Parauchenoglanis poikilos, Sithole & Vreven & Bragança & Musschoot & Chakona, 2024

Sithole, Yonela, Vreven, Emmanuel J. W. M. N., Bragança, Pedro H. N., Musschoot, Tobias & Chakona, Albert, 2024, Nine in one: integrative taxonomic evidence of hidden species diversity in the widespread Zambezi grunter, Parauchenoglanis ngamensis (Siluriformes: Auchenoglanididae), from southern and south-central Africa, Zoological Journal of the Linnean Society 202 (3), pp. 1-33 : 22-23

Parauchenoglanis poikilos sp. nov.

( Fig. 11 ; Table 3 )

Common English name: Spotted grunter.

Common French name: Mâchoiron tachetés.

Holotype: SAIAB 99100 , 57.2 mm SL, Angola, Kasai sub-basin, Lovua, Opposite Capeia Village on bamboo track (8°20 ʹ 16.3″S, 20°14 ʹ 29.0″E); DNA sample ES11-BT218: SB9000; collectors Ernst Swartz and Fenton P.D. Cotterill; 5 July 2011 .

Paratype (N = 1): Angola: SAIAB 235744 (ex SAIAB 99100), one, 36.3 mm SL, collection details same as for holotype; DNA sample ES11-BT204: SB8977 .

Diagnosis: Parauchenoglanis poikilos is distinguished from P. ahli , P. altipinnis , P. balayi , P. buettikoferi , P. longiceps , P. monkei , P. pantherinus , and P. punctatus by a broad humeral process (vs. pointed humeral process). It is further distinguished from P. altipinnis , P. balayi , P. pantherinus , and P. punctatus by coarse skin (vs. smooth skin). It is differentiated from P. buettikoferi and P. monkei by anterior margin of the pectoral-fin spine mostly smooth (vs. anterior margin of pectoral-fin spine serrated from base to tip). Parauchenoglanis poikilos is distinguished from P. zebratus by humeral process clearly visible through the skin and anterior margin of the pectoral-fin spine mostly smooth (vs. humeral process embedded under the skin and anterior margin of the pectoral-fin spine mostly serrated). Parauchenoglanis poikilos is distinguished from P. stiassnyae by dorsolaterally positioned eyes (vs. dorsally) and spotted fins (vs. unspotted pectoral, pelvic and anal fin). Parauchenoglanis poikilos is distinguished from P. patersoni , P. dolichorhinus , P. luendaensis , and P. chiumbeensis by presence of black background spots in between the darker spots constituting the vertical rows ( Fig. 11A ; vs. absent, Figs 11A , 13A , 14A , 15A , respectively). It is further distinguished from P. luendaensis by spotted head and fins ( Fig. 11B ; vs. unspotted, Fig. 14B ). It is distinguished from P. ernstswartzi and P. megalasma by body with vertical rows of spots ( Fig. 11A ; vs. vertical rows of blotches, Fig. 13A ) and bluntly triangular snout [ Fig. 11B ; vs. round snout in P. ernstswartzi ( Fig. 12B ) or partly round snout in P. megalasma ( Fig. 13B )]. Parauchenoglanis poikilos is further distinguished from P. ernstswartzi by lower body depth, 16.0%– 16.2% SL (vs. deeper, 18.2%–19.9% SL in P. ernstswartzi ). It is distinguished from P. dolichorhinus by deeper body, 16.0%– 16.2% SL (vs. shallow, 11.6%–14.0% SL in P. dolichorhinus ). It is differentiated from P. lueleensis by scattered black spots in between vertical rows ( Fig. 11A ; vs. one or two spots in between vertical rows, Fig. 10A ) and spotted mandibular barbels ( Fig. 10B ; vs. unspotted, Fig. 10B ).

