Indian Journal of Geo Marine Sciences Vol. 47 (04), April, 2018, pp. 798-801 First record of the shrimp-associate gobiid fish Cryptocentrus filifer (Valenciennes) from the Indian coast Dipanjan Ray1, Anil Mohapatra1,2*& Helen K. Larson2 1Marine Aquarium and Regional Centre, Zoological Survey of India, Digha, India 721 428 2Estuarine Biology Regional Centre, Zoological Survey of India, Gopalpur-on-Sea, Ganjam, Odisha, India-761002. 3Museum and Art Gallery of the Northern Territory, P.O. Box 4646, Darwin, Northern Territory 0801, Australia; Museum of Tropical Queensland, 102 Flinders Street, Townsville, Queensland 4810, Australia *[E.Mail: [email protected]] Received 28 July 2016; revised 23 November 2016 The shrimp-associate gobiid Cryptocentrus filifer (Valenciennes, 1837) is reported for the first time from Indian coastal waters, with four specimens along with its morphometrics. Cryptocentrus is discussed and compared with closely related Indian shrimp-associate gobiids and the sexual dimorphism of the species is described. [Keywords: Bay of Bengal, Cryptocentrus, Myersina, West Bengal, New record] Introduction Indian waters. Four specimens of Cryptocentrus The family Gobiidae is one of the largest groups of filifer were collected from Shankarpur fishing harbor, teleost fishes in the world with at least 1630 species in West Bengal, India, during a routine survey for fish 248 genera1 and with many undescribed species; most collection. This present study describes their meristics of these are Old World coral reef-associates. In the and morphometrics and discusses the status of Indo-Pacific, coral reef gobiids represent 35% of total shrimp-associate gobiids of the Indian coast. fishes and 20 % of species diversity2. Gobiids are also The genus Cryptocentrus Valenciennes so far present in rivers, estuaries, near shore and in fresh comprises 35 valid species worldwide and all are water communities on islands they are particularly distributed within the Indo-Pacific region. The genus diverse3-4. is characterized by having eyes placed high on the In the Indo-Pacific the genus Cryptocentrus is one side of the head with interorbital narrower than eye; of the 12 “shrimp gobies” presently recognized head pores present; a transverse papilla pattern with (Amblyeleotris, Cryptocentrus, Cryptocentroides, two parallel papilla rows on chin and lower horizontal Ctenogobiops, Flabelligobius, Lotilia, Mahidolia, papilla row extending backward from second vertical Myersina, Psilogobius, Stonogobiops, row; pelvic fins connected, forming a disc; dorsal rays Tomiyamichthys, Vanderhorstia); species of these I, 9-12; anal rays I, 9-11; first dorsal fin origin behind genera live commensally with alpheid shrimps (genus pelvic fin insertion; gill opening extending to usually Alpheus)4-5. Most species of these genera interact with below posterior pre-opercular margin; scales usually shrimps either facultatively or obligately; the basic cycloid (if ctenoid then dorsal and anal rays I, 9-10 mechanism of the association is the shrimp and gill opening narrow); jaws long, usually reaching constructing and maintaining a burrow which the to or beyond end of eye7. gobies use as a safe breeding and resting site while also acting as sentinels, being present near the burrow Materials and Methods entrance, warning the shrimp of approaching danger During a survey around January 2013 at the Digha through actions detected by the shrimp’s antennae coast of India, four unusual gobiids were collected (one antenna always in contact with the fish). from Shankarpur fishing harbor of West Bengal. Cryptocentrus filifer (Valenciennes, 1837)6 is Fishermen of this harbor generally use trawl nets for among those species obligately associated with fishing in the northern part of Bay of Bengal. After Alpheus shrimp5 and for first time we report it from collection, photographs were taken (Fig. 1) and RAY et al.: FIRST RECORD OF CRYPTOCENTRUS FILIFER FROM THE INDIAN COAST 799 subsequently identified (by HKL) as Cryptocentrus filifer. Methods of counting and measuring specimens follow Winterbottom8. Morphometric measurements of the fishes were taken by digital caliper with resolution of 0.1 mm and data and ratios presented in Table 1. Sensory pores and papillae were observed by Leica ez4 microscope; vertebral data taken from a digital X-ray. Abbreviation SL and HL represents Fig. 1 — Cryptocentrus filifer (Valenciennes, 1837), 83.6 mm SL standard length and head length respectively. The four specimens (70.5-84.3 mm SL) were preserved in 10% Table 1 — Morphometrics of Cryptocentrus filifer formaldehyde and housed at the Marine Aquarium (Valenciennes, 1837) and Regional Centre, Zoological Survey of India, In percentage of SL Digha; West Bengal, India (registration number Body depth 15.2-16.81 MARC/ZSI/3468). Head length 30.87-31.45 Eye