Thymichthys verrucosus (McCulloch & Waite) Last & Gledhill Csiro, 2009

Last, Peter R. & Gledhill Csiro, Daniel C., 2009, A revision of the Australian handfishes (Lophiiformes: Brachionichthyidae), with descriptions of three new genera and nine new species 2252, Zootaxa 2252 (1), pp. 1-77 : 65-72

Thymichthys verrucosus (McCulloch & Waite) , new combination

Figs 2 , 5 , 6 , 23, 26, 27; Tables 6 – 10

Sympterichthys verrucosus McCulloch & Waite, 1918: 76–77 , pl. 7 (3) [original description].

Brachionichthys verrucosus: Scott, 1953: 159 [new combination].

Brachionichthys sp. 3 : Last, Scott & Talbot, 1983: 253, fig. 22.5.

Holotype. SAMA F 626 , ca. 31.5 mm SL (caudal fin broken off near its base), St Vincent Gulf , South Australia, ca. 34° 53'S, 138° 06'E, no other data.

Paratype. SAMA F 627 , 28.6 mm SL, same data as holotype .

Additional material. 49 specimens (5–67 mm SL): AMS IA 3604, ca. 58 mm SL (damaged), south of Montague Island , New South Wales, ca. 36° S, 150° E, 1928; CSIRO H 796–01 , 40.5 mm SL, Ringarooma Bay , Tasmania, 40° 50'S, 147° 49'E, 29–30 m, 21 Jul. 1987; CSIRO H 974–03 , 60.5 mm SL, Tasmania, no other data; CSIRO H 3781–01 , 63.5 mm SL, north-east of Eden , New South Wales, 36° 58'S, 150° 12'E, 115– 117 m, 4 Sep. 1994; CSIRO H 3792–03 , 34.9 mm SL, south-east of Lakes Entrance, Bass Strait , Victoria, 38° 36'S, 148° 33'E, 125 m, 27 Aug. 1994; CSIRO H 3792–04 , 62.3 mm SL, south-east of Lakes Entrance, Bass Strait , Victoria, 38° 36'S, 148° 33'E, 125 m, 27 Aug. 1994; CSIRO H 3795–01 , 49.9 mm SL, south-east of Gabo Island , Victoria, 37° 43'S, 150° 05'E, 136 m, 16 Sep. 1994; CSIRO H 4119–01 , 36.4 mm SL, east of Maria Island , Tasmania, 42° 43'S, 148° 24'E, 87–152 m, 5 Nov. 1984; CSIRO H 4267–01 , 47.8 mm SL, south of Green Cape , New South Wales, 37° 19'S, 150° 04'E, 82 m, 6 May 1996; CSIRO H 4451–01 , 53.1 mm SL, east of Disaster Bay , New South Wales, 37° 18'S, 150° 17'E, 125 m, 7 Dec. 1996; CSIRO H 4452–01 , 45.3 mm SL, south-west of Cape Everard , Victoria, 38° 03'S, 149° 07'E, 112–115 m, 25 Nov. 1996; CSIRO H 4453–01 , 45.1 mm SL, CSIRO H 4453–02 , 44.9 mm SL, CSIRO H 4453–03 , 67.1 mm SL, CSIRO H 4453– 04 , 52.8 mm SL, and CSIRO H 4453–05 , 61.0 mm SL, east of Bermagui , New South Wales, 36° 30'S, 150° 18'E, 214–225 m, 1 Dec. 1996; CSIRO H 5311–01 , 57.5 mm SL, south-west of Cape Everard , Victoria, 37° 57'S, 149° 16'E, 111–113 m, 24 Apr. 2000; CSIRO T 1 , 54.1 mm SL, Frederick Henry Bay , Tasmania, ca. 42° 55'S, 147° 36'E, 1 Jun. 1905; CSIRO T 5 , 4 specimens, 48.1–61.6 mm SL, east of Flinders Island, Bass Strait , Tasmania, 40° 00'S, 148° 47'E, 20 m, 13 Apr. 1985; CSIRO T 9 , 2 specimens, 34.5–49.8 mm SL, east of Flinders Island, Bass Strait , Tasmania, 40° 00'S, 148° 47'E, 4 Jun. 1905; NMV A 2629 , 41.1 mm SL, off Lakes Entrance, Bass Strait , Victoria, 38° 54'S, 147° 55'E, 71 m, 17 Nov. 1981; NMV A 3040 , 57.4 mm SL, 22 km south-east of Point Hicks , Victoria, 38° 01'S, 149° 10'E, 115 m, 30 Jun. 1982; NMV