) treated BeaniumSerène and Soh, 1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416. [as Nanosesarma (Beanium)] as a junior subjective synonym of NanosesarmaTweedie, 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.. Subsequently they listed nine extant species of Nanosesarma, and treated Sesarma gordoni and Sesarma barbimanaCano, 1889Cano G 1889. Viaggio della R. Corvetta Vettor Pisani attorno al globo: Crostacei Brachiuri ed Anomuri. Bollettino Società dei Naturalisti in Napoli, 3: 169-268. as synonyms under N. minutum, and rejected the subgeneric classification of Serène and Soh (1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416.). Currently, Nanosesarma comprises 10 valid species (Ng et al., 2008Ng PKL; Guinot D and Davie PJF 2008. Systema Brachyurorum, part I. An annotated checklist of extant brachyuran crabs of the world. Raffles Bulletin of Zoology, Supplement, 17: 1-286.; Naderloo and Türkay, 2009Naderloo R and Türkay M 2009. A new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf. Journal of Natural History, 43 (47-48): 2911-2923. DOI: 10.1080/00222930903219996.
https://doi.org/10.1080/0022293090321999... ) inhabiting intertidal habitats across the Indo-Pacific regions (Serène and Soh, 1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416.), of which four species: N. andersoni, N. batavicum, N. jousseaumei and N. minutum have been reported from India (Trivedi et al., 2018Trivedi JN; Trivedi DJ; Vachhrajani KD and Ng PKL 2018. An annotated checklist of the marine brachyuran crabs (Crustacea: Decapoda: Brachyura) of India. Zootaxa, 4502 (1): 1-83. DOI: 10.11646/zootaxa.4502.1.1.
https://doi.org/10.11646/zootaxa.4502.1.... ). In the present study, we record the presence of one more species, Nanosesarma sariiNaderloo and Türkay, 2009Naderloo R and Türkay M 2009. A new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf. Journal of Natural History, 43 (47-48): 2911-2923. DOI: 10.1080/00222930903219996.
https://doi.org/10.1080/0022293090321999... , for the first time from India. Further, a detailed diagnosis of all five species of Nanosesarma occurring in India, along with their illustrations and morphological comparisons, is provided here to facilitate proper identification.

MATERIAL AND METHODS

The specimens were collected from the coastal regions of Gujarat and Goa States of India. The specimens examined were stored in a 5 % formalin solution and deposited in the Marine Biology Laboratory, Department of Marine Sciences, Goa University, Goa, India (GUMSIS) and Zoological Reference Collection, Department of Life Sciences, Hemchandracharya North Gujarat University, Patan, Gujarat, India (LFSC.ZRC). The terminology used in the description follows Davie et al. (2015Davie PJF, Guinot D, and Ng PKL 2015. Systematics and Classification of Brachyura. p. 1049-1130. In: P Castro; PJF Davie; D Guinot; F Schram and C Von Vaupel Klein (Eds.), Treatise on Zoology - Anatomy, Taxonomy, Biology - The Crustacea, complementary to the volumes translated from the French Traite de Zoologie, 9(C) (71-18), Decapoda: Brachyura (part 1). Leiden and Boston, Brill. DOI: 10.1163/9789004190832_021
https://doi.org/10.1163/9789004190832_02... ). The following abbreviations are used: CL = carapace length; CW = carapace width; P2-5 = second to fifth walking legs respectively; PW = pleonal width; G1 = male first gonopod; coll. = collector. All the measurements are expressed in millimeters (mm).

SYSTEMATICS

Family Sesarmidae Dana, 1851Dana JD 1851. On the classification of the Crustacea Grapsoidea. The American Journal of Science and Arts, 2 (12): 283-291. https://www.biodiversitylibrary.org/part/244088#/summary
https://www.biodiversitylibrary.org/part...

Genus Nanosesarma Tweedie, 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.

Nanosesarma andersoni ( De Man, 1888De Man JG 1888. Report on the podophthalmous Crustacea of the Mergui Archipelago, collected for the Trustees of the Indian Museum, Calcutta, by Dr. John Anderson, F.R.S., Superintendent of the Museum. Part III. Journal of the Linnean Society of London (Zoology), 22: 129-176. DOI: 10.1111/j.1096-3642.1887.tb00027.x.
https://doi.org/10.1111/j.1096-3642.1887... )

(Figs. 1A, 2, 7A, B)

Sesarma andersoniDe Man, 1888De Man JG 1888. Report on the podophthalmous Crustacea of the Mergui Archipelago, collected for the Trustees of the Indian Museum, Calcutta, by Dr. John Anderson, F.R.S., Superintendent of the Museum. Part III. Journal of the Linnean Society of London (Zoology), 22: 129-176. DOI: 10.1111/j.1096-3642.1887.tb00027.x.
https://doi.org/10.1111/j.1096-3642.1887... : 172, pl. 12, figs. 1-4. - Alcock, 1900Alcock A 1900. Materials of a carcinological fauna of India, No. 6. The Brachyura Catometopa, or Grapsoidea. Part II (2). Journal of the Asiatic Society of Bengal 69(II), Natural Science, 3: 279-456. http://www.archive.org/stream/materialsforcarc00alco#page/n7/mode/2up
http://www.archive.org/stream/materialsf... : 418.

Sesarma (Parasesarma) andersoni - Tesch, 1917Tesch JJ 1917. Synopsis of the genera Sesarma, Metasesarma, Sarmatium and Clistocoeloma, with a key to the determination of the Indo-Pacific species. Zoologische Mededelingen, 3 (2-3): 127-260. DOI: 10.5962/bhl.title.10640.
https://doi.org/10.5962/bhl.title.10640.... : 129.

Nanosesarma andersoni - Tweedie, 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.: 312, fig. 1d, e.

Nanosesarma (Beanium) andersoni - Serène and Soh, 1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416.: 394.

