Barryichthys hutchinsi, Conway, Kevin W., Moore, Glenn I. & Summers, Adam P., 2019

Conway, Kevin W., Moore, Glenn I. & Summers, Adam P., 2019, A new genus and two new species of miniature clingfishes from temperate southern Australia (Teleostei, Gobiesocidae), ZooKeys 864, pp. 35-65 : 35

Barryichthys hutchinsi sp. nov. Figs 2A, 3 A–C, 4A, 5A, 6, 7, 8, 9A, C–E, 10

Common name: Brown rat clingfish

Genus B sp. Hutchins 2008: 725.

Holotype.

WAM P.28981-004 , male, 15.4 mm SL; Western Australia, Cottesloe Reef platform, Perth (31°59'00.0"S, 115°45'00.0"E), 16 January 1986, J. Keesing et al., CT scan: https://doi.org/10.17602/M2/M78748.

Paratypes.

Western Australia: WAM P.28981-003, 4 , 16.0-16.9 mm SL; same data as holotype. - WAM P.34510-001, 5 (2 C&S), 14.2-16.3 mm SL; Western Australia, Cottesloe Reef platform, Perth (31°58'59"S, 115°45'00"E), 29 January 1985, J. Keesing. - WAM P. 34940-001, 1, female , 18.7 mm SL; Trigg Reef platform, Perth (31°52'46.5"S, 115°45'04.7"E), 13 January 1986, J. Keesing et al.

Other material.

South Australia: AMS I.20171-012, 6 (2 C&S), 12.4-13.1 mm SL (immature); South Australia; Kangraoo Island, Vivonne Bay (36°00'00.0"S, 137°10'48.0"E), D. Hoese & K. Handley. - AMS I.49000-001, 2 (1 CThttps://doi.org/10.17602/M2/M80016), 14.0-14.6 mm SL; Victor Harbor, Bluff Jetty (35°35'19.1"S, 138°36'16.5"E), 25 March 2015, G. Short.

Diagnosis.

Barryichthys hutchinsi is distinguished from B. algicola (below) by a shorter, deeper body (body depth at dorsal-fin origin 10-11% SL vs. 7-8% SL), a wider, deeper head (head width at widest point 66-75% HL vs. 55-61%; depth at orbit 30-32% HL vs. 27-29%; interorbital width 27-33% HL vs. 20-24%), ventral margin of the orbit obscured by cheek in ventral view (vs. entire ventral margin of orbit visible in ventral view), by having a shorter abdominal region with fewer vertebrae (abdominal vertebrae 17 vs. 21) and fewer ribs (11-12 vs. 15), fewer epicentrals (14-15 vs. 18-19), and a lower total number of vertebrae (total number of vertebrae 38-39 vs. 42-44), and by features of live colour pattern, including body background colour golden-yellow to olive-brown (vs. uniform green), the presence (vs. absence) of a variable number of irregularly shaped light to dark brown markings along dorsal midline, and the presence (vs. absence) of a series of light to dark brown elongate lateral markings forming an incomplete or complete horizontal stripe.

Description.

General body shape as in Figs 2A, 3 A–C. Select morphometric and meristic characters are listed in Tables 1, 2. Largest specimen examined 18.7 mm SL. Body moderately elongate, circular in cross-section anteriorly, becoming increasingly laterally compressed posteriorly. Widest point of body midway between head and dorsal-fin origin, corresponding with centre of abdominal cavity. Body width and depth tapering gradually posteriorly from widest point. Caudal peduncle thin, elongate (approximately 1/5 of SL). Head relatively large (approximately 1/3 of SL), slightly dorsoventrally compressed anteriorly, becoming increasingly circular in cross-section posteriorly. Widest point of head midway between orbit and opercular opening; wider than widest point of body. Eye large, positioned on dorsolateral surface of head; ventral margin of orbit not visible in ventral view (Fig. 5A). Snout of moderate length, triangular, narrowest anteriorly. Anterior nostril a small tubular opening (Fig. 5A). Posterior nostril surrounded by a low fleshy rim; situated along anterodorsal margin of orbit (Fig. 5A). Gill membranes united across midline, free from isthmus.

