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Journal of Threatened Taxa Building evidence for conservation globally www.threatenedtaxa.org ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print) Short Communication First record of two rare brachyuran crabs: Drachiella morum Alcock, 1896 and Quadrella maculosa Alcock, 1898 along the Tamil Nadu coast, India Chinnathambi Viswanathan, Sampath Goutham, Vijay Kumar Deepak Samuel, Pandian Krishnan, Ramachandran Purvaja & Ramachandran Ramesh 26 August 2019 | Vol. 11 | No. 10 | Pages: 14358–14362 DOI: 10.11609/jott.3076.11.10.14358-14362 For Focus, Scope, Aims, Policies, and Guidelines visit https://threatenedtaxa.org/index.php/JoTT/about/editorialPolicies#custom-0 For Article Submission Guidelines, visit https://threatenedtaxa.org/index.php/JoTT/about/submissions#onlineSubmissions For Policies against Scientific Misconduct, visit https://threatenedtaxa.org/index.php/JoTT/about/editorialPolicies#custom-2 For reprints, contact <[email protected]> The opinions expressed by the authors do not reflect the views of the Journal of Threatened Taxa, Wildlife Information Liaison Development Society, Zoo Outreach Organization, or any of the partners. 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Partner Member Threatened Taxa Journal of Threatened Taxa | www.threatenedtaxa.org | 26 August 2019 | 11(10): 14358–14362 First record of two rare brachyuran crabs: Drachiella morum Alcock, 1896 and Quadrella maculosa ISSN 0974-7907 (Online) Alcock, 1898 along the Tamil Nadu coast, India Short Communication Short ISSN 0974-7893 (Print) Chinnathambi Viswanathan 1 , Sampath Goutham 2 , Vijay Kumar Deepak Samuel 3 , PLATINUM Pandian Krishnan 4 , Ramachandran Purvaja 5 & Ramachandran Ramesh 6 OPEN ACCESS 1–6 National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Anna University Campus, Chennai, Tamil Nadu 600025, India. 1 [email protected], 2 [email protected], 3 [email protected], 4 [email protected] (corresponding author), 5 [email protected], 6 [email protected] Abstract: The present report describes the first record of two Leucosiidae (Ng et al. 2008). The family Trapeziidae brachyuran crabs, Drachiella morum Alcock, 1896 and Quadrella Miers, 1886 are known as obligate commensals of corals maculosa Alcock, 1898 along the coast of Tamil Nadu, India. The morphological characters of the specimens are described and throughout the Indo-Pacific and eastern Pacific regions discussed. Among the two crabs, Q. maculosa was previously recorded (Castro et al. 2004). Trapeziidae has 43 species belonging only in the Andaman & Nicobar Islands. to three subfamilies and seven genera (Davie & Türkay Keywords: Crab, Drachiella morum, morphological characters, 2009). Both Aethridae and Trapeziidae are least studied Quadrella maculosa. from Indian waters since only three species of aethrids and nine species of trapezids are known from India. Previously, aethrids were reported in 1896 and 1934 In recent years, biodiversity research has gained (Alcock, 1896; Chopra, 1934); thereafter, no additional significant momentum owing to the decline of flora and observation from the Indian coast has been made in the fauna worldwide. Reporting the occurrence of a rare scientific reports, whereas a few trapezids were reported species is, thus, very important in order to update the from Rameshwaram and Andaman Islands (Alcock 1898; country’s biodiversity database. The brachyuran crabs of Sankarankutty 1961, 1962, 1966; ZSI 2012). the family Aethridae Dana, 1851 is a small group with 37 In the present study, we report an Aethridae crab, species under seven genera worldwide (Davie & Fransen Drachiella morum and a Trapeziidae crab Quadrella 2015). Some members of the Aethridae (Actaeomorpha maculosa for the first time from Tamil Nadu, southeastern and Drachiella) have long been associated with the family coast of India. The former was previously recorded in DOI: https://doi.org/10.11609/jott.3076.11.10.14358-14362 | ZooBank: urn:lsid:zoobank.org:pub:C723677B-544A-4EB9-A01A-D0D635337ACB Editor: A. Biju Kumar, University of Kerala, Thiruvananthapuram, India. Date of publication: 26 August 2019 (online & print) Manuscript details: #3076 | Received 30 September 2016 | Final received 01 May 2019 | Finally accepted 31 July 2019 Citation: Viswanathan, C., S. Goutham, V.K.D. Samuel, P. Krishnan, R. Purvaja & R. Ramesh (2019). First record of two rare brachyuran crabs: Drachiella morum Alcock, 1896 and Quadrella maculosa Alcock, 1898 along the Tamil Nadu coast, India. Journal of Threatened Taxa 11(10):14358–14362. https://doi.org/10.11609/ jott.3076.11.10.14358-14362 Copyright: © Viswanathan et al. 2019. