Kenyaconger heemstrai, Smith, David G. & Karmovskaya, Emma S., 2003

Smith, David G. & Karmovskaya, Emma S., 2003, A new genus and two new species of congrid eels (Teleostei: Anguilliformes: Congridae) from the Indo­West Pacific, with a redescription and osteology of Chiloconger dentatus, Zootaxa 343, pp. 1-19 : 15-18

Kenyaconger heemstrai sp. nov. ( Figs. 10 –12)

Type material: Holotype, SAIAB 13954 (male, 267 mm TL), 2° 50' S, 40° 31' W, 275 m, R/V "Fridjof Nansen."

Diagnosis. A congrid eel of the subfamily Bathymyrinae . Snout short, bluntly rounded. Posterior nostril opening ventrally from a tube on upper lip behind labial flange. Maxillary and mandibular teeth biserial anteriorly, uniserial posteriorly, compressed and incisor­like, closely appressed.

Description. Measurements: TL 267 mm, preanal length 118 mm (44.2 % TL), predorsal length 48 mm (18.0 % TL), head length 48 mm (18.0 % TL), depth at gill opening 19.5 mm (7.3 % TL), depth at anus 15.8 mm (5.9 % TL), snout 7.7 mm (16.0 % head), eye 9.2 (19.2 % head), upper jaw 12.7 mm (26.5 % head), gill opening 6.9 mm (14.4 % head), interbranchial 6.5 mm (13.5 % head), pectoral fin 14.7 mm (30.6 % head). Meristic characters: preanal LL pores 43­44, POM pores 8,, IO pores 5, SO pores 3, STC pores 0, predorsal vertebrae 9, preanal vertebrae 46, total vertebrae 139.

A moderately stout eel, anus before midlength, head deeper than body, tail blunt and stiffened ( Fig. 10 ). Dorsal­fin origin directly above pectoral­fin base, continuous around end of tail with caudal and anal fins; caudal fin broadly rounded, its rays reduced in length, shorter than adjacent dorsal and anal rays; anal­fin origin immediately behind anus; pectoral fin well developed. Gill opening a crescentic slit on lower side of body, distance from dorsal to ventral ends very slightly greater than interbranchial distance; dorsal end of gill opening opposite ventral end of pectoral­fin base.

Head deeper than body, snout blunt and rounded ( Fig. 11 ). Small dermal filaments on skin of head. Eye large, its diameter greater than snout length. Anterior nostril a short tube above upper lip, set off from lip ventrally by a shallow groove continuous with the groove setting off labial flange. Posterior nostril opening through a tube situated just above edge of upper lip immediately behind labial flange; outer side of tube extends ventrally past edge of upper lip, inner side of nostril tube incised. A prominent upturned flange on upper lip, beginning at anterior nostril with a shallow groove separating flange from side of head; width of flange increases posteriorly, posterior half of flange large and thick, covering a deeply excavated space; flange ends near a vertical through anterior margin of eye, immediately anterior to posterior nostril tube. A fleshy inner lip covering maxillary teeth laterally. A prominent downturned flange on lower lip.

Head pores mostly small and difficult to see, the total number and arrangement uncertain ( Fig. 11 ). Three pores visible in supraorbital series: one pore at tip of snout (the ethmoidal pore); one pore just above base of anterior nostril; one pore on side of head just before anterior margin of eye. Five pores visible in infraorbital series: one relatively large pore just behind base of anterior nostril, partially concealed in groove between labial flange and side of head; a papilla­like pore on side of head, concealed by posterior part of labial flange; a papilla­like pore on side of head immediately behind base of posterior nostril tube; a papilla­like pore on side of head between posterior nostril and rictus; a papillalike pore on side of head 5–6 mm behind rictus (on left side; pore not visible on right side); no postorbital pores. Preoperculomandibular pores small and papilla­like, difficult to see, apparently eight, five before rictus and three behind. No pores visible in supratemporal commissure.

Teeth ( Fig. 12 ) small, conical to blade­like. Intermaxillary teeth conical, slightly recurved, arranged in a patch of three to four irregular transverse rows, the patch somewhat broader than long. Vomerine teeth conical, somewhat shorter and blunter than those of intermaxillary, in a short rounded patch immediately behind intermaxillary teeth, with a narrow posterior extension. Maxillary teeth uniserial for most of length of series, biserial at anterior end of series; teeth of short outer series conical and closely appressed to main (inner) series; teeth of inner series compressed and incisor­like, closely spaced, forming a cutting edge, posteriormost few teeth blade­like and directed anteriorly; maxillary tooth row covered laterally by a sheath­like inner lip, separated from the thick outer lip. Mandibular teeth in a multiserial patch of conical, slightly recurved teeth anteriorly, the patch narrowing posteriorly, becoming uniserial at a point slightly anterior to midpoint of series; teeth in the uniserial portion incisor­like, the tips squared off, closely spaced and forming a cutting edge, except for the posteriormost two or three, which are blade­like and curved anteriorly.

Color medium brown, slightly paler ventrally; dorsal, anal and caudal fins dark­edged. Comparison with other species. The new species is clearly a member of the subfamily

Bathymyrinae as defined by Smith (1989: 490): preanal length more than 40% TL; caudal fin reduced and tip of tail stiff; dorsal­ and anal­fin rays unsegmented; well developed flange on upper lip; teeth small. The new species differs from all other bathymyrines, and indeed from all other congrid eels, in the form of the posterior nostril. Bathymyrines tend to have the posterior nostril displaced ventrally, below mid­eye level. Parabathymyrus has the nostril near the lip and covered by a flap from above. In Parabathymyrus , however, the nostril is on the side of the snout above the labial flange. In Kenyaconger heemstrai , the nostril opens on the edge of the lip itself, behind the labial flange, and the flap has become a tube.

Smith (1989: 490) observed that the Bathymyrinae could be further subdivided into two groups, one containing Paraconger Kanazawa, 1961 and Chiloconger Myers and Wade, 1941 , and the other containing Ariosoma Swainson, 1838 , Bathymyrus Alcock, 1889 , and Parabathymyrus Kamohara, 1938 . Of the five characters used to separate these two groups, two are osteological (presence or absence of the supraoccipital bone, and simple vs. trifurcate urohyal), and one is larval (a single row of melanophores midlaterally vs. a series of short slashes just below the midlateral line). None of these characters can be determined for the new species. The fourth character is the adnasal pore, present in Paraconger and Chiloconger but absent in the others. Further study casts some doubt on this last character, however, as Chiloconger dentatus may lack it. The latter species has a small pore immediately above the anterior nostril, but this may be a supraorbital pore rather than the adnasal pore. The fifth character is the presence ( Ariosoma group) or absence ( Paraconger group) of the third and fourth infraorbital pores. The new species clearly lacks an adnasal pore, and it has the third and fourth infraorbital pores. These characters indicate that the new species belongs to the Ariosoma ­ Bathymyrus ­ Parabathymyrus group, but information on osteology and larval morphology is needed to confirm this conclusion.

Distribution and habitat. The only known specimen was collected in 275 m off the coast of Kenya in the western Indian Ocean.

Etymology. Named for Philip C. Heemstra of the South African Institute for Aquatic Biodiversity, who collected and preserved the holotype while on board the "Fridjof Nansen"; in recognition of his many contributions to our knowledge of the fishes of the western Indian Ocean.

Figures

FIGURE 10. Kenyaconger heemstrai, holotype, SAIAB 13954, 267 mm TL.

FIGURE 11. Kenyaconger heemstrai, holotype, head and anterior body.

FIGURE 12. Kenyaconger heemstrai, holotype, upper (left) and lower (right) dentition.