Kaupichthys atronasus Schultz, 1953

Smith, David G., Bogorodsky, Sergey V. & Mal, Ahmad O., 2014, Records of the eels Kaupichthys atronasus (Chlopsidae), Phyllophichthus xenodontus (Ophichthidae), and Gorgasia preclara (Congridae) from the Red Sea, Cybium 38 (4), pp. 301-306 : 301-302

Kaupichthys atronasus Schultz, 1953

( Fig. 1 )

Kaupichthys atronasus Schultz, 1953: 65 , fig. 14 (Marshall Is.); holotype USNM 141260. Böhlke and Smith, 1968: 27 (Solomon Is. and New Britain, additional meristic data given). Asano, 1984: 22 ( Japan). Paxton et al., 1989: 137 ( Australia). Winterbottom et al., 1989: 6 (Chagos Archipelago, Indian Ocean). Myers, 1999: 41-42 (throughout Micronesia). Tighe, 2000 (South China Sea). Allen and Adrim, 2003: 22 ( Indonesia). Allen et al., 2007 ( Christmas Island, Indian Ocean). Fricke et al., 2011: 349 ( New Caledonia). Allen and Erdmann, 2012: 73 (Red Sea, etc.).

Material

USNM 313654 (1 specimen, 128 mm TL), Egypt, NW coast Gulf of Aqaba , 0-18 m, 16 Jul. 1969 , Springer et al. coll.; SMF 34947 (1 spm, 76 mm TL), 20°15.211’N, 39°59.380’E, Saudi Arabia, Al-Lith , 10 m, 08 Mar. 2012, Bogorodsky and Alpermann coll.

Description (based on two Red Sea specimens)

In % TL: preanal 33, predorsal 14-15, head 13-14, depth at anus ca 3. In % head length: snout 17-20, eye 7-10, interorbital 17-19, snout-rictus 30-31, pectoral fin 20. Pores: LL 1, POM 6, IO 4 , SO 3, ST 0. Pectoral-fin rays 10. Vertebrae: PD 10 , PA 32, Total 112 (2 specimens) .

Body moderate in length, anus near first third of TL. Dorsal and anal fins confluent with caudal fin, dorsal fin begins approximately above gill opening, anal fin begins immediately behind anus; pectoral fins present. Eyes well-developed. Rictus slightly behind posterior margin of eye. Anterior nostril tubular, near tip of snout, directed anterolaterally; posterior nostril on edge of upper lip, near anterior margin of eye. Lateral line reduced, only a single pore in branchial region anterior to gill opening. Teeth small and conical; intermaxillary teeth in a short patch at anterior end of roof of mouth; maxillary and dentary teeth in narrow rows; vomerine teeth in two long series on each side, widely diverged, each closer to maxillary series than to its counterpart on other side.

Three supraorbital pores: one at tip of snout just above lip (the ethmoidal pore, by convention treated as part of the supraorbital series), one at tip of snout just above previous one, and one on top of snout medial to anterior nostril. Four infraorbital pores along upper lip: one just behind anterior nostril, one between anterior and posterior nostrils, one below anterior margin of eye, one below posterior margin of eye; no pores in ascending branch of canal behind eye. Six pores in mandibular section of preoperculo-mandibular canal, all anterior to rictus; no pores in preopercular section. No pores in supratemporal canal.

Colouration (based on photograph of fresh specimen)

Semitranslucent with small irregular brown blotches on body and head; a large diffuse dark brown blotch behind eye, and dark brown vertical streak before eye; anterior nostril and area immediately around base of nostril black, nostril tips white; red gills visible through skin; fins uniform pale grey. Colour of preserved specimens similar, with some variation in intensity of brown blotches.

Distribution and habitat

Central Pacific and Indian Ocean, from the Marshall Islands to the Red Sea; in the Pacific from Japan in the north to Australia in the south; in the Indian Ocean reported from Chagos Archipelago and Christmas Island only ( Winterbottom et al., 1989; Allen et al., 2007). Found in shallow water around coral reefs; most specimens collected with ichthyocide. Specimen from Al Lith, Saudi Arabia, was collected from a crevice, deep inside the fringing reef at a depth of 10 m.

Remarks The species of the genus Kaupichthys occur in all oceans.

Three species are known from the Indian Ocean: K. atronasus , K. brachychirus and K. diodontus , all described by Schultz, 1953. The latter two are easily distinguished by their plain brown colour; K. brachychirus is characterised by very short pectoral fins. Randall et al. (1997) reproduced a photo of a fresh specimen of K. atronasus and described the tip of the snout as black. We examined 28 lots of Kaupichthys atronasus from all over the Indo-Pacific, and all have the same colour pattern as the Red Sea specimens: snout colour like the head, with a black blotch around the base of anterior nostrils only. In none was the tip of the snout black. As mentioned above, there is some variation in the intensity of the brown blotches, and we suspect that Randall et al. (1997) may simply have had a specimen with unusually dark blotches and interpreted this as black. There is very little geographic variation in Kaupichthys atronasus over its range. The holotype from the Marshall Islands has 114 vertebrae, and the two specimens from the Red Sea both have 112. Chlopsid eels tend to be remarkably uniform in their main characters, showing little variation in colour, pores and vertebral number, and proportions within species. It is possible that genetic data would show more heterogeneity, but such data are not yet available for this species.

Figures

Figure 1. - Kaupichthys atronasus, SMF 34947 (76 mm TL). Photo S. Tränkner. Scale bar = 10 mm.