Parauchenoglanis luendaensis, 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 : 25-27

Parauchenoglanis luendaensis sp. nov.

( Fig. 14 ; Table 3 )

Parauchenoglanis ngamensis ‘luenda’, Sithole et al., 2023.

Common English name: Luenda grunter.

Common French name: Mâchoiron de la Luenda.

Holotype: RMCA_Vert_P. 161764 , 102.2 mm SL, Angola, Kasai sub-basin, River Luenda (9°30 ʹ S, 20°15 ʹ E); collector Max Poll; April 1964 .

Paratypes (N = 9): Angola: RMCA_Vert_P.161761–161763 , three, 61.0– 84.9 mm SL; RMCA_Vert_P.161771–161772 , two, 49.0– 63.3 mm SL; RMCA_Vert_P.161735 , one, 121.2 mm SL; SAIAB 246236 (ex. RMCA_Vert_P.161751–161753), three, 72.9–122.0 mm SL; collection details same as for the holotype .

Diagnosis: Parauchenoglanis luendaensis 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). Parauchenoglanis luendaensis is distinguished from P. zebratus by humeral process clearly visible through the skin, presence of six to seven vertical rows of spots, and anterior margin of the pectoral-fin spine mostly smooth (vs. humeral process embedded under the skin, four to five bars, and anterior margin of the pectoral-fin spine mostly serrated). Parauchenoglanis luendaensis is readily distinguished from P. stiassnyae by truncated caudal fin (vs. rounded), dorsolaterally positioned eyes (vs. dorsally positioned), and the presence of regularly spaced vertical rows of spots on the flank (vs. irregularly spaced blotches). Parauchenoglanis luendaensis is distinguished from P. ngamensis , P. lueleensis , P. poikilos , and P. ernstswartzi by absent background spots [ Fig. 14A ; vs. present black background spots in P. ngamensis ( Fig. 9A ), P. lueleensis ( Fig. 10C ), and P. poikilos ( Fig. 11A ) or vermiculated pattern in P. ernstswartzi ( Fig. 12A ) or blotches in P. megalasma ( Fig. 13A )] and unspotted head [ Fig. 14B ; vs. spotted in P. ngamensis ( Fig. 5B ), P. lueleensis ( Fig. 10B ), P. poikilos ( Fig. 11B ), P. ernstswartzi ( Fig. 12B ), and P. megalasma ( Fig. 13B )]. Parauchenoglanis luendaensis is differentiated from P. chiumbeensis by unspotted head and fins ( Fig. 14B ; vs. faintly spotted head and fins, Fig. 15B ) and relatively high adipose fin height, 6.4%–7.7% SL ( Fig. 14A ; vs. low, 5.1%– 6.8% SL, Fig. 15A ). It is further distinguished from P. poikilos and P. ernstswartzi by relatively shorter prepectoral fin length, 26.2%–29.5% SL (vs. longer, 30.6%–31.4% SL in P. poikilos and 28.6%–30.4% SL in P. ernstswartzi ). It is further differentiated from P. poikilos and P. megalasma by small head, 31.0%–34.5% SL (vs. bigger, 35.0%–35.6% SL in P. poikilos and 34.8%–35.5% SL in P. megalasma ). It is differentiated from P. dolichorhinus and P. patersoni by truncated caudal fin (vs. rounded). It is further distinguished from P. dolichorhinus by moderately depressed head; head depth 48.2%–59.2% HL (vs. depressed head; head depth 34.6%–40.0% HL). Parauchenoglanis luendaensis is further distinguished from P. patersoni by external mandibular barbel reaching distal tip of pectoral-fin spine (vs. not reaching the tip of pectoral-fin spine).

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, dorsal fin base slightly concave, and straight from the origin of the adipose fin 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. Fleshy flanges along the ventral and dorsal edge of the caudal peduncle to caudal fin base. 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 at the end of anal-fin base. Dorsal and pectoral fins with strong spines. Dorsal-fin origin anterior to pelvic-fin origin. Posterior tip of pectoral-fin rays does not reach pelvic fin. Posterior tip of pelvic-fin rays does not reach anal fin. Pectoral-fin spine serrated on the posterior margin, and the anterior margin only serrated towards distal end only. Caudal fin truncated.

Head moderately depressed. Snout profile bluntly triangular, on dorsal view ( Fig. 14B ). Mouth subterminal. Lips fleshy. Eyes small and situated dorsolaterally. Three pairs of barbels, base thick and tips pointed. External mandibular longest, reaching the distal tip of the pectoral-fin spine. Inner mandibular barbel shortest, reaching posterior edge of the eye. Maxillary barbel reaching beyond posterior edge of the eye, sometimes reaching the base of pectoral-fin spine. Posterior nostril slits positioned about halfway between snout tip and eye.

Colouration in alcohol: Body brown dorsally and laterally, and light brown ventrally. Body with black spots smaller than the eye forming six to seven vertical rows of black spots. No additional black spots in between the vertical rows, and this at all sizes. Head brown and unspotted. All fins unspotted. Distal tip of fin rays with no markings. Usually, two small black spots present above gill opening and one spot on caudal-fin base. Barbels unspotted.

Distribution: Parauchenoglanis luendaensis is currently known from the Luenda River, a left bank affluent of the Chicapa River, itself a left bank affluent of the Kasai further upstream of the Lulua, which itself is a right bank affluent of the Kasai River.

Etymology: Parauchenoglanis luendaensis is named after the Luenda 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 9. Photograph of the typical colour pattern of a small-sized specimen of Parauchenoglanis dolichorhinus, SAIAB 85066, 52.4 mm SL, Kwanza River. 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.