Material examined. 10 males (CL: 4.4-4.8 mm, CW: 5.9-6.5 mm), 7 females (CL: 2.9-4.3 mm, CW: 4.0-5.8 mm), LFSC.ZRC-185, India, Goa, Chapora Estuary (15°37'21"N 73°44'45"E), coll. Mithila Bhat, 13 April 2016.

Diagnosis. Carapace quadrangular, glabrous, 1.34 times wider than long; lateral margins slightly concave, subparallel posteriorly; dorsal surface covered with scattered pits, setal tufts and sparsely placed setae; protogastric and mesogastric regions delimited by inconspicuous grooves. External orbital tooth broadly triangular followed by rudimentary epibranchial tooth. Several oblique, low, setose granulated striations extending across branchial regions (Figs. 1A, 2A). Frontal margin wide, indistinctly bilobed, frontal lobes separated by shallow depression; 4 inconspicuous postfrontal lobes covered with setose patches, separated by longitudinal grooves (Fig. 2A). Basal antennal article long (Fig. 2B), reaching distal margin of first article.

Third maxillipeds with distinct rhomboidal gap when closed; ischium subrectangular, slightly longer than wide, 1.27 times longer than merus, with oblique setose ridge; merus subovate, 1.01 times as wide as long, with oblique setose ridge. Exopod slender, flattened, with long flagellum (Fig. 2C).

Chelipeds subequal, massive; palm massive (Fig. 2D), surfaces rugose, dorsal surface with two oblique pectinate crests and 4 or 5 oblique granular ridges (Fig. 2E); outer surface pitted, covered with discreet granular striations on posterior half and scattered granules anteriorly, thin granular line on lower half commencing on pollex and extending posteriorly to carpal junction; inner surface sparsely granulated. Fingers (dactylus and pollex) massive, curved, with rounded spatulate tips, gaping when closed. Male cheliped dactylus short, with row of 13 or 14 small smooth transverse tubercles and proximal granules on dorsal surface; inner surface with proximal granular patch. Cutting edge of dactylus with 3 large and 2 small teeth, and large subdistal tooth, pollex with large subdistal tooth, followed by 3 small, 1 large median teeth and 4 proximal teeth (Fig. 2D).

P2-5, compressed, shorter than chelipeds. P2 short, P3 and P4 subequal, P5 short. P4 and P5 meri flattened, wider distally. Carpi ventral surfaces with median longitudinal granular ridge. P4 and P5 carpi and propodi without dense setae. Propodi about twice as long as wide, posterior margins with distal spine and few long bristles, ventral surface with inconspicuous oblique groove. Dactyli smooth, tip corneous, slightly curved, dorsal margin with 2 pairs of slender subdistal spines and ventral margin with 1 pair of subdistal spines (Fig. 2F).

Male pleon narrow, bluntly triangular, surface pitted; lateral margins finely granulated, densely setose; telson 1.03 times as long as wide, 1.69 times as long as pleomere 6 (Fig. 2G). Female pleon wide, rounded, pleomere 6 with concave distal margin; telson pentagonal, wider than long, partially sunken into distal margin of pleomere 6 (Fig. 2H).

G1 long, straight, distal part corneous, flattened, slightly curved, medially notched, flanked by thick bristles, groove at base of tip extends along ventral surface to G1 (Fig. 7A, B).

Remarks. The specimens examined in the present study resemble De Man’s (1888De Man JG 1888. Report on the podophthalmous Crustacea of the Mergui Archipelago, collected for the Trustees of the Indian Museum, Calcutta, by Dr. John Anderson, F.R.S., Superintendent of the Museum. Part III. Journal of the Linnean Society of London (Zoology), 22: 129-176. DOI: 10.1111/j.1096-3642.1887.tb00027.x.
https://doi.org/10.1111/j.1096-3642.1887... ) description of his Sesarma andersoni, differing in the presence of a distinct subdistal spine on the anterior margin of P2-P5 meri. Morphological comparison with other Indian congeneric species is provided in Tab. 1.

Distribution. Nanosesarma andersoni was originally described from Mergui Archipelago (De Man, 1888De Man JG 1888. Report on the podophthalmous Crustacea of the Mergui Archipelago, collected for the Trustees of the Indian Museum, Calcutta, by Dr. John Anderson, F.R.S., Superintendent of the Museum. Part III. Journal of the Linnean Society of London (Zoology), 22: 129-176. DOI: 10.1111/j.1096-3642.1887.tb00027.x.
https://doi.org/10.1111/j.1096-3642.1887... ; Alcock, 1900Alcock A 1900. Materials of a carcinological fauna of India, No. 6. The Brachyura Catometopa, or Grapsoidea. Part II (2). Journal of the Asiatic Society of Bengal 69(II), Natural Science, 3: 279-456. http://www.archive.org/stream/materialsforcarc00alco#page/n7/mode/2up
http://www.archive.org/stream/materialsf... ), and later reported from Malaysia, Singapore, (Tweedie, 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.), Japan (Komai et al., 2004Komai T; Nagai T; Yogi A; Nasure T; Fujita Y and Shokita S 2004. New records of four grapsoid crabs (Crustacea: Decapoda: Brachyura) from Japan, with notes on four rare species. Natural History Research, 8 (1): 33-63.) and India (Trivedi et al., 2018Trivedi JN; Trivedi DJ; Vachhrajani KD and Ng PKL 2018. An annotated checklist of the marine brachyuran crabs (Crustacea: Decapoda: Brachyura) of India. Zootaxa, 4502 (1): 1-83. DOI: 10.11646/zootaxa.4502.1.1.
https://doi.org/10.11646/zootaxa.4502.1.... ). In India, it is known from Goa (Dev Roy and Bhadra, 2008Dev Roy MK and Bhadra S 2008. Marine and estuarine crabs (Crustacea: Decapoda: Brachyura) p. 109-154. In: Director, Zoological Survey of India, Kolkata (Ed.), Fauna of Goa, State Fauna Series, 16. Kolkata, India, Zoological Survey of India.; present study), Kerala (Devi et al., 2015Devi LP; Joseph A and Khan AS 2015. Diversity of brachyuran crabs of Cochin backwaters, Kerala, India. p. 75-86. In: Venkataraman K and Sivaperuman C. (Eds.), Marine Faunal Diversity in India, Taxonomy, Ecology and Conservation. Elsevier, Amsterdam. DOI: 10.1016/B978-0-12-801948-1.00005-7.
https://doi.org/10.1016/B978-0-12-801948... ), Tamil Nadu (Ravichandran and Kannupandi, 2007Ravichandran S and Kannupandi T 2007. Biodiversity of crabs in Pichavaram mangrove environment. p. 331-340. In: Director Zoological Survey of India, Kolkata (Ed.), National Symposium on Conservation and Validation of Marine Biodiversity. https://doi.org/10.3923/ijzr.2008.113.118
https://doi.org/10.3923/ijzr.2008.113.11... ), and Andaman and Nicobar Islands (Dev Roy and Das, 2000Dev Roy MK and Das AK 2000. Taxonomy, ecobiology and distribution pattern of the Brachyuran crabs of mangrove ecosystem in Andaman Islands. Records of Zoological Survey of India, Occasional Paper, 185: 1-211.).