Mouth subterminal, small; posterior tip of upper jaw not reaching imaginary vertical line through anterior margin of orbit when mouth closed. Articulation between anguloarticular and quadrate located directly along imaginary vertical line through anterior margin of orbit. Upper lip fleshy (Fig. 5A); in dorsal view appearing uniform in thickness around entire anterior margin of snout; in lateral and ventral view upper lip appearing markedly thicker anteriorly, tapering in thickness posteriorly. Lower lip restricted to lateral margin of lower jaw only; separated along ventral midline by a fleshy pad of skin at symphysis of lower jaw. Lower lip narrower than upper lip, with poorly developed skin flap anteromedially. Fleshy pad of skin at symphysis of lower jaw bordered anterolaterally by a shallow groove; confluent posteriorly with skin of isthmus (Fig. 5A). Upper jaw longer and wider than lower jaw (Fig. 7A), creating a narrow gap between teeth of upper and lower jaw when jaws closed. Premaxilla with an outer row of 6-8 small conical teeth with slightly recurved tips, arranged along anteromedial edge, adjacent to symphysis, and a small patch of 2-4 tiny conical teeth on lingual surface posterior to teeth of outer row. Dentary with a single row of 5-6 conical teeth; anteriormost 3-4 teeth dagger-like, only slightly recurved and orientated at a 180° angle to dentary, with cusp directed anteriorly; posteriormost 2-3 teeth strongly recurved and orientated at a 90° angle to dentary, with cusp directed posterodorsally (Fig. 7A). Teeth on dentary slightly larger than largest teeth on premaxilla. Ascending process of premaxilla narrow, elongate (Fig. 7A); extending posteriorly along dorsal surface of neurocranium to a point slightly anterior to epiphyseal commissure of supraorbital lateral line canal when jaws closed. Pharyngeal jaws comprising patch of 3-4 tiny conical teeth with slightly recurved tips on pharyngobranchial 3 toothplate only (Fig. 7C); teeth absent from ceratobranchial 5 (Fig. 7B). 3-5 tiny, gnarled gill rakers along anterior and posterior edge of ceratobranchials 2-3 and anterior edge of ceratobranchial 4; ceratobranchial 1 without gill rakers (one gill raker along posterior edge of ceratobranchial 1 of left side only in one C&S specimen). Gill filaments associated with gill arches I–III only (three gill filaments of Briggs, 1955); restricted to lower (ceratobranchial) portion of gill arches only; ceratobranchial 2 and 3 with paired rows of filaments (holobranch); ceratobranchial 1 with single row (hemibranch) of 4-5 poorly developed gill filaments. Basihyal a short club-like element; capped with cartilage anteriorly (Fig. 7B). Ceratobranchials 1-4 rod-like elements; ceratobranchial 5 a short plate-like element, wider and shorter than more anterior ceratobranchial elements (Fig. 7B). Epibranchials 1-2 short rod-like elements; epibranchial 3 a club-like element, broadest anteriorly; epibranchial 4 a single splint like element (epibranchial 4 fused to epibranchial 3 on left side only in one C&S specimen; Fig. 7C). Five or six branchiostegal rays (Fig. 7D). In specimens with five, first ray articulating medially with hyoid bar along anterior ceratohyal; posterior rays articulating with hyoid bar laterally, including two along posteriormost part of anterior ceratohyal, one straddling junction between anterior and posterior ceratohyals, and one along anteriormost part of posterior ceratohyal. In specimens with six, an additional small ray without contact to hyoid bar located anterior to ray articulating with medial face of hyoid bar.

