Austrobatrachus iselesele, Greenfield, David W., 2012

Greenfield, David W., 2012, Austrobatrachus iselesele, a new toadfish species from South Africa (Teleostei: Batrachoididae), Zootaxa 3400, pp. 58-63 : 59-63

Austrobatrachus iselesele n. sp.

Zulu toadfish

( Figs. 1–5 )

Holotype. SAIAB 99219, 212.4 mm, Park Rynie, KwaZulu-Natal, South Africa, 30°19’47”S, 30°46’04”E, 50 m, reef, gaff, A. Connell, 15 March 2011.

Paratypes. SAIAB 99218, 181.4 mm, Park Rynie, KwaZulu-Natal, South Africa, 30°19’47”S, 30°19’47”E, 49 m, reef, gaff, A. Connell, 26 April 2011. SAIAB 98664, 192.1 mm, Park Rynie, KwaZulu-Natal, South Africa, 30°17’S, 30°50’E, 49 m, reef, gaff, A. Connell, 19 February 2011.

Other material examined. Austrobatrachus foedus - SAIAB 26224, SAIAB 12748, SAIAB 12744.

Diagnosis. A species with a foramen at the top of the pectoral-fin axil, no tentacles over the eye, and fine lines and ridges on the snout, interorbital area, and on top of the head posterior to the orbit (true for the genus). Body with distinct black spots on sides and pectoral-fin base. Snout 5.0 % SL or greater, eye into caudal-peduncle depth 0.86–1.10 times.

Description. Dorsal-fin elements III-21 (21–23); anal-fin rays 18 (15–18); pectoral-fin rays 21 (20–21); head length 36.5 (32.5–37.5, 34.8); head width 34.6 (31.7–35.3, 33.9); head depth 20.9 (20.9–22.7, 21.8); bony interorbital width 4.7 (4.7–4.8, 4.7); fleshy interorbital width 5.8 (5.6–6.2, 5.9); orbit diameter 7.7 (7.7–10.1, 8.8); snout length 6.1 (5.1–6.1, 5.6); upper jaw length 17.1 (17.1–18.6, 18.0); mouth width at rictus 19.0 (19.0–21.3, 20.1); first predorsal-fin distance 34.6 (34.6–35.3, 34.9); second predorsal-fin distance 44.4 (44.4–47.5, 45.9); preanal-fin distance 59.2 (59.2–60.2, 59.6); greatest body depth 20.0 (20.0–22.3, 21.3); caudal-peduncle depth 8.3 (8.3–8.7, 8.5); caudal-peduncle length 9.1 (8.3–9.1, 8.8); first dorsal-fin base length 7.7 (7.7–9.1, 8.6); second dorsal-fin base length 46.9 (46.9–48.9, 47.9); anal-fin base length 33.9 (31.7–33.9, 32.5); caudal-fin length 21.8 (21.7–21.9, 21.8); pectoral-fin length 19.6 (18.5–20.9, 19.7); pelvic-fin length 21.9 (21.9–31.8, 26.6); distance between pelvic-fin bases 9.0 (7.6–9.7, 8.8).

Head moderately depressed and of moderate width, eyes large and slightly raised above head profile and lacking tentacles, interorbital area almost flat. Snout and interorbital area crossed by numerous small ridges giving it a wrinkled appearance. The area behind the eyes also with these small ridges, but they are curved back becoming parallel to the body onto the nape forming a horseshoe shape ( Fig. 2 ). Posterior nostril adjacent to eye and hidden in ridges. Anterior nostril just above upper jaw, consisting of tube with a multifid fringe at the end and the opening at the side of the base. A funnel-shaped pit at top of pectoral-fin axil, with glandular tissue inside and extending from ventral pit margin into the axil and onto the side under the pectoral fin, giving the area a very wrinkled appearance ( Fig. 3 ). No scales. Two lateral lines. The upper line begins above the opercular spine, curves up to the second dorsal fin and extends along its base to its end. The lower line begins under the pectoral fin and extends back along the anal fin to the caudal peduncle. A single row of pointed teeth in the upper jaw. The sides of the lower jaw with a single row of teeth and a patch of teeth at the symphysis.

Color of freshly collected holotype ( Fig. 1 ) Background color of head and body brown with a greenish tinge, overlaid with small dark brown to black spots on sides and dorsum up to first dorsal fin. Small dark spots also present on pectoral-fin base. Side of head a darker brown and lacking spots. Snout and jaws dark brown, pupil and iris of eye dark brown to black. Bottom of mouth white, overlaid with yellow. Dorsum from front of second dorsal fin forward onto nape lighter with a yellowish tinge. Underside of head and abdomen white. White spots of ventral lateral line pores visible on side of abdomen. Pelvic fin with white anterior edge along spine, followed by a black line and greenish-tan color on rays and membranes. Anal fin light tan on basal half, distal portion greenish-tan ( Fig. 4 ).