A 13022 , 2 specimens, 39.7 and 48.7 mm SL, south-east of Merimbula , New South Wales, 36° 53'S, 150° 12'E, 117–119 m, 5 Aug. 1993; NMV A 29405–001 , 2 specimens, 51.8–53.7 mm SL, off Marlo, Bass Strait , Victoria, 38° 27'S, 148° 26'E, 226 m, 10 Sep. 1984; NMV A 29408–002 , 61.8 mm SL, off Cape Conran, Bass Strait , Victoria, 38° 00'S, 148° 09'E, 118 m, 22 Sep. 1983; NMV A 29409–002 , 44.7 mm SL, off Marlo, Bass Strait , Victoria, 38° 33'S, 148° 24'E, 218–221 m, 6 Jun. 1984; NMV A 29409–003 , 51.0 mm SL, off Marlo, Bass Strait , Victoria, 38° 33'S, 148° 24'E, 218 m, 6 Jun. 1984; NMV A 29413–001 , 60.7 mm SL, off Lakes Entrance, Bass Strait , Victoria, 38° 10'S, 148° 32'E, 76 m, 7 Jun. 1982; NMV A 29414–001 , 54.3 mm SL, off Lakes Entrance, Bass Strait , Victoria, 38° 51'S, 148° 8'E, 78 m, 10 Sep. 1983; NMV A 3040 , 57.0 mm SL, off Cape Conran, Bass Strait , Victoria, 38° 02'S, 149° 10'E, 114 m, 30 Jun. 1982; NMV A 4268 , 3 specimens, 5.4–16.9 mm SL, east of Maria Island , Tasmania, 42° 37'S, 148° 13'E, 100 m, 23 Apr. 1985; SAMA F 668 , 3 specimens, 29.9–41.5 mm SL, east of Glenelg, Gulf St Vincent , South Australia, 34° 34'S, 138° 19'E, no other data; SAMA F 4750 , 52.5 mm SL, Venus Bay, western Eyre Peninsula , South Australia, ca. 33° 12'S, 134° 40'E, Aug. 1983; SAMA F 10458 , 57.0 mm SL, and SAMA F 10459 , 54.8 mm SL, Venus Bay, western Eyre Peninsula , South Australia, ca. 33° 12'S, 134° 40'E, 37–55m, Jul. 1982; SAMA F 11927 , 40.3 mm SL, off Wilson Bluff, Great Australian Bight , South Australia, 33° 20'S, 130° 12'E, 196 m, 3 Aug. 1981; SAMA F 11928 , 59.4 mm SL, Venus Bay, western Eyre Peninsula , South Australia, ca. 33° 12'S, 134° 40'E, 32–45 m, 1 Jun. 1982; SAMA F 11929 , 53.7 mm SL, Venus Bay, western Eyre Peninsula , South Australia, 33° 12'S, 134° 40'E, 1 Aug. 1982; TMH D 928 , 28.1 mm SL, off Bridport, Bass Strait , Tasmania, ca. 40° 57'S, 147° 26'E, 15 Oct. 1950 .

Diagnosis. Member of the genus Thymichthys with a combination of the following characters: esca variable in size, length 23–57% (mean 37%) of illicium length (including esca); illicium short to moderately elongate, not thick and fleshy, without dermal spinules, length 15–27% SL, 1.9–3.4 times in head length, its base adjacent upper jaw (pre-illicial length 1.2–3.2% SL); eye small, diameter 4.8–7.1 times in head length; body usually densely covered with prominent, close-set, globular or fleshy warts; skin with small, widely spaced, embedded, spiny scales and variably developed dermal flaps; spinules unicuspid or bicuspid, prostrate, their tips embedded or barely visible); second dorsal-fin rays 14–18 (mainly 16–17), fin base length 60–73 (mean 66)% SL; length of second dorsal-fin spine 1.1–1.6 times length of longest ray of second dorsal fin; 6–9 anal-fin rays; usually 8 pectoral-fin rays; body brownish with lighter and darker blotches and spots; presence of blackish bar on caudal peduncle and caudal-fin base that extends onto hind parts of dorsal and anal fins.