Nanosesarma batavicum ( Moreira, 1903Moreira C 1903. Nota appendice às contribuições para o conhecimento da fauna brazileira - Crustaceos do Brazil. Archivos do Museu Nacional do Rio de Janeiro, 12: 111-117, pl. 1. https://www.marinespecies.org/aphia.php?p=sourceget&id=377303
https://www.marinespecies.org/aphia.php?... )

(Figs. 1B, 3, 7C, D)

Sesarma barbimana - De Man, 1890De Man JG 1890. Carcinological studies in the Leyden Museum, No. 4. Notes from the Leyden Museum, 12: 49-126, pls. 3-6.: 104, pl. 6, fig. 13.

Sesarma batavicaMoreira, 1903Moreira C 1903. Nota appendice às contribuições para o conhecimento da fauna brazileira - Crustaceos do Brazil. Archivos do Museu Nacional do Rio de Janeiro, 12: 111-117, pl. 1. https://www.marinespecies.org/aphia.php?p=sourceget&id=377303
https://www.marinespecies.org/aphia.php?... : 117 (nom. nov.). - Tweedie, 1940Tweedie MWF 1940. New and interesting Malaysian species of Sesarma and Utica (Crustacea Brachyura). Bulletin of the Raffles Museum, 16: 88-113.: 90, fig. 1.

Sesarma batavicum - Kemp, 1915Kemp S 1915. Fauna of the Chilka Lake No. 3: Crustacea Decapoda. Memoirs of the Indian Museum, 5: 199-325. DOI:10.5962/bhl.title.10414
https://doi.org/10.5962/bhl.title.10414... : 238, pl. 12, fig. 7.

Sesarma (Parasesarma) batavica - Tweedie, 1936Tweedie MWF 1936. On the Crabs of the Family Grapsidae in the Collection of the Raffles Museum. Bulletin of the Raffles Museum, 12: 44-71.: 62.

Nanosesarma batavica - Tweedie, 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.: 311.

Nanosesarma (Beanium) batavicum - Serène and Soh, 1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416.: 394.

Material examined. 1 male (CL: 4.8 mm, CW: 6.6 mm), GUMSIS1, India, Goa, Verem (15°29'74"N 73°48'20"E), coll. Mithila Bhat, 9 April 2014.

Description. Carapace quadrangular, 1.35 times wider than long, with slightly concave, converging lateral margins; dorsal surface covered with scattered pits, prominent setal tufts on post-frontal lobes, protogastric and anterior branchial regions, and sparsely placed setae on posterior half of carapace. External orbital tooth triangular. Several oblique, low, setose granulated striations extending across branchial regions (Figs. 1B, 3A). Frontal lobes separated by shallow depression; 4 inconspicuous post-frontal lobes covered with setose patches, separated by longitudinal grooves (Fig. 3A).

Third maxillipeds with distinct rhomboidal gap when closed; ischium subrectangular, 1.17 times longer than wide, 1.59 times longer than merus, with oblique setose ridge; merus subovate, 0.89 times longer than wide, with oblique setose ridge. Exopod slender, flattened, with long flagellum (Fig. 3B).

Right cheliped massive, longer than carapace; palm massive (Fig. 3C), surfaces rugose, dorsal surface with 2 oblique pectinate crests and 5 or 6 oblique granular ridges (Fig. 3D); outer surface smooth, slightly pitted, thin granular line on lower half commencing on pollex and extending posteriorly to carpal junction; inner surface sparsely granulated. Fingers massive, curved, with rounded spatulate tips, gaping when closed, outer surface with dense setose patch. Male dactylus with row of 12 prominent transverse ridges, proximal granules and scattered setae on dorsal surface; inner surface with proximal granular, setose patch. Cutting edges of dactylus and pollex with 4 subequal blunt teeth each (Fig. 3C).

P2-5, compressed, shorter than chelipeds. P2 and P5 short, P3 and P4 subequal. P2 and P3 propodi and carpi densely setose on anterior surface, P4-P5 propodi and carpi without dense setae. P2-P5 propodi posterior margins with one distal spine, ventral surface with inconspicuous oblique groove. P5 dactylus smooth, tip corneous, slightly curved, dorsal margin with six spines, ventral margin with three pairs of spines (Fig. 3E).

Male pleon bluntly triangular (AW/CW = 0.38), surface pitted, sutures with sparsely setose patches; lateral margins finely granulated, densely setose; telson 1.04 times as long as wide, 1.88 times as long as pleomere 6 (Fig. 3F).

G1 long, straight, distal part corneous, slender, flattened, slightly bent, lined by thick bristles, groove at base of tip extends along ventral surface to proximal portion of G1 (Fig. 7C, D).

Remarks. The specimen examined in the present study agrees with the description by De Man (1890De Man JG 1890. Carcinological studies in the Leyden Museum, No. 4. Notes from the Leyden Museum, 12: 49-126, pls. 3-6.) but differs in having 6 oblique granular ridges on dorsal surface of male cheliped propodus (vs. 7 or 8 in the holotype), and 4 occlusal teeth on pollex (vs. 3 in the holotype). Morphological comparison with other Indian species is provided in Tab. 1.