diameter 6.14-6.56 Results Interorbital space 2.97-3.29 Cryptocentrus filifer (Valenciennes, 1837): Silt Maxilla length 15.98-13.75 Snout length 6.10-6.75 shrimp goby Body depth 7.76-8.88 Description Sub orbital depth 4.94-5.06 Dorsal fin with 6+1 spine and 10 rays; anal fin Head length after eye 17.13-17.4 with 1spine and 9 rays; pectoral fin with 17 rays; Predorsal 35.04-35.40 pelvic fin with 1 spine and 5 rays and caudal fin with Preanal 61.72-62.24 Preventral 31.03-31.25 17 segmented rays. Body small, moderately elongate Prepectoral 29.12-29.69 and compressed (Fig 1.); the different body Pectoral fin length 18.40-20.09 measurements with the percentage of standard length Ventral fin length 21.26-29.90 (SL) and head length (HL) are given in Table–1. Caudal fin length 29.56-30.07 Anterior nostril short and tubular, posterior nostril 1st dorsal spine 16.31-22.59 opens in a pore; cheek not bulbous; mouth large, 2nd dorsal spine 25.43-25.43 rd oblique, lower jaw slightly projecting, maxilla 3 dorsal spine 18.59-26.25 4th dorsal spine 17.17-23.98 reaching well behind eye. Upper jaw with outer row th of curved and sharp caniniform teeth, inner teeth in 5- 5 dorsal spine 15.51-23.69 6th dorsal spine 9.13-10 6 rows of irregular small curved teeth across front and 1st soft dorsal rays 14.54-16.02 2-3 rows at side of the jaw; lower jaw with outer row Caudal peduncle depth 7.93-8.11 of conical curved teeth followed by 5-6 inner rows of Caudal peduncle length 14.86-15.90 pointed teeth acrossfront and 2-3 rows on side; tongue In percentage of HL smooth and rounded. Gill membranes fused to Eye diameter 19.88-20.86 isthmus in ventral midline but not forming a free fold Interorbital space 9.46-10.68 across isthmus; 12 gill rakers on lower limb of first Snout length 19.76-20.47 gill arch. Only cycloid scales present on body except Maxilla length 50.93-44.40 for scale less nape, head and pectoral fin base. Suborbital depth 16.02-16.15 Head length after eye 54.46-56.39 Sensory papilla pattern on cheek in five transverse rows radiating from eye and not extending below fourth soft ray of second dorsal; in one specimen longitudinal row (Fig 2); preopercular sensory canal (72.6 mm; female) first five dorsal spines not with two pores; number of infraorbital canal pore, elongate, third longest, 18.59 % SL, first dorsal fin postorbital pore, posterior interorbital pore, posterior when depressed just reaching second dorsal fin origin. nasal pore and anterior interorbital pore is 1 on each First ray of second dorsal fin shorter than others, its side of head. Total vertebrae 26[10+16]. In three length 14.45-16.22 % in SL, longest soft rays specimens the first five dorsal spines are elongate, 21.85-22.50 % in SL. Anal fin origin below third fin with third spine longest, 23.69 % in SL, spinous part ray of second dorsal fin. Origin of pectoral fin just of first dorsal fin when depressed reaching to base of above pelvic fin base. Pectoral fin length 18.40-19.59. 800 INDIAN J. MAR. SCI. VOL. 47, NO. 04, APRIL 2018 crocatus and C. pretoriusi from Cryptocentrus and placed the three species in the genus Myersina. A search of literature shows that this species is regularly placed in either Cryptocentrus (most recently by Matsui et al. 19) or Myersina (most recently by Allen & Erdmann15). Work underway by D. Hoese and K. Shibukawa indicates that C. filifer does not fit well within either genus (D.F. Hoese pers. comm.) and its Fig. 2 — Lateral view of head of Cryptocentrusfilifer (84.3 mm SL) status remains to be resolved. Hence, the older showing sensory pores (red dots) and main rows of papillae (black dots). nomenclature is retained here. Pelvic fins fused forming disc; origin of pelvic fin just A comprehensive phylogenetic study of Indo- below dorsal fin origin; in three specimens pelvic fin Pacific shrimp-associate gobies remains to be carried tip reaching anus, its length 29.90 % of SL; in a out. Several recent genetic analyses of gobioid (72.6 mm)specimen the pelvic fin does not reach relationships have not included shrimp-associates anus, its length 21.26 % of SL. Caudal peduncle depth other than Amblyeleotris and Ctenogobiops (e.g. 7.93-8.11 % in SL, caudal peduncle length Agorreta and Rubeer20; Thacker21). However, Thacker 14.86-15.90 % in SL; caudal fin pointed. and Roje4 analysed seven genera of shrimp-gobies but Colour: Body creamy white with very small black excluded six; the shrimp-associates fell out into two dots dorsally and five diffuse, broad dark bars, darker clades. Shibukawa et al.21 reviewed the genus Lotilia dorsally and paler ventrally, first bar beginning from and provided some discussion of the group, pointing first dorsal fin base, second from just anterior to out the poor state of understanding of relationships origin of second dorsal fin, third from middle of among shrimp-gobies.