Description. Based on tasselled form (types damaged); morphometric data based on tasselled form, data for eastern form in parentheses (see also remarks below); meristic data for types given first followed by data for other material.

D 1 holotype 2, paratype 2 (2, n=34); D2 14, 14 (15–18, rarely 15 or 18); A 6, 6 (7–9, rarely 9); Pc damaged, possibly 7–8 (7–10, usually 8); Pv i 4, i 4 (i 4); C damaged, 1 (1) + damaged, 7? (6–7, rarely 7) + damaged, 1? (1–2, rarely 1) = 9, 9 (9); Vt 10, 9 (9–11, mainly 10) + 10, 11 (11–13, rarely 13) = 20, 20 (21–23, rarely 23).

Body relatively short, usually robust anteriorly; upper anterior margin strongly convex and elevated; profile truncate to weakly convex above mouth (pre-illicial snout almost vertical); margin below first dorsal fin almost straight, with a broad supraocular shelf, usually with a notch above posterior eye; upper eye well separated from dorsal margin; nape variably humped; profile subtriangular to compressed slightly when viewed anteriorly; anterior ventral profile convex, more flattened between pelvic fins; abdomen little to slightly expanded; caudal peduncle short, length 3.5–5.1 (3.4–8.7)% SL. Head length 49–53 (49–56)% SL; snout short, length 5.1–6.1 (5.1–7.1) times in head; eye small, diameter 4.8–6.1 (4.9–7.1) times in head length; gill opening large, tubiform, aperture slightly smaller than eye; prominent, protruding from head; skin smooth and distinct from warty skin adjacent; located above insertion of pectoral fin. Nostrils small, obscure, usually indistinct from surrounding pores of the cephalic sensory system; apertures small, well separated (anterior opening about half way between upper jaw and posterior opening); anterior opening usually short, tubular and fringed distally; posterior opening short, tubular (pore-like), located well away from orbit, near horizontal level of ventral aspect of eye and dorsally or posterodorsally to anterior opening. Mouth variable, small to moderate in size, terminal, not protractile; upper jaw slightly oblique, 3.2–3.6 (2.8–3.6) in head; lips narrow, fleshy, partly recessed into well-developed, circumoral groove; angle of jaw retracting into groove below anterior half of eye; tongue well developed, rounded apically. Teeth small, villiform, in narrow bands in both jaws; band in lower jaw broader near symphysis than in upper jaw (mouth not dissected).

Skin thick, flabby, very corrugated; body densely covered over most of surface with small to large (possibly smaller or indistinct in some specimens due to preservation), wart-like protuberances; warts very close set, globular apically in best preserved material; rarely terminating posteriorly in a protruding spinule. Body scales variably developed, sparse, usually densest on head, patchy and widely separated on tail, absent ventrally on belly; their bases variable in shape, deeply embedded; narrow monospinulate or bicuspid with very short, barely emergent tips; spinules originating at posterior margin of scale base, tips directed obliquely, posteriorly on tail, often more dorsally on head. Small to large dermal flap usually present on mid-arm of pectoral fin; flap thallate, irregular in shape, simple or complex, subequal in size to gill opening in some specimens; dermal filaments present over most of head and body, their length and shape variable. Fin spines and rays and their associated membranes without visible spines (sometimes sparse, minute, embedded as evident from radiographs), instead covered with small warts and dermal filaments (densest basally); fin membranes thick, fleshy; illicium naked, covered with thick, almost smooth, fleshy skin. Scales of acousticolateralis system bicuspid, with small, oval central pore flanked by slender apical spinules; spinules almost Ushaped, much longer than spinules of body scales; arranged in well defined series; most pronounced on head (below lower jaw, below and above eye, and on operculum and nape) and as a single row extending along mid-upper trunk more or less parallel to dorsal margin to caudal-fin base.