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use, reproduction, and distribution of this article in any medium by adequate credit to the author(s) and the source of publication. Funding: National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Chennai. Competing interests: The authors declare no competing interests. Acknowledgements: The study was undertaken as a part of the National Project on Mapping Ecologically Sensitive Areas (ESA) in India, supported by the Ministry of Environment, Forest and Climate Change, Government of India. The authors thank Dr. R. Soundararajan, Scientific Consultant, National Centre for Sustainable Coastal Management, Chennai for reviewing the manuscript. 14358 Record of two rare brachyuran crabs from Tamil Nadu coast Viswanathan et al. Odisha (Alcock 1896) and West Bengal (Chopra 1934) Oreophorus rugosus Yokoya 1933, not O. rugosus and the latter was reported only in the Andaman Islands Stimpson 1858; vide Takeda & Miyake (1970). (Alcock 1898; ZSI 2012). Type locality: Ganjam coast, India (Alcock 1896). Materials examined: MBRC/Reg No: D1-511, 07 Materials and Methods September 2015, 1 female, from trawl net hauled at During the field survey, one crab belonging to the a depth of 20–30 m, and landed at Chennai Kasimedu species, D. morum (female) from Kasimedu fishing fishing harbor, Bay of Bengal, Tamil Nadu, India, coll. harbour and two crab individuals belonging to the Goutham Sampath. species, Q. maculosa (male, female) from Kottivakkam Measurements: Carapace width 10.7mm; carapace fish landing centre of Tamil Nadu, southeastern coast of length 8.6mm (details in Table 1). India, were collected. The former was collected from a Description: Carapace broader than long, quite oval. trawl bycatch while the latter was collected from a gill The entire surface of the body and appendages are net. Species identification of the collected specimens closely covered with vesiculous granules. The carapace was made by following the descriptions of Alcock (1896, as a whole is segmented and isolated into regions from 1898) and Galil (1986). The collected specimens were a broad marginal ring by sculptured groves; a narrow deposited in the Marine Biological Regional Centre bridge alone connecting the front to the gastric regions. (MBRC), Zoological Survey of India (ZSI), Chennai. The segmented regions are elegantly isolated from each other by a) two obliquely-longitudinal channels Order Decapoda Latreille, 1802 that cut off the acutely triangular gastro-cardiac region Family Aethridae Dana, 1851 from the reniform branchial regions, and b) a transverse Genus Drachiella Guinot, in Serène & Soh, 1976 channel that cuts off the semi-oval intestinal region Drachiella morum Alcock, 1896 (Image 1) – the channels being all connected to the marginal Synonyms: Holotype. Actaeomorpha morum Alcock ring. The orbits are spherical and are entirely closed 1896: 172–173. pl. VIII, fig. 3; Ihle, 1918: 308. out from the antennulary fossettes, the infra-orbital Actaeomorpha morum Chopra 1934: 480–481; lobe being in close contact with the frontal lobes. Edmonson 1935: 20; Sakai 1937: 116, text-fig. 13, 1965: The basal antennal segment is fused with the infra- 35, pl. 15, fig. 3; Serene 1954: 458, pl. 7 and text-fig. 1,2; orbital lobe, but the antennal flagellum is distinct. Zarenkov 1969: 16, fig. 1(1); Takeda & Miyake 1970: 218. The chelipeds and legs are closely crowded with large “Aff. Oreophorus” morum, Guinot 1966: 757. granules. The carpus and propodus are covered with spiniform granules. Merus in the last pair of legs is also spiniform on the posterior region. Colour: Orange brown colour in fresh specimen. Distribution: India: Odisha and West Bengal (Alcock 1896), Tamil Nadu, India (present study); Japan (Yokoya 1933): Misaki (Sakai 1937), Sagami Bay (Sakai 1965), Kii Nagashima and Tosa Bay (Sakai 1976); East China Sea (Takeda & Miyake 1970a); South China Sea (Dai & Yang 1991); Vietnam, Thailand and Philippines (Serène & Vadon 1981; Chen 1989). Remarks: Drachiella morum was first reported as Actaeomorpha morum by Alcock (1896). Later, Guinot (1966) removed the species from