Checklist of the Porcellanidae ( Crustacea : Decapoda : Anomura ) of India

(1) Sankolli (1963a) assumed that Pachycheles sp. recorded from the Gulf of Mannar by Gravely (1927) probably belongs to his new species, Porcellana gravelei. Later, Haig (1978) established the genus Ancylocheles for the latter species. (2) The records of Porcellana ornatus by Gravely (1927) and Sankolli (1968) are referred to those of Enosteoides ornatus (Stimpson, 1858), not Petrolisthes ornatus (Paulson 1875). (3) Southwell (1906) firstly recorded this species as Porcellana quadrilobata from India. Porcellana quadrilobata now belongs to the genus Lissoporcellana Haig (1978) as the type species of the genus. Southwell (1909) also described Porcellana gaekwari from Gulf of Mannar, India, but it is now considered as a junior synonym of L. quadrilobata, which is a associate of sponges. (4) Sankarankutty (1963) reported this species as Petrolisthes ohshimai (Miyake 1937). This species is now considered as a junior synonym of Neopetrolisthes maculatus (H. Milne Edwards 1837). (5) Heller (1862) reported this species from the Nicobar Islands as Porcellana barbata. (6) Gravely (1927) and Sankarankutty (1963) reported/ misidentified this species as Porcellana serratifrons and Pisidia spinulifrons from Gulf of Mannar. (7) Gravely (1927) reported this species as Polyonyx tuberculosus from the Gulf of Mannar. (8) P. splendidus and P. hendersoni represented a distinct genus, but taxonomic revision was not undertaken (Werding, 2001). (9) Only single species was recognized worldwide. Although the year of the issue was printed as “1961,” there was a delay in publication and it was actually issued in October 1962 (Low and Ng 2012).


Introduction
The family Porcellanidae is distinguished from other anomuran families by a crab-shaped body with a flattened abdomen.This family includes 30 genera and about 280 species around the world, mainly known from tropical to temperate waters (Osawa and McLaughlin 2010).Species of Porcellanidae generally occur from shore to continental shelf edges (<200 m), being more common in the intertidal and shallow subtidal zones of rocky and coral reefs.The species living in intertidal areas occupy narrow spaces between rocks or dead coral blocks, or on muddy bottoms (Werding and Hiller 2004) whereas, sub-tidal species occasionally live in association with other invertebrates (Werding 1983;Hiller et al. 2004;Hiller et al. 2006;Osawa and Chan 2010).
The studies on the porcellanids in India have a long history, with the first local report by Heller (1862) from the Nicobar Islands.However, the porcellanid fauna in India has not been satisfactorily explored.Thus, the present initiative was taken to provide an updated checklist on porcellanids of Indian waters with the hope to further contribute to the knowledge on the diversity of this family.

Materials and Methods
The present checklist is compiled based on the published records of porcellanids from India between the years 1862 and 2013.Species names mentioned in the checklist follow Osawa and McLaughlin (2010).The list is arranged alphabetically by names of genera and species, with literature on distributional and ecological information.A map of India with the localities cited in the checklist is shown in as Figure 1.The published records from Indian waters include 30 species in 11 genera.In the checklist, species with the mark * have the distribution restricted to the Indian subcontinents (Hiller et al. 2010), ** indicates that the species are endemic to type locality.Species with numbers in parentheses refer to additional remarks referring to taxonomic changes (see Table 1).

Additional Remarks
Abstract: Although the porcellanid fauna of Indian waters has been studied for more than 150 years, diversity of this family remains underestimated.In order to complement the knowledge on the porcellanid fauna of India, an annotated checklist is herein provided on the basis of published literature.A total of 30 species belonging to 11 genera are currently known from Indian waters.The distribution ranges of two porcellanids Porcellanella haigae and Pseudoporcellanella manoliensis indicate that they are endemic, as they are, so far, known only from their type locality (Gulf of Mannar, Tamilnadu).The list is arranged alphabetically by genus and species with information on species' distribution and ecology.from India are those by Heller (1862Heller ( , 1865) (6 species), Henderson (1893) (5 species), Gravely (1927) (8 species), Sankolli (1963aSankolli ( , b, 1965Sankolli ( , 1968) (10 species) and Southwell (1906Southwell ( , 1909) (8 species) respectively.Recent studies on porcellanids of Indian waters reported 10 species from Goa (Hiller et al. 2010) and 4 species from Lakshadweep (Prakash et al. 2013).The published information on this family likely underestimates the biodiversity of the Indian Peninsula.The present checklist indicates that most of the species were collected from the intertidal area and extended up to the deeper waters of 180 m (see Table 1).Most porcellanids are associates of other invertebrates like corals, sponges, hydrozoans, anthozoans and ascidians etc.
From the biogeographical aspect a few species are endemic to the type localities.Two porcellanid species Porcellanella haigae and Pseudoporcellanella manoliensis as they are, so far, known only from the Gulf of Mannar, Tamilnadu (type locality) and there are certain endemics to Indian subcontinents such as P. loimicola, P. splendidus and Raphidopus indicus are considered to be endemic to the Indian subcontinents.Compared to the species, all genera are evenly distributed on east coast (Gulf of Mannar and Nicobar islands) and west coast (Gulf of Kutch and Okha) of India except Neopetrolisthes, Porcellanella and Pseudoporcellanella, which are restricted to the Gulf of Mannar only.Species richness is higher in the Gulf of Mannar (17 species) and it suggests that the same number of species or more may present from the other reef areas such as Andaman & Nicobar Island, Lakshadweep, Gulf of Kutch and Ratnagiri due to the presence of similar habitats (rocky intertidal and coral reefs).The Nicobar Islands considered as one of the richest coral biodiversity hotspots (Venkataraman et al. 2004), but Heller (1862Heller ( , 1865) ) only reported 6 species.A recent report on porcellanids from Goa (Hiller et al. 2010) included 10 species belonging to 6 genera collected from the rocky intertidal and sub-tidal shallow waters.Prakash et al. (2013) reported only 4 species of porcellanids under the genus Petrolisthes from Lakshadweep and the collection are confined to the rocky intertidal region.
Other crustaceans like brachyurans and parasitic isopods (Cymothoidae) have been widely studied and collected throughout the Indian waters (Dev Roy 2008;Trilles et al. 2011).Recent checklists on brachyurans from coral reefs and mangrove regions of India include 389 species, in which Andaman & Nicobar Islands holds a high diversity of 196 species followed by the Gulf of Mannar with 156 species, Lakshadweep with 107 species, Gujarat with 50 species and Goa with 17 species and it suggests that the diversity of true crabs is more in coral reefs compared to mangroves as far as Indian region is concerned (Dev Roy, 2008).The checklist on parasitic isopods of the family Cymothoidae includes 36 valid species throughout the Indian waters (Trilles et al. 2011).Hence, it is concluded that Porcellanidae has been quite explored and seems to the case for brachyurans and other crustaceans and in future it is necessary that more sampling is required because the diversity of procellanids in India is probably underestimated.

Figure 1 .
Figure 1.Map of India showing the localities cited in the records of porcellanids.
Bay of Bengal, Gulf of Thailand, through south China sea, Taiwan strait, Southern Japan and Australia.India: Goa, Gulf ofMannar, Ratnagiri (Maharastra)