Hannia wintoni, Shelley & Delaval & Le Feuvre & Dempster & Raadik & Swearer, 2020

Shelley, James J., Delaval, Aurélien, Le Feuvre, Matthew C., Dempster, Tim, Raadik, Tarmo A. & Swearer, Stephen E., 2020, Revision of the genus Hannia (Teleostei, Terapontidae), with description of a new species, Hannia wintoni, from the Kimberley, Western Australia, Zootaxa 4869 (4), pp. 562-586 : 573-577

Hannia wintoni , new species

Figs. 1 , 5–7 ; Tables 4–6

Recommended standard name: Winton’s Grunter

Hannia sp.— Shelley et al. 2018a: 126.

Hannia greenwayi II—Shelley et al. 2018b: 849–851, 855–856; Shelley et al. 2019b: 2427, Shelley et al. 2020: 1732–1734 .

Holotype: WAM P.35010–001, 166 mm SL, unnamed creek flowing into the lower Prince Regent River , Western Australia; 15° 25’ 1.7’’S, 125° 14’ 13.3”E, 25 m elevation, J.J. Shelley ( JJS) & M.C. Le Feuvre ( MCL), 26 July 2013, gill net.

Paratypes: 11 specimens, 46.6–165 mm SL. WAM P.35011-001, 159 mm SL; WAM P.35010-002, 165 mm SL, collected with Holotype; NMV A 31918-009 (1), 98.0 mm SL, NMV A 31946-030 to 034 (5), 46.6–98.0 mm SL, Prince Regent River at Quail Creek confluence, Western Australia, 15° 42’ 28.8”S, 125° 26’ 20.7”E, 20 m elevation, JJS & MCL, 28 July 2013, electrofisher (one with gill net); NMV A 32035-001 to 003 (3), 62.8–100.5 mm SL, Middle Moran River , Roe River , 15° 22’ 34”S, 125° 44’ 29”E; 200 m elevation, JJS & MCL, 22 July 2013, electrofisher .

Non-type specimens (x-rayed for osteological comparisons only): 8 specimens, 58.4–145.8 mm SL. NMV A 31566-006 , 010 to 014 (5), 84.3–145.8 mm SL, collected with Holotype ; NMV A 31918-008 (3), 58.4–90.1 mm SL, Prince Regent River at Pitta Creek confluence, 15° 42’ 28.8”S, 125° 26’ 20.7”E, 140 m elevation , JJS & MCL, 30 July 2013, electrofisher .

Diagnosis: Hannia wintoni sp. nov. can be best distinguished from its congener by its substantially larger size as an adult (recorded up to 200 mm SL), and by the combination of the following characters: a convex posterior nape profile, with a slight hump forward of the first dorsal spine before the nape continues anteriorly as a straight slope; pectoral fin rays usually 15; preopercular spines usually 19; and, postorbital length 36.9 (35.1–40.8) % HL. Secondary characters to further aid discrimination are: dorsal fin rays usually 9, fifth spine and second ray longest; first anal fin ray and first pelvic fin ray longest; lateral line scales 37; pre-dorsal scales usually 11; caudal circumpeduncular scales 18. Body depth at dorsal fin origin 35.9 (33.5–39.8) % SL; body depth at anal fin origin 30.4 (27.8–34.2) % SL; snout length 39.3 (36.0–44.6) % HL; jaw width 33.0 (28.6–37.6) % HL; pectoral fin length 21.7 (19.8–23.8) % SL; dorsal fin length 57.5 % SL; pelvic fin length 24.0 (22.0–26.1) % SL; caudal peduncle depth 11.5 (7.5–13.3) % SL; longest anal fin length 14.5 (11.4–17.2) % SL.