Superficial neuromasts on surface of head not observed in material other than a pair of large superficial neuromasts housed within a pair of shallow depressions at centre of symphysial pad on lower jaw. Cephalic lateral-line system comprising supraorbital lateral-line canal only; 2 nasal pores; 1 postorbital pore. Canal pores minute; flush with surface of skin and difficult to locate. Supraorbital lateral line canals connected across midline via epiphyseal commissure (Fig. 6A). Lachrymal, a small paddle-like bone, without canal ossification, articulating with anterolateralmost point of lateral ethmoid. Nasal elongate, approximately half length of frontal, with canal ossification restricted to posteriormost part of bone adjacent to olfactory capsule. Nasal bones extending far anterior to ethmoid region of neurocranium over dorsal surface of upper jaw; terminating anterior to anteriormost point of upper jaw (Fig. 4A). Parasphenoid widest posteriorly ventral to occipital region of neurocranium; tapering anteriorly and abruptly to a narrow strut of bone along ventral midline of neurocranium (Fig. 6).

Dorsal-fin rays 4 or 5(*). Anal-fin rays 4, 5 or 6(*). All dorsal- and anal-fin rays unbranched and segmented; each in serial association with a narrow, rod-like pterygiophore, comprising proximal-middle radial only. Principal caudal-fin rays 4+4, dorsal procurrent rays 1 or 2, ventral procurrent rays 1 or 2. Principal caudal-fin rays and posteriormost dorsal and ventral procurrent rays unbranched and segmented; anteriormost dorsal and ventral procurrent ray unsegmented. Pectoral-fin rays 15 or 17; uppermost ray typically a tiny splint-like element comprised of a single hemitrichium; present on right side only in one C&S specimen (WAM P.34510-001). Lowermost 4-5 pectoral-fin rays more heavily ossified and approximately half length of upper rays, with foreshortened segments in each hemitrichium (sensu Lundberg & Marsh 1976) (Fig. 8). Remaining pectoral-fin rays (uppermost 10-12 rays) poorly ossified, without segmentation of hemitrichia (Fig. 8). Pelvic-fin rays I.4. Distal tip of spinous pelvic-fin ray narrow; strongly bifurcated proximally, embracing a small circular cartilaginous pelvic-radial cartilage. Pelvic-fin rays 1-3 increasing in length and width posteriorly. Caudal fin marginally truncate, tips of principal caudal-fin rays extended slightly beyond fin margin. Caudal-fin skeleton comprised of narrow upper and lower hypural plates (Fig. 10B); lower hypural plate with short antero- and posteroventral processes along ventral surface; tip of posteroventral process capped with cartilage. Epural a narrow, roughly triangular element, wider posteriorly than anteriorly, with broad cartilaginous posterodorsal margin; parhypural cartilage a small irregular element located at tip of posteroventral process of lower hypural plate (Fig. 10B). Dorsal-fin origin opposite anal-fin origin (Figs 2A, 4A). First dorsal-fin pterygiophore inserted between neural spines of vertebrae 20/21 or 21/22. First anal-fin pterygiophore inserted between hemal spines of vertebrae 19/20 or 20/21. Proximal-middle radials of dorsal- and anal-fin pterygiophores rod-like, without cup-like anterior process (Fig. 10A). Total number of vertebrae 38 or 39, consisting of 17 abdominal vertebrae and 21 or 22 caudal vertebrae (Fig. 4A). Ribs 11 or 12 associated with vertebrae 3-13/14. Epicentrals 14 or 15, associated with vertebrae 3-16/17.

