Halaelurus quagga ( Alcock 1899 )

Akhilesh, K. V., Bineesh, K. K., Shanis, C. P. R., Human, B. A. & Ganga, U., 2011, Rediscovery and description of the quagga shark, Halaelurus quagga (Alcock, 1899) (Chondrichthyes: Scyliorhinidae) from the southwest coast of India, Zootaxa 2781 (1), pp. 40-48 : 42-46

publication ID	https://doi.org/ 10.11646/zootaxa.2781.1.3
persistent identifier	https://treatment.plazi.org/id/0063A152-CE53-FF9F-FF49-3E1EFC490184
treatment provided by	Felipe
scientific name	Halaelurus quagga ( Alcock 1899 )
status

Treatment

Halaelurus quagga ( Alcock 1899) View in CoL

Quagga catshark

Figs 2–7 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 ; Table 1.

Scyllium quagga Alcock 1899 View in CoL . A descriptive catalogue of the Indian deep-sea fishes in the Indian Museum. Calcutta. p.17

Holotype. ZSI F751/ 1. 273 mm TL, adult male, Laccadive Sea (Arabian Sea), off Malabar coast, 8°23'N – 76°28'E, depth 186.5 m collected by RIMS Investigator . GoogleMaps

Other material. 4 specimens: GA.1.6.2.1, female, 360 mm TL, off Quilon (8º55’N 76º30'E), Arabian Sea, 90 m depth, collected by C.P. Rajool Shanis on 8 February 2010 from deepsea shrimp trawls landed at Sakthikulangara Fisheries Harbour; CMFRI /PFD/S/5.5, gravid female, 368 mm TL, off Quilon (9º04’N 74º32E), Arabian Sea , 180 m depth, collected by K. V. Akhilesh & K.K. Bineesh on 11 August 2010 from demersal trawls landed at Cochin Fisheries Harbour ; CMFRI /PFD/S/5.6, male, 309 mm TL, off Quilon , Arabian Sea , 220–280? m depth, collected by K. V. Akhilesh on 20 December 2010 from deepsea shrimp trawl bycatch landed at Sakthikulangara Fisheries Harbour; CMFRI /PFD/S/5.7, male, 315 mm TL, collection data as for CMFRI/PFD/S/5.6 GoogleMaps .

Diagnosis. A small shark with numerous (>20) vertical stripes on the body without dark spots, snout tip knoblike but not prominently upturned. Eyes in adults 12–13 times in distance from snout to first dorsal origin. Anterior nasal flaps sub triangular. Gills dorsolaterally placed and elevated above the mouth level. First dorsal-fin origin about opposite pelvic-fin insertion. Light brown above with pale ventral side, dark brown cross bands on the body.

Description. Proportional measurements in percentage of total length are given ( Table 1). A small shark, body slender, tapering posteriorly, trunk length 0.93–1.14 times head length (HL), head short, depressed, head length 20.53–21.75% TL, 1.19–1.72 in pectoral-pelvic space; small snout, snout length 3.31–3.59 in HL, eyes small placed dorsolaterally, eye length 5.75–6.59 in HL, small spiracles, spiracle length 0.97–1.14% TL, elevated and dorsolaterally placed gills, first four sub-equal gill slits, followed by the smallest, mouth relatively large, mouth width 8.05–9.09% TL, length 4.93–5.13 % TL, preoral length 4.44–5.04% TL; labial furrows short, lower labial furrows 1.95–2.48 in eye length; pre-dorsal length 2.19–2.29 in TL, 43.71–45.68 % TL. Anterior nasal flaps large and triangular. First dorsal-fin origin about opposite to pelvic-fin insertion, and smaller than second dorsal fin. First dorsal-fin length 8.16–8.58% TL, first dorsal-fin base length 6.08–6.47% TL, second dorsal-fin length 8.16–8.77% of TL. Second dorsal-fin base 6.12–7.12% TL, inter-dorsal space 13.15–15.66% TL. Anal fin larger than seconddorsal fin, anal-caudal space 10.90–12.38% TL, dorsal-caudal space 7.99–8.67% TL. Lower caudal fin lobe poorly developed but distinct.