Illicium terminal on snout; its base adjacent upper jaw and almost confluent with origin of first dorsal fin; moderately elongate, length 1.9–2.6 (2.1–3.4) times in head length, 1.2–1.5 (1.2–1.7) times in length of second dorsal-fin spine; apex of depressed esca reaching to slightly behind base of third dorsal-fin spine; illicium retractable into a narrow, fleshy groove beside first dorsal fin (groove usually present only on one side of head, no obvious preference for either side); esca of moderate size, with short, slender or narrowly thallate filaments, its length 1.9–3.1 (1.7–4.4) times in length of illicium; filaments dense, almost straight to twisted slightly; illicial base distinct, expanded slightly but not obscured by skin. First dorsal fin not greatly elevated, its base long; second dorsal-fin spine almost straight to recurved slightly, originating adjacent base of illicium, slightly longer than third spine; membrane of fin terminating above or slightly behind pelvic-fin base; first dorsal-fin base 2.1–2.3 (2.1–2.9) times in second dorsal-fin base. Second dorsal fin rays not elevated anteriorly; fin margin not indented, almost straight to weakly convex, barely decreasing in height posteriorly, last few posterior rays smallest; rays simple; fin base elongate, 67–73 (60–73)% SL; longest ray of second dorsal fin 1.2–1.5 (1.1–1.6) times in longest dorsal-fin spine; fin membrane relatively thick, partly concealing bases of fin rays. Anal-fin moderately tall, penultimate posterior rays subequal to those anteriorly; length of anal-fin base 2.0–2.3 (1.9–2.3) times in second dorsal-fin base. Pectoral fin strongly arm-like, radials elongate, robust, extending posteriorly for up to an eye diameter behind gill opening; fin rays weakly filamentous distally, short, membranes deeply incised, slightly more so posteriorly, tips flexible. Pelvic fin well developed, robust; rays thick and fleshy, rather deeply incised; anterior spine short, embedded and indistinct; fin located on ventral surface, directed ventrolaterally or posteroventrally, base aligned horizontally; interpelvic space broad, flat to weakly concave. Caudal fin moderately elongate, narrowly rounded to emarginate; length 2.8–4.3 (3.0–4.8) times caudal peduncle depth.

Coloration. McCulloch and Waite (1918) describe the alcohol preserved holotype as ‘brownish with lighter and darker areas; a large whitish blotch above the gill opening and another above the anterior dorsal rays; indefinite dark markings on the head below the eye, on the anterior portion of the back, and covering the abdomen; first dorsal with a dark basal spot, and a larger one on its upper third; an oblique dark marking covers the base of the tail, the posterior dorsal rays, and all the anal fin; distal portions of the caudal and pectoral fins blackish.’ The holotype and paratype, which are now uniformly dark brown and appear to have been dehydrated at some stage (shrunken and brittle), are not useful for describing its colour. However, material examined indicated that this species is highly variable in coloration but there are some consistent features that were noted above. These include: body brownish with lighter and darker blotches and/or spots and the presence of a blackish bar on the caudal peduncle and caudal-fin base extending onto the hind parts of dorsal and anal fins (persistent in old preserved material). Also, the outer margins of the pectoral and caudal fins are often blackish, and the entire outer half of the anal fin is black in some specimens. Some specimens have small brownish black spots on the fins and ventral head (e.g. CSIRO H 4453–03, Fig. 27A ), and are covered dorsally with a distinct network pattern (e.g. CSIRO H 4453–04, Fig. 27B ), or a more simple pattern of dark markings (e.g. CSIRO H 5311–01, Fig. 27C ). Fresh coloration: light and dark areas and markings more obvious than in preserved material.