Geographical distribution. Nanosesarma batavicum was originally described from Batavia, Indonesia and later reported from Java, Malaysia, Singapore (Tweedie, 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.) and India (Trivedi et al., 2018Trivedi JN; Trivedi DJ; Vachhrajani KD and Ng PKL 2018. An annotated checklist of the marine brachyuran crabs (Crustacea: Decapoda: Brachyura) of India. Zootaxa, 4502 (1): 1-83. DOI: 10.11646/zootaxa.4502.1.1.
https://doi.org/10.11646/zootaxa.4502.1.... ). In India, it is known from Goa (present study), Kerala (Devi et al., 2015Devi LP; Joseph A and Khan AS 2015. Diversity of brachyuran crabs of Cochin backwaters, Kerala, India. p. 75-86. In: Venkataraman K and Sivaperuman C. (Eds.), Marine Faunal Diversity in India, Taxonomy, Ecology and Conservation. Elsevier, Amsterdam. DOI: 10.1016/B978-0-12-801948-1.00005-7.
https://doi.org/10.1016/B978-0-12-801948... ), Tamil Nadu (Varadharajan and Soundarapandian, 2014Varadharajan D and Soundarapandian P 2014. Crab biodiversity from Arukkattuthurai to Pasipattinam, southeast coast of India. Indian Journal of Geo-Marine Sciences, 43 (4): 676-698.) and Odisha (Dev Roy and Rath, 2017Dev Roy MK and Rath S 2017. An inventory of crustacean fauna from Odisha Coast, India. Journal of Environment and Sociobiology, 14 (1): 49-112.).

Nanosesarma minutum ( De Man, 1887De Man JG 1887. Uebersicht der indo-pacifischen Arten der Gattung Sesarma Say, nebst einer Kritik der von W. Hess und E. Nauck in den Jahren 1865 und 1880 beschriebenen Decapoden. Zoologische Jahrbücher, Abtheilung für Systematik, Geographie und Biologie der Thiere, 2: 639-722. https://biostor.org/reference/4033
https://biostor.org/reference/4033... )

(Figs. 1C, 4, 7E, F)

Sesarma minutaDe Man, 1887De Man JG 1887. Uebersicht der indo-pacifischen Arten der Gattung Sesarma Say, nebst einer Kritik der von W. Hess und E. Nauck in den Jahren 1865 und 1880 beschriebenen Decapoden. Zoologische Jahrbücher, Abtheilung für Systematik, Geographie und Biologie der Thiere, 2: 639-722. https://biostor.org/reference/4033
https://biostor.org/reference/4033... : 650.

Sesarma barbimana - Cano, 1889Cano G 1889. Viaggio della R. Corvetta Vettor Pisani attorno al globo: Crostacei Brachiuri ed Anomuri. Bollettino Società dei Naturalisti in Napoli, 3: 169-268. (nec De Man, 1888De Man JG 1888. Report on the podophthalmous Crustacea of the Mergui Archipelago, collected for the Trustees of the Indian Museum, Calcutta, by Dr. John Anderson, F.R.S., Superintendent of the Museum. Part III. Journal of the Linnean Society of London (Zoology), 22: 129-176. DOI: 10.1111/j.1096-3642.1887.tb00027.x.
https://doi.org/10.1111/j.1096-3642.1887... ): 245.

Sesarma (Sesarma) minutum - Rathbun, 1910Rathbun MJ 1910. The Danish Expedition to Siam 1899-1900. Brachyura. Memoires de I’Academic Royale des Sciences et des Lettres de Danemark, Copenhague, Série 7, Section des Sciences, part 5 (4): 303-367. : 327.

Sesarma (Sesarma) minuta - Tesch, 1917Tesch JJ 1917. Synopsis of the genera Sesarma, Metasesarma, Sarmatium and Clistocoeloma, with a key to the determination of the Indo-Pacific species. Zoologische Mededelingen, 3 (2-3): 127-260. DOI: 10.5962/bhl.title.10640.
https://doi.org/10.5962/bhl.title.10640.... : 174. - Tweedie, 1936Tweedie MWF 1936. On the Crabs of the Family Grapsidae in the Collection of the Raffles Museum. Bulletin of the Raffles Museum, 12: 44-71.: 52. - Chhapgar, 1957Chhapgar F 1957. On the marine crabs (Decapoda: Brachyura) of Bombay State. Part II. Journal of Bombay Natural History Society, 54 (3): 503-549, 3 pls.: 522, pl. 16, figs. k-m.

Sesarma (Sesarma) gordoni - Shen, 1935Shen CJ 1935. On some new and rare crabs of the families Pinnotheridae, Grapsidae and Ocypodidae from China. Chinese Journal of Zoology, 1: 19-40.: 27, figs. 7A-D.

Nanosesarma minuta - Tweedie, 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.: 311.

Nanosesarma cf. minutum - Crosnier, 1965Crosnier A 1965. Crustacés Décapodes Grapsidae et Ocypodidae. Faune de Madagascar, 18: 1-143. https://decapoda.nhm.org/references/pdfpick.html?id=15075&pdfroot=https://decapoda.nhm.org/pdfs
https://decapoda.nhm.org/references/pdfp... : 70, text-figs. 89, 109-115, pl. 6, fig. 1.

Nanosesarma minutum - Serène and Soh, 1970Serène R and Soh CL 1970. New Indo-Pacific genera allied to Sesarma Say 1817 (Brachyura, Decapoda, Crustacea). Treubia, 27 (4): 387-416.: 393.

Material examined. 10 males (CL: 2.4-4.6 mm, CW: 3.1-5.9 mm), 7 females (CL: 2.6-4.9 mm, CW: 3.3-6.2 mm), LFSC.ZRC-186, India, Goa, Chapora Estuary (15°37'21"N, 73°44'45"E), coll. Mithila Bhat, 13 May 2016.