Description: Morphometric and meristic data are given in Table 3 . Body elongated. Dorsal body profile gently rising from snout tip to origin of dorsal fin, slightly concave from dorsal-fin origin to adipose-fin origin, and straight from the adipose-fin origin to caudal-fin base. Body depth highest at origin of dorsal fin. Ventral body profile slightly convex from lower jaw to end of caudal-fin base. Caudal peduncle laterally compressed. Anus and urogenital opening positioned about halfway between pelvic- and anal-fin origins. Adipose fin longer than anal-fin base, originating anteriorly to anal-fin origin, between pelvic origin and anal-fin origin, ending posteriorly to end of anal-fin base. Dorsal and pectoral fins with strong spines. Dorsal-fin origin anterior to pelvic-fin origin. Posterior edge of pectoral-fin rays does not reach pelvic fin. Pectoral fine spine serrated along inner posterior margin and towards extremity of outer anterior margin. Caudal fin truncated.

Head moderately depressed. Snout profile bluntly triangular, on dorsal view ( Fig. 11B ). Mouth subterminal. Lips fleshy. Eyes small and situated dorsolaterally. Three pairs of barbels, base thick and tips pointed. External mandibular barbel longest, almost reaching the tip of pectoral-fin spine. Inner mandibular barbel shortest, reaching posterior edge of the eye. Maxillary barbel reaching behind posterior edge of the eye but not reaching the base of pectoral-fin spine. Posterior nostril slits positioned about halfway between tip of snout and eye, and both closer together than the interorbital distance.

Colouration in alcohol: Body brown dorsally and laterally, and cream ventrally. Body with black spots smaller than the eye surrounded by a light brown shade forming six to seven vertical rows. Scattered black spots present in between vertical rows. Head brown, with numerous small black spots, smaller than those on body. Fins with black spots arranged along the rays. No markings on distal tips of fin rays. Two large brown blotches on the end of the caudal peduncle surrounded by a light yellowish brown area and delimited posteriorly by a crescent-shaped marking present on the caudal-fin base. Mandibular barbels (external and inner) with black spots, and maxillary barbel without spots.

Distribution: Parauchenoglanis poikilos is currently known from the Lovua River (Luchico sensu Poll 1967), a left bank affluent of the Kasai River (see Poll 1967), with the latter being a left bank affluent of the middle Congo Basin.

Etymology: The name ‘ poikilos ’ is derived from the Greek adjective ‘ poikilos ’, meaning spotted, in reference to the numerous spots composing its colour pattern.

Figures

Figure 10. Photograph of the holotype of Parauchenoglanis lueleensis, SAIAB 118796, 95.4 mm SL, Luele River (Kasai). A, lateral view.B, dorsal view.C, ventral view. Scale bar: 1 cm.

Figure 11. Photograph of the holotype of Parauchenoglanis poikilos, SAIAB 99100, 57.2 mm SL, Lovua River (Kasai). A, lateral view. B, dorsal view.C, ventral view.Scale bar: 1 cm.

Figure 12. Photograph of the holotype of Parauchenoglanis ernstswartzi, SAIAB 118845, 96.6 mm SL, Lake Carumbo (Kasai). A, lateral view.B, dorsal view. C, ventral view. Scale bar: 1 cm.

Figure 13. Photograph of the holotype of Parauchenoglanis megalasma, SAIAB 118792, 72.5 mm SL, Luele River (Kasai). A, lateral view.B, dorsal view. C, ventral view. Scale bar: 1 cm.

Figure 14. Photograph of the holotype of Parauchenoglanis luendaensis, RMCA_Vert_P.161764, 102.2 mm SL, Luenda River (Kasai). A, lateral view.B, dorsal view. C, ventral view. Scale bar: 1 cm.

Figure 15. Photograph of the holotype of Parauchenoglanis chiumbeensis, RMCA_Vert_P161724, 131.5 mm SL, Chiumbe River (Kasai). A, lateral view.B, dorsal view.C, ventral view. Scale bar: 1 cm.