Parauchenoglanis dolichorhinus, 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) : -

Parauchenoglanis dolichorhinus sp. nov.

( Fig. 8)

Common English name: Long-snouted grunter.

Common French name: Mâchoiron à long museau.

Holotope: SAIAB 84886, 139.8 mm SL, Angola, Kwanza Basin , Posto 5 (09°48 ʹ 23″S, 15°24 ʹ 30″E); DNA sample ES07F442: SB9092; collector Ernst Swartz, 31 October 2007 .

Paratopes (N = 3): Angola: RMCA _ Vert _P.0002 (ex SAIAB 235745 ), one, 115.1 mm SL, Kwanza Basin, Posto 5 (09°48 ʹ 23″S, 15°24 ʹ 30″E); DNA sample ES07F296: SB9090; collector Ernst Swartz, 24 October 2007 . SAIAB 235745 , one, 91.9 mm SL, Kwanza Basin , Posto 5 (09°48 ʹ 23″S, 15°24 ʹ 30″E); collector Ernst Swartz, 24 October 2007 . SAIAB 85066 , one, 52.4 mm SL, Kwanza Basin , New dam site (09°41 ʹ 35″S, 14°59 ʹ 55″E); DNA sample ES08B148 : SAFW418-08 ; collector Ernst Swartz, 16 August 2008 .

Diagnosis: Parauchenoglanis dolichorhinus is distinguished from P.ahli , P. altipinnis , P. balaoi , P. buetikoferi , 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. balaoi , P. pantherinus , and P. punctatus by coarse skin (vs. smooth skin). It is differentiated from P. buetikoferi 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 dolichorhinus is distinguished from P. zebratus by humeral process clearly visible through the skin, presence of five to six bars on small or vertical rows of spots on large, 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 dolichorhinus is distinguished from P. stiassnoae by the absence of black background spots in between the vertical bars or rows of spots (vs. reticulated paưern), a depressed head, head depth 34.6%–40.0% HL (vs. moderately depressed head, head depth 43.5%–58.7% HL), and a narrow body depth, 11.6%–14.0% SL (vs. a deeper body depth, 15.7%–22.7% SL). Parauchenoglanis dolichorhinus is distinguished from all other species of the P. ngamensis species group by a depressed head; head depth 34.6%–40.0% HL (vs. a moderately depressed head; head depth 40.6%–60.8% HL in P. ngamensis , 48.5%–54.9% HL in P. patersoni , 41.2%–50.3% HL in P. lueleensis , 41.7%–42.0% HL in P. poikilos , 49.5%–54.0% HL in P. ernstswartzi , 42.0%–53.5% HL in P. chiumbeensis , and 48.2%– 59.2% HL in P.luendaensis ). It is further distinguished from these species by narrow body depth, 11.6%–14.0% SL (vs. deeper body depth, 14.6%–23.5% SL in P. ngamensis , 15.5%–21.4% SL in P. patersoni , 15.0%–17.4% SL in P. lueleensis , 16.0%–16.2% SL in P. poikilos , 18.2%–19.9% SL in P. ernstswartzi , 20.2%–20.9% SL in P. megalasma , 14.8%–21.3% SL in P. luendaensis , and 14.5%–18.9% SL in P. chiumbeensis ). It is further distinguished from P. lueleensis , P. poikilos , P. ernstswartzi , and P. megalasma by a narrow interpectoral distance, 17.4%–18.2% SL (vs. wider, 18.8%–22.5% SL in P. lueleensis , 18.4%–21.0% SL in P. poikilos , 19.8%–20.6% SL in P. ernstswartzi , and 18.8%–21.9 % SL in P. megalasma ). Finally, it is further distinguished by unspoưed fins [ Fig. 8A; vs. fins with numerous black spots in P. ngamensis ( Fig. 5A), P. lueleensis ( Fig. 10A), and P. poikilos ( Fig. 11A) or faint spots in P. chiumbeensis ( Fig. 15A) or blotches in P. ernstswartzi ( Fig. 12A) and P. megalasma ( Fig. 13A)].

Description: Morphometric and meristic data are given in Table 3. A medium-sized species with a maximum observed size of 139.8 mm SL. Body elongated and dorsally depressed from snout tip to origin of dorsal fin. Dorsal body profile convex from tip of snout to dorsal fin origin, straight from dorsal-fin origin to caudal-fin base. Body depth highest at origin of dorsal fin. Ventral body profile slightly concave from lower jaw to 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 edge of pectoral fin rays does not reach pelvic fins. Entire posterior margin of the pectoral-fin spine serrated, and anterior margin serrated only towards distal end. Caudal fin rounded.

Head depressed. Snout profile bluntly triangular, on dorsal view ( Fig. 8B). Mouth subterminal. Lips fleshy. Eyes small and situated dorsolaterally. Ŋree 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.

Colouration in life: Body yellow-brown to light brown dorsally and laterally. Distal tips of fins with brown markings (Supporting Information, Fig. S3). Arrangement of spots is discussed below.

Colouration in alcohol: Body light brown dorsally and laterally, and cream ventrally. Body with five to six bars in medium-sized specimens (52.4–91.9 mm SL; Fig. 9). Large-sized specimens (115.1–139.8 mm SL) with black spots smaller than the eye forming six vertical rows. No additional black spots in between the bars or vertical rows of spots. Head light brown, sometimes with very few, usually <10 black spots, smaller than those on body. Fins with a few black spots, sometimes even unspoưed. Distal tip of fin rays with black markings. Usually, two small black spots present above gill opening and one spot on midline of caudal-fin base. Barbels unspoưed.

Distribution: Parauchenoglanis dolichorhinus has currently been recorded only from the mainstream section of the Kwanza Basin above and below the Quissaquina Falls ( Fig. 1). Ŋis species co-occurs with the other Kwanza endemic Parauchenoglanis species, P. patersoni .

Etomologo: Ŋe species name ‘ dolichorhinus ’ is derived from the Greek ‘ dolichos ’ meaning long and ‘ rhinus ’ meaning snout, referring to the long snout (preorbital length) of this species in comparison to the other species in the P. ngamensis group.