Diagnosis. Carapace quadrangular, 1.26 wider than long; lateral margins almost straight, gradually diverging posteriorly; dorsal surface, strongly rugose, slightly convex, covered with scattered pits and sparsely placed setae only on front, protogastric, mesogastric and branchial regions delimited by conspicuous depressions. External orbital tooth truncate and triangular, followed by sharp epibranchial tooth. Several oblique, low, setose granulated striations extending across branchial regions (Figs. 1C, 4A). Frontal margin bilobed, strongly declivous, thickly setose, at level of eyes, frontal lobes separated by shallow depression; 4 inconspicuous postfrontal lobes covered with setose patches, separated by longitudinal grooves. Ocular peduncle well-developed, slightly setose, cornea terminal (Fig. 4A).

Third maxillipeds with distinct rhomboidal gap when closed; ischium subrectangular, 1.38 ± 0.19 times longer than wide, 1.18 ± 0.10 times longer than merus, with oblique setose ridge; merus 1.01 ± 0.11 times longer than wide, with oblique setose ridge. Exopod slender, flattened, with long flagellum (Fig. 4B).

Male chelipeds subequal, massive, longer than carapace; palm massive, surfaces rugose, dorsal surface without oblique pectinated crest, 3 inconspicuous oblique granulated ridges; outer surface with densely setose patch extending anteriorly to proximal portion of fingers, pitted, prominent granular ridge on lower half commencing on pollex and extending posteriorly up to carpal junction, 4 rows of closely spaced granules above granular ridge; inner surface sparsely granulated. Fingers massive, curved, with rounded spatulate tips, gaping when closed. Cheliped dactylus of male short with proximal setose granular patch on dorsal surface, transverse ridges absent; inner and outer surfaces with proximal setose granular patch. Cutting edge of dactylus with large subdistal tooth, followed by 2 small median and 2 large proximal teeth, that of pollex with large subdistal tooth, followed by 2 small teeth, large median tooth and 3 or 4 small teeth (Fig. 4C).

Pereopods compressed, shorter than chelipeds. P2 and P5 short, P3 and P4 subequal. P4 and P5 meri flattened, anterior margin terminating in blunt angle followed by subdistal spine; postero-distal margin with minute distal tooth-shaped granules followed by one spinule. P2-P5 propodi and carpi with long bristles on anterior margins. Propodi about twice as long as wide, posterior margins with 2 distal spines and few long bristles. Dactyli smooth, tip corneous, slightly curved, with 4 slender subdistal spines (Fig. 4D).

Male pleon narrow (PW/CW = 0.40 ± 0.04), bluntly triangular, surface pitted; lateral margins finely granulated, densely setose; telson 1.17 times as long as wide, 2.00 times as long as pleomere 6 (Fig. 4E). Female pleon wide (AW/CW = 0.72 ± 0.10), rounded, pleomere 6 with rounded distal margin, margins densely setose; telson wider than long, almost completely sunken into distal margin of pleomere 6 (Fig. 4F).

G1 long, straight, corneous distal part curved, long scoop-shaped, flanked by stiff bristles, groove at base of tip extends along ventral surface to G1 base (Fig. 7E, F).

Remarks. The morphology of the present specimens agree with that reported by De Man (1887De Man JG 1887. Uebersicht der indo-pacifischen Arten der Gattung Sesarma Say, nebst einer Kritik der von W. Hess und E. Nauck in den Jahren 1865 und 1880 beschriebenen Decapoden. Zoologische Jahrbücher, Abtheilung für Systematik, Geographie und Biologie der Thiere, 2: 639-722. https://biostor.org/reference/4033
https://biostor.org/reference/4033... ), Rathbun (1910Rathbun MJ 1910. The Danish Expedition to Siam 1899-1900. Brachyura. Memoires de I’Academic Royale des Sciences et des Lettres de Danemark, Copenhague, Série 7, Section des Sciences, part 5 (4): 303-367. ), Tweedie (1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.), and Crosnier (1965Crosnier A 1965. Crustacés Décapodes Grapsidae et Ocypodidae. Faune de Madagascar, 18: 1-143. https://decapoda.nhm.org/references/pdfpick.html?id=15075&pdfroot=https://decapoda.nhm.org/pdfs
https://decapoda.nhm.org/references/pdfp... ). However, it differs in having the presence of stiff distal setae on the G1 tip, which was probably omitted in the earlier reports. Morphological comparison with other Indian congeneric species is provided in Tab. 1.

Distribution. Nanosesarma minutum was originally described from Edam Island near Jakarta, Indonesia and later reported from Malaysia, Singapore, Gulf of Thailand, South China Sea (Tweedie, 1936Tweedie MWF 1936. On the Crabs of the Family Grapsidae in the Collection of the Raffles Museum. Bulletin of the Raffles Museum, 12: 44-71., 1950Tweedie MWF 1950. Notes on grapsid crabs from the Raffles Museum. Bulletin of the Raffles Museum, 23: 310-316.), Madagascar (Crosnier, 1965Crosnier A 1965. Crustacés Décapodes Grapsidae et Ocypodidae. Faune de Madagascar, 18: 1-143. https://decapoda.nhm.org/references/pdfpick.html?id=15075&pdfroot=https://decapoda.nhm.org/pdfs
https://decapoda.nhm.org/references/pdfp... ), Tanzania (Hartnoll, 1975Hartnoll GR 1975. The Grapsidae and Ocypodidae (Decapoda: Brachyura) of Tanzania. Journal of Zoology, 177: 305-328. DOI: 10.1111/j.1469-7998.1975.tb02235.x.
https://doi.org/10.1111/j.1469-7998.1975... ), and India (Trivedi et al., 2018Trivedi JN; Trivedi DJ; Vachhrajani KD and Ng PKL 2018. An annotated checklist of the marine brachyuran crabs (Crustacea: Decapoda: Brachyura) of India. Zootaxa, 4502 (1): 1-83. DOI: 10.11646/zootaxa.4502.1.1.
https://doi.org/10.11646/zootaxa.4502.1.... ). In India, it is known from Gujarat (Saravanakumar et al., 2007Saravanakumar A; Serebiah JS; Thivakaran GA and Rajkumar M 2007. Benthic macrofaunal assemblage in the arid zone mangroves of Gulf of Kachchh-Gujarat. Journal of Ocean University of China, 6 (3): 303-309. DOI: 10.1007/s11802-007-0303-3.
https://doi.org/10.1007/s11802-007-0303-... ), Maharashtra (Pati et al., 2012Pati SK; Sahu KC; Swain D; Baliarsingh SK and Sharma RM 2012. Marine crabs (Decapoda: Anomura and Brachyura). p. 381-385. In: Director, Zoological Survey of India, Kolkata (Ed.), Fauna of Maharashtra, State Fauna Series, 20 (Part-2). Kolkata, India, Zoological Survey of India.), Goa (present study), and Tamil Nadu (Kathirvel and Gokul, 2010Kathirvel M and Gokul A 2010. Checklist of brachyuran crabs from the Gulf of Mannar Marine Biosphere Reserve. p. 1-45. In: Technical Bulletin. Vol. 4. Chennai, The Fisheries Technocrats Forum.).

