Torquigener heemstrai, Gaonkar & Mohammed & Ribin & Kumar & Thomas & Saini, 2024

Gaonkar, Prachi, Mohammed, Imad, Ribin, Mohammed, Kumar, D Chetan, Thomas, Pallavi A & Saini, Ruchi, 2024, A New Pufferfish, Torquigener heemstrai from South Africa (Acanthopterygii, Tetraodontiformes, Tetraodontidae), Bulletin of the National Museum of Nature and Science. Series A, Zoology 50 (2), pp. 81-85 : 82-83

Torquigener heemstrai n. sp.

( Figs. 1–3 )

urn:lsid:zoobank.org:act:C4597A99-A986-4AB4-996E-7E6D5EEDB084

Material examined. Holotype: SAIAB 60948 , 94.8 mm SL, Tugela Bank (29°13′S, 31°29′E), KwaZulu-Natal, South Africa, 30 m depth, October 1999 . Paratypes: SAIAB 40751 , 90.7 mm SL, same locality as holotype, 40 m depth, 16 Aug. 1991 ; SAIAB 60949 , 3 specimens, 74.7–87.0 mm SL, same locality as holotype, 26 Sept. 1999 .

Diagnosis. A species of Torquigener with the following combination of characters: dorsal-fin rays 8 (9); anal-fin rays 7; pectoral-fin rays 14; prebranchial margin with 14 (11–12) long spinules; 12 (14) spinules on back between just behind mid-dorsal branches of lateral line; dorsal half of body blackish brown with many short white lines, an irregular white line running along ventrolateral part of body just above a skin fold from dorsal end of gill opening to caudal peduncle, and ventral part of body white.

Description. Body moderately elongate, rounded dorsally and flattened ventrally in cross section, tapering posteriorly to laterally compressed caudal peduncle. A longitudinal skin fold extending on ventrolateral corner of body from just behind pectoral fin to ventral part of caudal-fin base. Mouth small, terminal; lips thin, covered with many short papillae; chin prominent. Nasal organ a short, erect papilla well before eye, with two well-separated openings. Eye large, 4.8 (4.1–4.6) in head length, elliptical, and dorsally adnate, ventral rim at level slightly above upper jaw. Gill opening a slightly curved slit just anterior to pectoral-fin base.

Dorsal fin slightly rounded, its origin just above anal-fin origin; anal fin slightly rounded, smaller than dorsal fin; pectoral fin rounded, 1st pectoral-fin ray rudimentary and nubbin-like, dorsal end of pectoral-fin base at level slightly below mouth; caudal fin slightly rounded.

Two lateral lines on head and side of body ( Fig. 2 ). The dorsalmost lateral line encircles the eye, with a preopercular branch terminating at level of dorsal end of pectoral-fin base and a posteriorly directed branch coursing along the mid-lateral side of body from just behind ventroposterior part of eye to caudal-fin base, with a dorsally directed branch just above pectoral fin almost meeting in midline with its counterpart from the other side of the body. A short transverse element of lateral line in front of nasal organ almost meeting in midline with its counterpart from the other side of the snout; another short branch running ventrally on lower jaw. The ventral lateral line originates at midpoint between pectoral and anal fins and courses along the ventrolateral edge of body to caudal-fin base.

Two-rooted spinules present on head and body, extending on dorsal surface from nasal organs to the region anterior to dorsal-fin origin ( Fig. 3 ); two-rooted spinules also densely developed on ventral surface from just behind chin to vent.

Proportional measurements expressed as percentage of SL. Head length 34.9 (32.2–38.3), snout length 14.6 (13.8–14.7), snout to dorsal-fin origin 69.2 (67.6–71.0), snout to anal-fin origin 67.3 (67.7–71.8), body width at pectoral-fin base 27.8 (25.7–27.6), body depth at anal-fin origin19.9 (16.4–21.1), depth of caudal peduncle 8.4 (8.2– 10.0), length of caudal peduncle 28.6 (24.9–27.8), gill-opening length 11.1 (7.9–12.1), eye diameter 6.6 (7.1–9.4), bony interorbital width 6.2 (5.4–6.7), snout to anterior edge of nasal organ 8.1 (7.0–11.1), posterior edge of nasal organ to anterior edge of eye 6.1 (4.9–6.3), length of dorsal-fin base 6.4 (6.1– 8.7), length of anal-fin base 5.1 (3.9–5.5), longest dorsal-fin ray 15.6 (17.7–21.0), longest anal-fin ray 12.9 (14.4–16.3), longest pectoral-fin ray 18.1 (16.9–20.0), caudal-fin length 24.7 (25.4–29.2).

Color of freshly dead specimens ( Fig. 1 ). Dorsal half of head and body blackish brown covered by many short white lines; ventral half of head and body white; an irregular white line running along ventrolateral part of body just above a skin fold from dorsal end of gill opening to caudal peduncle; many small irregular blackish brown spots along a skin fold; edge of eye dark yellow; dorsal, anal and pectoral fins transparent with slightly grayish rays; dark brown smudge on dorsal part of pectoral-fin base; caudal fin transparent with dark gray rays.

Distribution. Torquigener heemstrai n. sp. is currently known only from the type locality.

Etymology. The specific name, heemstrai , refers to the late Phillip C. Heemstra in honor of his great contribution to ichthyology in South Africa.

Remarks. The new pufferfish is classified in the genus Torquigener by having the following combination of characters: eye dorsally adnate only; chin well developed; two openings on nasal organ; ventrolateral skin fold extending behind pectoral fin to caudal-fin base. The revision of 12 Australian species of Torquigener ( Hardy, 1983a) was followed by descriptions of additional eight new species from various regions of the Indo-Pacific ( Hardy, 1983a, b, 1984, 1989; Hardy and Randall 1983; Matsuura, 2014). Torquigener heemstrai brings the total number of species of Torquigener to 21.

Major characters distinguishing Torquigener heemstrai n. sp. from all other species of the genus are provided in the Diagnosis above. The most helpful characters in separating the new species from the other species of Torquigener are coloration of the head and body: no solid, dark, longitudinal stripe nor longitudinal rows of dark spots on the mid-side of body from behind pectoral fin to caudal-fin base; no vertical markings on cheek; dorsal half of head and body blackish brown covered with many short white lines; and ventral half of head and body white.

Figures

Fig. 1. Holotype of Torquigener heemstrai n. sp., SAIAB 60948, 94.8mm SL, Tugela Bank (29°13′S, 31°29′E), KwaZulu-Natal, South Africa, 30m depth, October 1999, photo by P. C. Heemstra.

Fig. 2. Schematic illustration of lateral line system of Torquigener heemstrai n. sp.

Fig. 3. X-ray CT scanning photographs showing the two-rooted spinules of the holotype of Torquigener heemstrai n. sp. Top, lateral view; bottom, dorsal view.