Petrocephalus squalostoma ( Boulenger, 1915 )

Kramer, Bernd, Bills, Roger, Skelton, Paul & Wink, Michael, 2012, A critical revision of the churchill snoutfish, genus Petrocephalus Marcusen, 1854 (Actinopterygii: Teleostei: Mormyridae), from southern and eastern Africa, with the recognition of Petrocephalus tanensis, and the description of five new species, Journal of Natural History 46 (35 - 36), pp. 2179-2258 : 2245-2246

Petrocephalus squalostoma ( Boulenger, 1915)

(Online Figure 12 )

Marcusenius squalostoma Boulenger, 1915: 162 .

Petrocephalus squalostoma ( Boulenger, 1915) : Taverne 1972: 162. Current status: valid as Petrocephalus squalostoma ( Boulenger, 1915) .

Type specimens. Syntypes: (5) BMNH 1920.5.26.1(2) studied , MRAC 14352-54 (3), not studied .

Type locality. Tributary of Lukinda River , a tributary of Moero Lake, Democratic Republic of Congo, estimated at 8.51 ◦ S, 28.96 ◦ E (coordinates cited from Lavoué Forthcoming 2012) .

Diagnosis. Number of dorsal fin rays, nD, 18–21; of anal fin rays, nA, 29–31; predorsal length, PDL, 0.6671 –0.673 of SL; preanal length, PAL, 0.598 –0.603 of SL; body depth, BD, 0.329 –0.335 of SL; caudal peduncle depth, CPD, 0.346 –0.388 of CPL, caudal peduncle length; length of snout to posterior orbital rim of eye, LSo, 0.409 –0.441 of

head length, HL; distance anterior base of pectoral fin to anterior base of pelvic fin, PPF, 0.198 –0.208 of SL; length of dorsal fin, LD, 0.160 –0.174 of SL .

Description. Body asymmetrically oval shape with long, prominent, arched back and deep body. Head broadly rounded, with very short snout to posterior orbital rim, LSo, 0.409 –0.441 of head length, HL. HL 0.263 –0.280 of SL. Eye diameter, OD, 0.223 –0.257 of HL. Small mouth ventrally located under the eye; head and body dorsolaterally compressed. Dorsal fin set far back, at about two-thirds of standard length from snout, starting above the fourth or fifth ray of the anal fin. Predorsal length, PDL, 0.667 –0.673, preanal length, PAL, 0.599 –0.603. Number of dorsal fin rays, nD 18–21, of anal fin rays, nA 29–31. Anal fin, LA, with 0.241 –0.250 of SL longer than and opposite dorsal fin, with length, LD, 0.160 –0.174 of SL. Forked tail fin with rounded, slightly pointed lobes on slender, subcylindrical caudal peduncle the depth of which, CPD, is 0.346 –0.388 its length, CPL. Length of pectoral fins, LPF, 0.638 − 0.689 of HL. Length of caudal peduncle, CPL, 0.184 –0.192 of SL. Scales extending anteriorly to operculum and pectoral fins. The number of circumpeduncular scales, SPc, 12. Body depth, BD, 0.329 –0.335 of standard length. Pectoral to pelvic fin distance, PPF, 0.198 –0.208 of SL.

Colour in preservation. Homogeneously brown.

Ecology. Unknown.

Remarks. Values for PDL, PPF and BD that are either highest or in the uppermost range among the present assemblage of Petrocephalus species are distinctive of P. squalostoma .

Etymology. Perhaps from Latin squalidus, without ornament, and Greek stoma, mouth.

Figures

Figure 12. Least-squares regression of the EOD character P2amp with SL in southern and eastern African Petrocephalus species. Top, females, bottom, males. In P. longicapitis sp. nov. and P. wesselsi regression line slopes fall with SL and are about equal in contrast to their y-intercepts, which differ significantly. Petrocephalus tanensis differs from the other two species in showing no falling slope or even a steep rise (females). Stippled line, regression not significant (P> 0.05).