Nanosesarma sarii Naderloo and Türkay, 2009Naderloo R and Türkay M 2009. A new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf. Journal of Natural History, 43 (47-48): 2911-2923. DOI: 10.1080/00222930903219996.
https://doi.org/10.1080/0022293090321999...

(Figs. 1D, 5, 7G, H)

Nanosesarma (Nanosesarma) minutum - Tirmizi and Ghani, 1996Tirmizi NM and Ghani N 1996. Marine fauna of Pakistan: 5: Crustacea: Brachyura, Brachyrhyncha, part 1: Xanthidae, Goneplacidae, Pinnotheridae, Ocypodidae, Grapsidae. Karachi, University of Karachi, Center of Excellence. 188p.: 159, fig. 61A-D [not Sesarma minutumDe Man, 1887De Man JG 1887. Uebersicht der indo-pacifischen Arten der Gattung Sesarma Say, nebst einer Kritik der von W. Hess und E. Nauck in den Jahren 1865 und 1880 beschriebenen Decapoden. Zoologische Jahrbücher, Abtheilung für Systematik, Geographie und Biologie der Thiere, 2: 639-722. https://biostor.org/reference/4033
https://biostor.org/reference/4033... ].

Nanosesarma minutum - Jones, 1986Jones DA 1986. A field guide to the sea shores of Kuwait and the Arabian Gulf. University of Kuwait. Poole, Blandford Press, 192p.: 160, pl. 46. [not Sesarma minutumDe Man, 1887De Man JG 1887. Uebersicht der indo-pacifischen Arten der Gattung Sesarma Say, nebst einer Kritik der von W. Hess und E. Nauck in den Jahren 1865 und 1880 beschriebenen Decapoden. Zoologische Jahrbücher, Abtheilung für Systematik, Geographie und Biologie der Thiere, 2: 639-722. https://biostor.org/reference/4033
https://biostor.org/reference/4033... ].

Nanosesarma sariiNaderloo and Türkay, 2009Naderloo R and Türkay M 2009. A new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf. Journal of Natural History, 43 (47-48): 2911-2923. DOI: 10.1080/00222930903219996.
https://doi.org/10.1080/0022293090321999... : 9212-9218, figs. 1A, B, 2, 3.

Material examined. 3 males (CL: 4.6-5.6 mm, CW: 5.4-6.6 mm), LFSC.ZRC-188, India, Gujarat, Shivrajpur (21°19’55”N 68°57’02”E), coll. Jigneshkumar Trivedi, 3 February 2016.

Diagnosis. Carapace quadrangular, 1.13-1.17 times wider than long, widest at the level of second anterolateral teeth, evenly convex, sparsely plumose; lateral margins slightly concave, slightly converging posteriorly, dorsal surface covered with setal tufts and sparsely placed short and thin plumose setae, well-defined gastric region contained by deep groove, cardiac region with shallow groove. External orbital tooth sharply triangular, followed by smaller, slightly pointed epibranchial tooth. Dorsal surface finely granulated, 2 transverse granulated ridges originating from lateral margin, almost parallel to posterolateral margin, first ridge emerging just after epibranchial tooth, extending towards central region of carapace, second ridge originating near end of lateral margin, terminating at posterolateral edge, further 2 less-prominent, short ridges present, one emerging almost from the V-shaped notch between the anterolateral teeth, moving subparallel to first prominent ridge, other below first prominent one, nearly parallel to it (Figs. 1D, 5A). Basal antennal article long (Fig. 5B), reaching to about half of second article, antennae flagellum short, reaching cornea.

Third maxillipeds with distinct rhomboidal gap when closed, ischium subrectangular, 1.37 times longer than merus, internal margin crenulated, with long setae; merus subovate 1.18 times longer than wide, with longitudinal furrow on outer surface, margins crenulated, internal margin with long setae. Exopod slender, with long flagellum (Fig. 5C).

Chelipeds subequal; palm with entire outer surface covered with dense setae above lower row of granules, extending anteriorly to midlength of fingers (Fig. 5D), 3 rows of granules, lowermost regularly granulated, extending to centre of pollex, middle one short, irregularly granulated, subparallel to lower one, uppermost short, irregularly granulated, upcurving, upper margin with crenulated longitudinal line, dorsal surface without oblique pectinate crest or granulated ridges. Dactylus (except tip) with dorsal surface completely tuberculated, densely set small tubercles on proximal part with 6 comparatively large granules, all covered by tufts of setae, cutting edge with small teeth. Pollex short, smooth, cutting edge with several small teeth and large prominent one medially, finger-tips spatulate (Fig. 5E).

