Parauchenoglanis lueleensis, 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 : 21-22

Parauchenoglanis lueleensis sp. nov.

( Fig. 10 ; Table 3 )

Common English name: Luele grunter.

Common French name: Mâchoiron de la Luele.

Holotype: SAIAB 118796 , 95.4 mm SL, Angola, Kasai sub-basin, Luxico, above drift in tributary 2 (7°45 ʹ 05.7″S, 19°57 ʹ 18.8″E); DNA sample ES11-BT103: SB8998; collectors Ernst Swartz and Cotterill P.D. Fenton; 29 April 2011 .

Paratypes (N = 13): Angola: RMCA_Vert_P.0003 (ex SAIAB 118850), one, 158.5 mm SL, Kasai sub-basin, Luxico, above confluence with main river in tributary 2 (7°45 ʹ 7.0″S, 19°57 ʹ 19.6″E); DNA sample ES11-BT049: SB8999; collectors Ernst Swartz and Cotterill P.D. Fenton; 29 April 2011. SAIAB 99425 , three, 53.2–91.6 mm SL, Kasai sub-basin, Luxico, above confluence with main river in tributary 1 (7°45 ʹ 09.2″S, 19°57 ʹ 22.8″E); DNA sample ES11-BT124: SB8997; collectors Ernst Swartz and Cotterill P.D. Fenton; 2 May 2011. SAIAB 99230 , five, 39.0– 21.8 mm SL, Kasai sub-basin, Luxico, Luele Rapids above the confluence with the Luxico River (7°45 ʹ 01.6″S, 19°56 ʹ 58.8″E); DNA sample ES11-BT083: SB8990 and ES11-BT084: SB8991; collectors Ernst Swartz and Cotterill P.D. Fenton; 1 May 2011. SAIAB 99421 , four, 17.2–70.72mm SL, Kasai sub-basin, Luxico, between Lake Carumbo and the confluence with the Luele River (7°45 ʹ 29.4″S, 19°56 ʹ 34.3″E); DNA sample ES11-BT060: SB8994 and ES11-BT059: SB8995; collectors Ernst Swartz and Cotterill P.D. Fenton; 1 May 2011.

Diagnosis: Parauchenoglanis lueleensis 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 lueleensis is distinguished from P. zebratus by humeral process clearly visible through the skin, presence of six to seven vertical rows of spots regardless of the size, and anterior margin of the pectoral-fin spine mostly smooth (vs. humeral process embedded under the skin, four to five vertical rows of spots on small specimens or four to five bars on larger specimens, and anterior margin of the pectoral-fin spine mostly serrated). Parauchenoglanis lueleensis is distinguished from P. stiassnyae by the dorsolaterally positioned eyes (vs. dorsally) and spotted fins (vs. unspotted pectoral, pelvic, and anal fin). Parauchenoglanis lueleensis is distinguished from all other species in the P. ngamensis group by one or two black background spots in between vertical rows of spots [ Fig. 10A ; vs. absent background spots in P. patersoni ( Fig. 11A ), P. dolichorhinus ( Fig. 8A ), P. luendaensis ( Fig. 14A ), and P. chiumbeensis ( Fig. 15A ) or numerous spots in P. ngamensis ( Fig. 5A ) and P. poikilos ( Fig. 11A ) or vermiculated pattern on the background in P. ernstswartzi ( Fig. 12A ) or blotches in P. megalasma ( Fig. 13A )]. It is further differentiated from P. luendaensis by spotted fins ( Fig. 10A ; vs. unspotted in P. luendaensis , Fig. 14A ). It is further differentiated from P. ernstswartzi and P. megalasma by shallow body depth, 15.0%–17.4% SL (vs. deeper, 18.2%–19.9% SL in P. ernstswartzi and 20.2%–20.9% SL in P. megalasma ). It is further differentiated from P. dolichorhinus by deeper head, 41.2%–50.3% SL (vs. smaller head depth in P. dolichorhinus , 34.6%–40.0% SL) and wider interpectoral distance, 18.8%–22.5% SL (vs. narrow interpectoral distance in P. dolichorhinus , 17.4%–18.2% SL).

Description: Morphometric and meristic data are given in Table 3 . Body elongated. Dorsal body profile gently rising from snout tip to dorsal-fin origin, 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 base and anal-fin origin, ending posteriorly to end of anal-fin base. Dorsal and pectoral fins with strong spine. Dorsal-fin origin anterior to pelvic-fin origin. Posterior tip of pectoral-fin rays does not reach pelvic fin. Entire posterior margin of the pectoral-fin spine serrated, and anterior serrated only towards distal end. Caudal fin truncated.

Head moderately depressed. Snout profile bluntly triangular, on dorsal view ( Fig. 10B ). 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 middle of eye. Maxillary barbel reaching beyond posterior edge of the eye but not reaching the base of pectoral-fin spine. Posterior nostril slits positioned about halfway between snout tip and eye.

Colourationinalcohol: Bodybrowndorsallyandlaterally,andcream ventrally. Body with black spots smaller than the eye forming six to seven vertical rows of black spots, at all sizes. One or two faint spots present in between vertical rows. Head brown, with black spots, smaller than those on body mostly in small-sized specimens and sometimes even unspotted or with small black spots present only on edge of the operculum. Fins with small black spots. No markings on distal tips of fin rays. Usually, one or two small black spots present above the gill opening. Barbels unspotted.

Distribution: Parauchenoglanis lueleensis is known from the Luele River and its right bank affluent, Luxico River (Luchico sensu Poll 1967). Both are tributaries of the Loange River, a left bank affluent of the Kasai River (see Poll 1967), itself a left bank affluent of the middle Congo Basin.

Etymology: Parauchenoglanis lueleensis is named after the Luele River, Kasai sub-basin, Angola, where this species is currently known to occur. The suffix ‘- ensis ’, meaning ‘lives in’, has been added.

Figures

Figure 5. Photographs of the holotype of Parauchenoglanis ngamensis, BMNH 1910.5.31.35, 184.5 mm SL, Okavango River.A, lateral view.B, dorsal view. C, ventral view. Scale bar: 1 cm.

Figure 8. Photograph of the holotype of Parauchenoglanis dolichorhinus, SAIAB 84886, 139.8 mm SL, Kwanza River. A, lateral view.B, dorsal view. C, ventral view. Scale bar: 1 cm.

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.