Size. Attains at least 67 mm SL and ca. 93 mm TL. The holotype, which is damaged with the caudal fin separated at the peduncle, is now about 31.5 mm SL and 40 mm TL (including the tail fragment). The paratype is intact and is 28.6 mm SL and about 37 mm TL. Both specimens are strongly dehydrated and much shorter than the manuscript lengths of 45 mm and 41 mm (presumed TL but not stated in McCulloch and Waite’s manuscript) respectively. Several specimens are gravid, including the paratype; other gravid females ranged from 40.5–60.5 mm SL (n=12). Egg capsule diameter ranged from ca. 1.6–3.2 mm and the eggs are slightly smaller, 1.5–2 mm diameter.

Distribution. The type material was collected in St Vincent Gulf, South Australia (ca. 34° 53'S, 138° 06'E). Comparative material was collected off Wilson Bluff, central Great Australian Bight (33° 20'S, 130° 12'E), eastward to off Bermagui in southern New South Wales, and southward through Bass Strait to Frederick Henry Bay, southeastern Tasmania (ca. 42° 55'S, 147° 36'E); depth to about 230 m.

Etymology. The epithet is presumably based on the Latin verrucosus (full of warts) with reference to the obvious warty nature of its skin. Initially referred to in the vernacular as the Warty Handfish (Whitley, 1949) and retained as such as the Australian Standard Name (Yearsley et al., 2006).

Comparisons. Thymichthys verrucosus differs from its congener, T. politus , in some meristic values, coloration, morphology of the skin and illicium, and in several morphometric features. The morphs of Thymichthys verrucosus have a relatively longer (15–27% vs. 14–17% SL in T. politus ) and more slender illicium with a proportionally smaller esca; the illicium is also located closer to the upper jaw (pre-illicial distance 1.2–3.2 vs. 3.3–7.9% SL). These species differ in colour with T. verrucosus being primarily brownish on the body with lighter and darker blotches and spots, and has a blackish bar on the caudal peduncle and caudal-fin base that extends onto the hind parts of dorsal and anal fins. In T. politus the body is reddish or pinkish and there is no equivalent dark band near the caudal base. Thymichthys verrucosus has more prominent, wart-like structures on the skin (usually globular rather than flattened) and dermal flaps, particularly those on the arm of pectoral fin, nape and sides of tail, are much better developed (dermal flaps usually rudimentary or absent in T. politus ).

The morphs of Thymichthys verrucosus also have a more robust body with larger proportions around the head than T. politus : eye diameter 7.3–11 vs. 5.6–6.7% SL; and maxillary length 14–18 vs. 11–13% SL. Other differences include: length of second dorsal fin spine 25–37 vs. 19–24% SL in T. politus ; anal-fin base (28–36 vs. 37–42% SL); length of longest dorsal-fin spine 1.1–1.6 vs. 0.7–1.0 times length of longest ray of second dorsal fin. Thymichthys verrucosus has fewer anal-fin (usually 7–8 vs. 9–10) and typically fewer pectoral-fin rays (usually 8 vs. 9–10).

Remarks. Thymichthys verrucosus is represented in collections (n=51) by at least four morphs and may represent an unresolved species complex. These forms all have warty skin, a brownish mottled colour pattern with a blackish bar through the posterior tail and caudal fin which is unique to T. verrucosus . However, meristic ranges were atypically broad for these specimens, and there appear to be differences in body shape, skin morphology, colour, illicium shape, and size at maturity. The holotype and paratype differ from all other material in having unusually low second dorsal (14 in both types vs. 15 – 18 rays, only one of 35 specimens had 15 rays), anal (6 in both types vs. 7 – 9 rays) and vertebral (20 in both types vs. 21 – 23 rays) counts. The paratype, a gravid female, was only 28.6 mm SL which was much smaller than the next smallest female with an obvious egg mass (CSIRO H 796 – 01, 40.5 mm SL). Otherwise, an illustration of the holotype resembles specimens of the tasselled form (on which the description above is based) in having prominent warty skin and very well-developed dermal flaps and filaments; both types are now badly desiccated and very fragile, so coloration and details of skin texture could not be determined. However, the above characters are clearly evident from McCulloch and Waite’s original description and drawing. Ranges of these forms overlap but there is no evidence to suggest they are sympatric; the ornate tasselled form occurs from the Great Australian Bight (off South Australia), through Bass Strait, to Tasmania, whereas both types were collected in Gulf St Vincent (South Australia). Given the poor state of preservation of types it was not possible to obtain useful morphometric data for comparison; consequently, we were unable to obtain additional characters to shed light on their taxonomic status.