Pereopods medium-sized, P2 and P5 short, P3 and P4 longest, anterior meral margins weakly crenulated, bearing pointed subdistal tooth, posterior margins crenulated, posterodistal lobe denticulate. Propodi usually longer, about twice as long as wide with oblique carina on posterior face, 2 rows of long setae along propodus on anterior and posterior margins, P2-P4 with small brown setae on anterior margin of propodus, setae prominent and dense on P2. Dactyli distinctly more than half as long as propodus, with 8-10 spines, in 2 rows on posterior margin, 2 or 3 spines on anterior margin of P5, female P5 without any spine on anterior margin (Fig. 5F).

Male pleon elongated, triangular, smooth, pleomere 6 almost twice as broad as long, telson markedly elongate, about 1.60 times as long as broad (Fig. 5G).

G1 long, nearly straight, corneous distal part curved outwards with long stiff setae, groove at proximal part, with terminal opening on lateral side (Fig. 7G-H).

Remarks. The specimens examined in the present study agree with the holotype description of N. sarii provided by Naderloo and Türkay (2009Naderloo R and Türkay M 2009. A new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf. Journal of Natural History, 43 (47-48): 2911-2923. DOI: 10.1080/00222930903219996.
https://doi.org/10.1080/0022293090321999... ). The morphological comparison of N. sarii with other species of Nanosesarma reported from India is provided in Tab. 1.

Distribution. Nanosesarma sarii is previously known from Persian Gulf, Gulf of Oman, and Pakistan (Naderloo and Türkay, 2009Naderloo R and Türkay M 2009. A new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf. Journal of Natural History, 43 (47-48): 2911-2923. DOI: 10.1080/00222930903219996.
https://doi.org/10.1080/0022293090321999... ). The present specimens represent the first record from India.

Nanosesarma jousseaumei ( Nobili, 1906Nobili G 1906. Diagnoses préliminaires de 34 espéces et varietés nouvelles, et de 2 genres nouveaux de Décapodes de la Mer Rouge. Bulletin du Muséum d’Histoire Naturelle, Paris, 1 er série, 6 (for 1905) 393-411. )

(Figs. 1E, 6, 7I, J)

Sesarma (Sesarma) jousseaumeiNobili, 1906Nobili G 1906. Diagnoses préliminaires de 34 espéces et varietés nouvelles, et de 2 genres nouveaux de Décapodes de la Mer Rouge. Bulletin du Muséum d’Histoire Naturelle, Paris, 1 er série, 6 (for 1905) 393-411.: 411. - Nobili, 1906: 323, pl. 8, fig. 9.

Sesarma (Sesarma) jousseaumei - Laurie, 1915Laurie RD 1915. Reports on the marine biology of the Sudanese Red Sea. XXI. On the Brachyura. Journal of the Linnean Society of London, 31: 407-475, figs. 401-405, pls. 442-445. DOI:10.1111/j.1096-3642.1915.tb00463.x
https://doi.org/10.1111/j.1096-3642.1915... : 416. - Guinot, 1976Guinot D 1976. Constitution de quelques groupes naturels chez les Crustacés Décapodes Brachyoures. I. La superfamille des Bellioidea et trois sous-familles de Xanthidae (Polydectinae Dana, Trichiinae de Haan, Actaeinae Alcock). Memoires du Muséum National D’Histoire Naturelle, Nouvelle Série: Série A, Zoologie, 97: 1-308, figs. 1-47, pls. I-XIX. http://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=PASCALGEODEBRGM7750313776
http://pascal-francis.inist.fr/vibad/ind... : 283.

Nanosesarma jousseaumei - Holthuis, 1977Holthuis LB 1977. The Grapsidae, Gecarcinidae and Palicidae (Crustacea: Decapoda: Brachyura) of the Red Sea. Israel Journal of Zoology, 26: 141-192. DOI: 10.1080/00212210.1977.10688447
https://doi.org/10.1080/00212210.1977.10... : 172-174. - Ng et al., 2008Ng PKL; Guinot D and Davie PJF 2008. Systema Brachyurorum, part I. An annotated checklist of extant brachyuran crabs of the world. Raffles Bulletin of Zoology, Supplement, 17: 1-286.: 221. - Poupin et al., 2018Poupin J; Cleva R; Bouchard JM; Dinhut V and Dumas J 2018. The crabs from Mayotte Island (Crustacea, Decapoda, Brachyura). Atoll Research Bulletin, 617: i-vi, 1-109, figs. 1-23. DOI: 10.5479/si.0077-5630.617.
https://doi.org/10.5479/si.0077-5630.617... : 71, fig. 19G.

Material examined. 5 males (CL: 2.71-4.82 mm, CW: 3.12-5.55 mm), 12 females (CL: 5.43-5.41 mm, CW: 4.08-6.24 mm), LFSC.ZRC-187, India, Gujarat, Shivrajpur (21°19’55”N 68°57’02”E), coll. Jigneshkumar Trivedi, 3 February, 2016.

Diagnosis. Carapace quadrangular, 1.1-1.15 times wider than long, lateral margins almost straight, converging posteriorly; dorsal surface smooth, covered with setal tufts and long setae sparsely set among shorter plumose setae, regions well defined, front slightly protruded, bilobed with a shallow depression, extending to gastric region, straight depression separating gastric and cardiac regions, cardiac region with 2 small elevations, separated from intestinal region by a shallow depression, weakly granulated oblique ridge on posterior surface of carapace, extending from lateral margin to posterior edge. External orbital tooth triangular, followed by small, blunt epibranchial tooth (Figs. 1E, 6A). Basal antennal article (Fig. 6b) long, reaching to base of flagellum.

Third maxilliped morphology identical to that of N. sarii; ischium 1.33 times longer than merus, internal margin crenulated, possess long setae, merus 1.26 times longer than wide, with crenulated longitudinal margins, internal margin with long setae. exopod slender, with long flagellum (Fig. 6C).