First dorsal fin with a yellowish tinge similar to color of nape. Second dorsal fin yellow-orange with dark brown spots along its base ( Fig. 5 ). Caudal fin with dark brown spots, similar to those on the body on its base, remainder of the fin greenish tan. Inside of pectoral-fin axil white with yellow at the center, reticulations of gland obvious ( Fig. 3 ). A single dark spot on upper part of inside of fin.

Color of preserved holotype. Background color of head and body dark gray with few of the dark spots present in fresh specimens obvious in the holotype (spots more obvious in paratypes). Dark spots on pectoral-fin base, which is lighter, obvious, as are those on the caudal-fin base. Dorsal and caudal fins dark gray. Basal portion of anal fin cream, and distal portion gray. Pectoral fin light gray.

Distribution. Known only from Park Rynie, KwaZulu-Natal, South Africa.

Etymology. The specific epithet, iselesele , is isiZulu for toad, referring to the common name of the fishes in the family Batrachoididae , and is treated as a noun in apposition.

Comparisons. The genus Austrobatrachus was described for Pseudobatrachus foedus Smith, 1947 by Smith (1949). Smith (1952) recognized this as a monotypic genus, commenting that it is “Easily recognizable among South African forms by the peculiar transverse wrinkling on the front of the head.” Menon (1963) utilized the genus Austrobatrachus for Batrachus dussumieri Valenciennes from Malabar, India, as did Hutchins 1981, 1984; Randall 1995; and Carpenter et al. 1997. Greenfield (2006) recognized that the species did not belong to the genus Austrobatrachus and described the genus Colletteichthys for it, leaving A. foedus as the only species in the genus.

Austrobatrachus iselesele is easily distinguished from A. foedus by its distinctive live coloration of black spots on the side and pectoral-fin base and a second dorsal fin that is solid in color. Austrobatrachus foedus has distinct bars crossing the body and lacks dark spots, and has light lines crossing the second dorsal fin at an angle ( Fig. 6 ). In addition, A. iselesele has a longer snout than A. foedus , 5.1 or greater versus 3.0 or less, and a larger eye. In A. iselesele the eye is about equal to the caudal peduncle depth, whereas it is a little more than half of the depth in A. foedus . Austrobatrachus foedus is known only from Algoa Bay to Coffee Bay, Transkei. Austrobatrachus iselesele is known only from the KwaZulu-Natal region to the north.

Remarks. Connell reported that A. iselesele is not common and the specimens he collected were captured between 49– 50 m. He has not observed the species in deeper water and only saw an individual outside of a hole once in the daytime. The fish appears to choose holes into which it fits snugly. No other toadfish species were observed in the area. Upon examining the gut contents he found that they were feeding on whole molluscs, something I have observed from x-rays of other toadfish species. Connell reported that the following species were present in the stomachs: Amalda optima , Colubraria c.f. castanea, Harpa queketti , Phalium labliatum , and Ranella sp. Connell requested that the Zulu name for toad, iselesele , be used for the species.

The allopatric occurrence of two congeners is not unusual in toadfishes. Greenfield et al. (2008) cited examples from Batrachomoeus , Halophryne , Opsanus , Porichthys , and Sanopus and suggested that their limited dispersal ability, due to demersal eggs and larvae that stay attached to the substratum and do not move up into the water column, contributed to the restricted distributions.

With the description of A. iselesele , the number of monotypic toadfish genera is further reduced. Greenfield (2012) has recently demonstrated that the genus Colletteichthys also is no longer monotypic. Of the 23 valid genera, only eight are now monotypic.

Figures

FIGURE 1. Freshly collected holotype of Austrobatrachus iselesele. Photograph by A. Connell.

FIGURE 2. Dorsal view of head of preserved holotype of Austrobatrachus iselesele showing ridges. Photograph by D. W. Greenfield.

FIGURE 3. Pectoral-fin axil of freshly collected holotype of Austrobatrachus iselesele showing axillary foramen. Photograph by A. Connell.

FIGURE 4. Anal fin of freshly collected holotype of Austrobatrachus iselesele. Photograph by A. Connell.

FIGURE 5. Second dorsal fin of freshly collected holotype of Austrobatrachus iselesele. Photograph by A. Connell.

FIGURE 6. Underwater photograph of Austrobatrachus foedus, Algoa Bay, South Africa. Photograph by J. Swanepoel.