Description: Based on the 12 type specimens, 61.8–166 mm SL, of which nine were x-rayed, and eight additional, non-type specimens that were only x-rayed for osteological comparison; meristic character values are presented as median and value range for specimens, holotype indicated by * and placed in brackets if different to median or not within range. See Table 4 for frequency distributions of variable meristic characters, and Tables 5–6 for summaries of all meristic and morphometric variation, respectively. Dorsal fin spines XIII* (XII–XIII), rays 9* (9–10); anal fin spines III*, rays 8 (7*–9); caudal fin rays 10+8+7+10 (9–10+8+7+8–10, n=15); pectoral fin rays 15 (13–16) [14*]; pelvic spines I*, rays 5*; vertebrae 10*+15*=25* (n=15); lateral line scales 37* (34–40); scales above lateral line 7* (6–7); scales below lateral line 11* (11–12); pre-dorsal scales 11* (10–13); cheek scale rows 5* (4–6); caudal circumpeduncular scales 18 (16–19*); gill rakers on first arch 9*+16*=25* (8–10+15–16=23–26); opercular spines 2*; preopercular spines 19* (16–27).

Dorsal profile straight, 45° to horizontal, from snout to occiput, slightly raised as a hump (convex) on posterior end of nape, continuing straight or slightly concave to base of last dorsal-fin ray, then straight (horizontally) to caudal fin base. Ventral profile almost evenly arched: straight or slightly convex at 35° to the horizontal plane from snout to pelvic fin base, slightly concave to base of last anal-fin ray, then straight (horizontally) to caudal fin base. Lateral line complete, approximately parallel to dorsal profile. Body depth at dorsal fin origin 35.9 (33.5–39.8) % SL; body depth at anal fin origin 30.4 (27.8–34.2) % SL; caudal peduncle length 17.7 (14.2–19.2) % SL; caudal peduncle depth 11.5 (7.5–13.3) % SL; pre-anus length 64.2 (59.1–66.4) % SL. Head length 34.7 (32.6–36.8) % SL; head pointed; snout length 39.3 (36.0–44.6) % HL; upper-jaw length 31.5 (26.2–36.3) % HL, jaws equal; jaw width 33.0 (28.6–37.6) % HL. Mouth terminal, gape oblique. Maxillary reaching to vertical through posterior nostril.

Jaws with outer row of large, conical teeth of same size, with 4 (4–5) [5*] rows of smaller teeth, embedded in a sturdy gum; teeth absent on vomer and palatines. Teeth in outer row of upper jaw 37.5 (32–53) [44*], number increasing with size of fish, 4.4 (2.2*–7.3)/mm when standardised with lower jaw length; teeth on outer row of lower jaw 38* (35–49), number only increasing slightly with size of fish, 4.6 (1.9*–7.8)/mm when standardised with lower jaw length. Nostrils wide apart; separated by a distance equal to 0.5 eye diameter. Lower jaw U-shaped when viewed from below; upper jaw usually with fleshy, narrow, discontinuous lip fold, occasionally continuous. Eye diameter 27.3 (20.9–31.1) % HL; inter-orbital width 24.6 (20.5–28.7) % HL; interorbital region smooth, with slightly elevated bony ridge above each orbit; postorbital length 36.9 (35.1–40.8) % HL. Lacrimal with 4–6 serrations along posteroventral edge, overhung by skin. Preoperculum with 19 (16–27) [18*] spines, longest and most robust on apex, reduced in size dorsally and anteriorly, anteriormost spine situated behind posterior edge of orbit. Lower opercular spine longer and more robust than upper one, not extending beyond edge of opercular lobe. Posttemporal not exposed, covered with skin and scales; cleithrum exposed on posterior edge, covered with skin and scales elsewhere, serrate posteriorly; supracleithrum covered by a thin layer of skin.

Dorsal fin origin vertically above pelvic fin origin, posterior to vertical plane through pectoral fin origin; predorsal length 45.4 (43.5–47.4) % SL. Dorsal fin base with 1 sheath scale, length 0.2 (47.0–52.3) % SL, fin length 57.5 (52.7–60.5) % SL, spinous dorsal arched; 5 th (4 th– 6 th) spine longest, length 16.8 (13.6–19.5) % SL, spines progressively shorter from first and last respectively; last dorsal fin spine joined to first dorsal fin ray by membrane; 2 nd (2 nd– 3 rd) dorsal fin ray longest, length 15 (12.7–18) % SL; margin of rayed portion rounded to tip of last ray. Anal fin origin immediately anterior to vertical through base of last dorsal fin spine, terminating just anterior to vertical through base of last dorsal fin ray; pre-anal fin length 64.2 (59.1–66.4) % SL. Anal fin base with 2 sheath scales, length 16.1 (14–17.7) % SL, fin length 23.8 (20.7–25.8) % SL; 2 nd anal fin spine longest, length 14.5 (11.4–17.2) % SL; 1 st (1 st– 2 nd) anal fin ray longest, length 16.3 (14.9–17.1) % SL; subsequent rays progressively shorter; distal margin of rayed portion rounded.