Chelipeds distinctly unequal, palm relatively large, dorsal surface without oblique pectinate crest or granulated ridges, outer surface bearing 3 rows of tubercles fully covered with dense setae extending anteriorly to proximal portion of fingers (Fig. 6D), lower one with small tubercles, extending to basal third length of pollex, middle one shortest, oblique, with relatively large tubercles, upper row of granules short, nearly parallel to median one. Upper margin with sparse tubercles, some tubercles present on upper part. Fingers shorter than palm, with a large gap in proximal half, dactylus straight, dorsal surface completely smooth, small proximal granules with a large distinct tubercle on outer surface, distal half of cutting edge with 6 or 7 low tubercles, distalmost larger, pollex cutting edge with large prominent tubercle in middle part, tips of fingers spatulated (Fig. 6E).

Pereopods medium-sized, all articles except dactylus, densely covered with short plumose setae, long bristles between them. Meral posterior margins with distinct tooth-shaped granules, posterodistal margin with spiniform teeth, proximal one largest. Carpal anterior and posterior margins with longitudinal line of small tubercles, P5 without such line on posterior surface of carpus. Propodi smooth, 1.5 times as long as wide, posterodistal end with 2 groups of 3 small spines. Dactylus ending in large spine; 6 spines in 2 rows along posterior margin (Fig. 6F).

Male pleon bluntly triangular, pleomere 6 about 3.5 times as broad as long, lateral margins gently converging distally, telson 0.97 times as long as wide, rounded distally (Fig. 6G). Female pleon large, round, pleomere 6 longer than others, telson small, inserted into pleomere 6 (Fig. 6H).

G1 long, straight, distal part long, gently bending outwards, covered with long setae, posterior surface concave, groove nearly straight, terminal opening in posterior apical part. Some plumose setae along lateral margin (Fig. 7I-J).

Remarks. The specimens examined in the present study agree with the descriptions and illustrations of N. jousseaumei and N. sarii as discussed in Naderloo and Türkay (2009Naderloo R and Türkay M 2009. A new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf. Journal of Natural History, 43 (47-48): 2911-2923. DOI: 10.1080/00222930903219996.
https://doi.org/10.1080/0022293090321999... ). The morphological comparison of N. jousseaumei with other species of Nanosesarma reported from India is provided in Tab. 1.

Distribution. Nanosesarma jousseaumei was originally described from Gulf of Aden (Nobili, 1906Nobili G 1906. Diagnoses préliminaires de 34 espéces et varietés nouvelles, et de 2 genres nouveaux de Décapodes de la Mer Rouge. Bulletin du Muséum d’Histoire Naturelle, Paris, 1 er série, 6 (for 1905) 393-411.), and later reported from Madagascar, Dar es Salaam, Persian Gulf (Naderloo and Türkay, 2009Naderloo R and Türkay M 2009. A new species of the genus Nanosesarma (Crustacea: Decapoda: Brachyura: Sesarmidae), and redescription of Nanosesarma jousseaumei (Nobili, 1906), including new records from the Persian Gulf. Journal of Natural History, 43 (47-48): 2911-2923. DOI: 10.1080/00222930903219996.
https://doi.org/10.1080/0022293090321999... ), Mayotte (Poupin et al., 2018Poupin J; Cleva R; Bouchard JM; Dinhut V and Dumas J 2018. The crabs from Mayotte Island (Crustacea, Decapoda, Brachyura). Atoll Research Bulletin, 617: i-vi, 1-109, figs. 1-23. DOI: 10.5479/si.0077-5630.617.
https://doi.org/10.5479/si.0077-5630.617... ), and India (Trivedi et al., 2018Trivedi JN; Trivedi DJ; Vachhrajani KD and Ng PKL 2018. An annotated checklist of the marine brachyuran crabs (Crustacea: Decapoda: Brachyura) of India. Zootaxa, 4502 (1): 1-83. DOI: 10.11646/zootaxa.4502.1.1.
https://doi.org/10.11646/zootaxa.4502.1.... ). In India, it is known only from Gujarat (Ghosh, 2004Ghosh SK 2004. Crustacea: Decapoda: Grapsidae. p. 207-210. In: Director Zoological Survey of India, Kolkata (Ed.), Fauna of Gujarat. Part 2. State Fauna Series. Vol. 8. Kolkata, India, Zoological Survey of India.; Dev Roy, 2013Dev Roy MK 2013. Diversity and distribution of marine brachyuran crab communities inhabiting West Coast of India. p. 147-169. In: K Venkataraman; C Sivaperuman and C Raghunathan (Eds.), Ecology and Conservation of Tropical Marine Faunal Communities Part 1. Berlin and Heidelberg, Springer. https://doi.org/10.1007/978-3-642-38200-0_10
https://doi.org/10.1007/978-3-642-38200-... ; present study).

Key to Nanosesarma species from India

Cheliped palm dorsal surface with pectinate crest ……………………….......................2

- Cheliped palm dorsal surface without pectinate crest……………...................................3

Cheliped palm dorsal surface with 2 oblique pectinate crests and 4 or 5 oblique granular ridges; dactylus dorsal surface with row of 13 or 14 tubercles......................N. andersoni

Chelipeds palm dorsal surface with 2 oblique pectinate crests and 5 or 6 oblique granular ridges; dactylus dorsal surface with row of 12 prominent transverse ridges………………………………………………………...……………..N. batavicum

Male cheliped palm dorsal surface with 3 oblique granulated ridges; dactylus dorsal surface with proximal granular patch…….…………………….…………….N. minutum

Male cheliped palm dorsal surface unarmed; dactylus dorsal surface either tuberculate or smooth…………………………..…………………………..………………………..4

4. Male chelipeds with thick setose patch on entire outer surface of palm extending up to midlength of fingers; dactylus dorsal surface completely tuberculated; telson about 1.60 times as long as wide.……………...........................................…………………..N. sarii

Male chelipeds with thick setose patch on entire outer surface of palm extending to proximal portion of fingers; dactylus dorsal surface completely smooth; telson about 0.97 times as long as wide…………...……………………………………….N. jousseaumei

ACKNOWLEDGEMENTS

The authors are grateful to Ms. Dhruva Trivedi for help in preparation of sketches of the specimens and to Ms. Mithila Bhat for meticulous collection of specimens from Goa coast.

REFERENCES

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