The other two morphs are included mainly in material collected further east: a bulbous headed, slightly compressed form distributed from the Great Australian Bight to Lakes Entrance, eastern Victoria, and a compressed, non-bulbous headed form found off eastern Victoria and southern New South Wales. There are minor differences between these forms in coloration, esca size, wartiness of the skin, spinule exposure and density, thickness of fin membranes, abdomen extension, and tail depth and elongation. Some of these variations may be linked to general variability in body shape of soft-bodied fishes and others to artefacts of preservation. However, some of these differences seem to be consistent within regions providing evidence of either population or species structure. The forms have been combined in this study pending the collection of more material (particularly from the type locality), and a comprehensive molecular study. The Barcode of Life Project for fishes (FISHBOL), using the CO1 gene, has successfully discriminated several species of handfishes (Last et al., 2007; Holmes, unpublished data) and should shed light on their relationships.

Figures

FIGURE 2. Illustrations of the illicium and esca of: A. Brachionichthys australis, CSIRO H 4114–07, 55.8 mm SL; B. Brachionichthys hirsutus, CSIRO T 7, 78.9 mm SL; C. Brachiopsilus dianthus sp. nov., CSIRO H 4995–01, holotype, 99.5 mm SL; D. Brachiopsilus dossenus sp. nov., NMV A 29405–002, holotype, 65.0 mm SL; E. Brachiopsilus ziebelli sp. nov., CSIRO T 1993–01, holotype, 101.5 mm SL; F. Pezichthys amplispinus sp. nov., CSIRO H 4460–01, 37.2 mm SL; G. Pezichthys compressus sp. nov., CSIRO H 4447–01, holotype, 42.4 mm SL; H. Pezichthys eltanini sp. nov., LACM 11516–1, holotype, 30.0 mm SL; I. Pezichthys macropinnis sp. nov., CSIRO H 5317–02, holotype, 20.5 mm SL; J. Pezichthys nigrocilium sp. nov., CSIRO H 6154–01, holotype, 40.8 mm SL; K. Sympterichthys moultoni sp. nov., CSIRO H 3773–03, holotype, 45.1 mm SL; L. Thymichthys politus, CSIRO H 782–01, 67.3 mm SL; M. Thymichthys verrucosus (tasselled morph), CSIRO T 5, 51.3 mm SL; and N. Thymichthys verrucosus (eastern form) CSIRO H 3781– 01, 63.5 mm SL.

FIGURE 5. Skin morphology of: A. Thymichthys politus, CSIRO H 782–01 (x50); B. Thymichthys verrucosus, SAMA F 4750 (x40), showing a dermal flap. All images orientated as a view of mid-upper body on left side (i.e. anterior part to left).

FIGURE 6. Underwater images of live handfishes (photographer K. Gowlett-Holmes): A. Brachiopsilus ziebelli sp. nov. (Loney’s morph) with egg mass, Waterfall Bay, Tasmania, not retained; B. Brachionichthys hirsutus, Derwent Estuary, Tasmania, not retained; C. Thymichthys politus, Primrose Bay, Tasmania, not retained; D. Thymichthys verrucosus (tasselled morph), habitat artificial, Tasmania; E. Brachiopsilus dianthus sp. nov., CSIRO 4995–01, holotype, 99.5 mm SL, habitat artificial, Tasmania; F. Sympterichthys moultoni sp. nov., CSIRO H 4461–01, paratype, 39.3 mm SL, habitat artificial, Tasmania.

FIGURE 27. Variation in coloration in Thymichthys verrucosus: A. CSIRO H 4453–03, 67.1 mm SL, ‘spotted’ morph; B. CSIRO H 4453–04, 52.8 mm SL, ‘network’ morph; and C. CSIRO H 5311–01, 57.5 mm SL, ‘plain’ morph.