Caudal fin slightly forked, upper caudal-fin lobe length 26.9 (24.0–30.0) % SL; median caudal ray length 19.5 (16.3–21.4) % SL. Pre-pectoral fin length 33.2 (30.8–37.9) % SL, pectoral fin length 21.7 (19.8–23.8) % SL. Prepelvic fin length 39.9 (37.4–45.2) % SL, pelvic fin spine length 13.4 (11.2–18.9) % SL; 1 st (1 st– 2 nd) pelvic-fin ray longest, length 23.1 (21.1–25.8) % SL; pelvic fin length 24.0 (22.0–26.1) % SL.

Colouration when fresh: Top of head, from tip of snout to insertion of first scale row, dark orange.A horizontal silvery-gold band of pigmentation from posterior of lacrimal around ventral and posterior borders of orbit to level of dorsal edge of eye. Overall body colour silvery-gold dorsally, fading to silver below. Each scale above scale row running through base of pectoral fin edged with dark orange pigmentation; intensity of pigmentation increasing dorsally. Dorsal fins dusky orange overall with dark outer margin; outer rays of soft dorsal whitish-grey. Caudal fin dusky orange overall with dark outer margin; outer rays of soft dorsal whitish-grey; dark blotch sometimes present on lower lobe, more prominent in juveniles. Anal fin dusky orange overall; whitish-grey blotch on posterior rays. Pelvic fin dusky orange overall; whitish-grey outer margin. Pectoral fins dark at base, overall dusky with increasing orange-brown colouration to ray margins dorsally ( Fig. 5b ).

Colouration when preserved: Uniformly dark brown to black dorsally, becoming lighter ventrally. Lateral line pale in colouration. Fins uniformly dark brown to black; white blotch present at posterior base of anal fin. Each scale above scale row running through base of pectoral fin edged with dark pigmentation ( Fig. 5a )

Distribution: The species is presently known to occur in the Prince Regent and Roe river catchments that drain northwest from the Kimberley Plateau ( Fig. 6 ).

Etymology: The specific name wintoni is in honour of Western Australian author and Kimberley conservationist Tim Winton, whose many novels espouse a love of fish and the Australian landscape.

Ecology: This species is found in clear waters, over sandy to rocky substrates, with larger adults found in deeper (> 2 m), slow to moderate flowing areas around large boulders or holding position in the centre of stream flow ( Fig. 7 ). Juveniles are more common in moderately deep and shallow runs, darting between the cover of rocks and woody debris. Some stomachs were examined, and the contents indicated an omnivorous diet consisting mainly of insect larvae, terrestrial insects and crustaceans.

Remarks: In Shelley et al. (2018a), gill rakers on the upper limb of the first gill arch and scale rows above the lateral line were presented as distinguishing characters between the Hannia species based on preliminary analysis. However, following further data collection and analysis, these characters were found to be uninformative.

Figures

FIGURE 1. Distribution of Hannia (white circles) based on all known records.

FIGURE 5. Hannia wintoni sp. nov., WAM P.35010-001, holotype, 166 mm SL, unnamed creek flowing into lower Prince Regent River, Western Australia: (a) preserved and (b) alive (image laterally inverted).

FIGURE 6. Distribution of Hannia wintoni sp. nov. (squares) and H. greenwayi (circles) based on all known records. Sites from which specimens were examined in this paper are marked with a red outline.

FIGURE 7. A site on the upper Prince Regent River occupied by Hannia wintoni sp. nov. This is typical sandstone-based, slow to moderate-flowing habitat present throughout the Roe and Prince Regent rivers, Western Australia, preferred by the species.