Claspers slender and tapering, hypopyle with a distinct knob and hooks. Eggcase medium sized with long coiled tendrils. Egg case length (ECL) 38.4–40.24 mm, egg case height 19.6–21.25 % ECL, anterior case width 32.65–34% ECL, posterior border width 5.60–6.65% ECL, anterior border width 17.51–18.61% ECL, posterior case width 44.42–46.25% ECL.

Colour. Dorsal surface light brown with numerous very dark brown bands, with six bands from the pectoral insertion to first dorsal origin. No dark spots on the body. Posterior margin of pectoral, pelvic and anal fins whitish. Inter-dorsal space with three bands, middle one largest with a paler area in the centre. First and second dorsal fins with bands continued from the body, a lighter area in the centre of dorsal fins. Ventral surfaces whitish.

Size & biology. Attains a maximum size of 370 mm TL. Female of 368 mm TL was gravid and contained eight egg cases, four in each uterus. Feeds on shrimps.

Distribution & habitat. Western Indian Ocean: India (Arabian Sea) and Somalia (Indian Ocean coast), offshore on continental slope, 54–186 m ( Springer & D’Aubrey, 1972; Compagno et al., 2005). Collection of H. quagga from deepsea shrimp trawlers indicate that the species could have a wider depth distribution, possibly down to 280 m.

Remarks. This is the first record of H. quagga specimens from India since its description by Alcock in 1899, which was based on a single male specimen collected from the southwest coast, off Malabar ( Compagno, 1984). Norman (1939) reported a single male specimen captured from the Gulf of Aden ( Somalia), although Springer & D’Aubrey (1972) and Springer (1979) re-identified that specimen as H. boesemani .

However, in 1964, the RV Anton Bruun collected four male specimens (one juvenile 80 mm TL and three mature specimens 333, 342, 351 mm TL) from the Indian Ocean coast of Somalia from 59–70 m depths that were referable to H. quagga ( Springer & D’Aubrey, 1972; Springer 1979). These specimens had been deposited in the USNM, but presumably had not been assigned lot numbers at the time of those publications. Some of those specimens are referable to lots USNM 221466 (80 mm TL), and USNM 221467 (351 mm TL) (details unavailable for the other specimens).

The recent specimens collected from India increase the known number of H. quagga specimens to nine. According to the IUCN list of threatened species, this species is assessed as Data Deficient based on the limited records ( Cronin, 2007).

Similar species from the Western Indian Ocean are two southern African endemics, H. lineatus and H. natalensis , which have a snout tip that is upturned ( Compagno, 1984; White et al., 2007). This character differentiates H. quagga from the South African endemics, which doesn’t have a prominent upturned snout tip. Moreover, H. natalensis has only about 10 dark saddles and H. lineatus has other body markings with more than 20 saddles. Halaelurus lineatus is superficially similar to H. quagga in body markings and colour pattern, but the former has a mouth width 7% or less of TL compared to 8–9% TL in H. quagga ( Springer & D’Aubrey, 1972; White et al., 2007). Halaelurus quagga differs from H. boesemani in its colour pattern and morphometrics: mouth length 4.9–5.1% TL vs 2.2% TL and 2.9–3.8 vs 3.7 in mouth width. Bass et al., 1975 and Bass (1986) states that H. lineatus has up to 16 egg cases and H. natalensis has 6– 11 egg cases per female. In the present study, eight egg cases were collected from a single H. quagga specimen (368 mm TL).

DNA barcodes were generated for H. quagga for the first time. Usage of DNA barcodes to accurately discriminate species of chondrichthyans have only recently been used. A DNA barcoding study is currently underway using the sequence data of H. quagga and other chondrichthyan species from Indian waters (Bineesh et al., in prep.).There are no recent taxonomic studies on the chondrichthyan fauna in Indian waters. Recent chondrichthyan taxonomic studies around the world (e.g. Indonesia and Australia) have resulted in many new species and increased taxonomic resolution of species complexes ( White et al. 2007; Last et al. 2008), which suggests that a systematic study of the chondrichthyan diversity in Indian waters would likely identify a greater diversity of fauna. Although more than 150 species of chondrichthyans are reported to occur in Indian waters, representative specimens in ichthyological collections are very few and insufficient for detailed taxonomic studies. Many species reported have a questionable status of occurrence that needs to be resolved. India has a wealth of biodiversity, and documentation of its flora and fauna is essential. Without properly documenting the biodiversity of India, there is little scope for effective conservation and management of vulnerable and exploited species.