Adhesive disc small (15-18% of SL), double (Fig. 9A); outer margin of disc smooth. Outline of anterior margin of disc slightly irregular, concave at midline. Posterior margin of smaller inner disc bordered by narrow flap of dense skin which has rolled inward in majority of specimens, concealing outer papillae of disc region B. Disc region A without papillae at centre; inner margin with single row of elongate papillae, transitioning to smaller papillae with circular or cuboid margins posterolaterally over ventral surface of pectoral-fin rays. Apapillate region of disc region A equal in width or slightly narrower than width of smaller inner disc. Disc region B with 2 transverse rows of papillae, comprised largely of elongate papillae with few smaller papillae with circular or cuboid margins scattered between elongate papillae. Disc region C covered in a thick pad of skin; apapillate. Disc region D with an irregular U-shaped papilla (Fig. 9A) or 2-3 circular to cuboid papillae at centre (Fig. 1A). Smaller inner disc connected to larger outer disc anteriorly via a narrow frenum of thick skin along ventral midline. Skin of frenum confluent with posterior margin of disc region D; lateral margins of frenum smooth to weakly crenate (Fig. 9A). Dorsal postcleithrum a poorly ossified sheet of bone with ~20 long, poorly ossified fimbrae along posterior margin (Fig. 9C). Medial edge of dorsal postcleithrum with a short peg-like strut of bone, directed towards ventral midline. Ventral postcleithrum well ossified, irregular in shape; approximately half size of dorsal postcleithrum (Fig. 9C). Posterior margin of ventral postcleithrum smooth, without fimbrae. Anteromedial edge of ventral postcleithrum with a concave facet that articulates with a dense pad of connective tissue located at posterior tip of basipterygium (Fig. 9C). Skin associated with last pelvic-fin ray attaching to base of pectoral fin opposite 4 th– 5th lowermost pectoral-fin rays. Skin over base of ventral pectoral-fin rays and lower half of shoulder girdle swollen and creating an obvious skin pad; epidermis of pad with a dense aggregation of club cells, giving skin pad a whitish appearance in preserved specimens (Fig. 8A). Pectoral radials with well-developed bony struts along ventral (pectoral radial 1), dorsal (pectoral radial 4), or both ventral and dorsal margins (pectoral radials 2 and 3) that interdigitate with struts borne on element(s) directly above and/or below (Fig. 8B, C).

Colouration.

In alcohol, head and body background colour uniformly pale cream to yellow (Fig. 2A). In life, head and body background colour golden-yellow to olive-brown (Fig. 3 A–C). Dorsal midline with variable number (10-14) of irregularly shaped light to dark brown markings; markings largest dorsal to centre of body, becoming smaller anterior or posterior to this point. Body side with a series of light to dark brown elongate markings forming an incomplete or complete horizontal stripe. Horizontal light to dark brown stripe along side of body continuing on side of head, through lower half of eye, to snout. Dorsal margin of light to dark brown stripe on head bordered by a lighter stripe, ranging from light yellow to white. Lighter stripe more pronounced in males. Iris red to orange. Fins uniform in colour without markings; colour matching body background colour.

Sexual dimorphism.

External sexual dimorphism largely restricted to urogenital papilla. Urogenital papilla of male with a blunt tip, located within a deep groove posterior to the anus and flanked anterolaterally by a pair of swollen skin folds, termed here accessory folds. Each accessory fold is roughly triangular in shape and appears to be confluent anteromedially with the heavily plicate skin surrounding the anus (Fig. 11A, B). Urogenital papilla of female with a needle-like tip, located along the dorsal surface of a robust tube-like structure which also bears the anus (Fig. 11C, D). This entire structure is accommodated within a deep pocket anterior to the anal-fin origin. In several specimens, the posteriormost tip of this structure is located within the pocket, suggesting some degree of mobility.

Eggs.

A female of 14.2 mm SL from WAM P.34510-001 contained ca. 20 mature eggs (ca. 10 within each ovary) of ca. 0.3-0.6 mm diameter. The largest eggs in each ovary exhibited a dark orange cap that may represent an "attachment apparatus" at the animal pole as described from the eggs of three species of European gobiesocid by Breining and Britz (2000).

Distribution.

Known presently only from two close sites in Western Australia (Cottesloe Reef and Trigg Reef platforms, Perth) and two sites in South Australia (Vivionne Bay and Victor Harbor) (Fig. 12). At the type locality (Cottesloe Reef platform), B. hutchinsi was collected from dense mats of macroalgae attached to rocky substrate in water up to 1 meter depth.

Etymology.

Named for Barry Hutchins, who discovered the new species. A noun in the genitive.

Remarks.

Hutchins (2008: 725) illustrated a specimen of Barryichthys hutchinsi from Western Australia, likely from the type locality at Cottesloe Reef platform (Perth). Specimens from South Australia (AMS I.20171-012, AMS I.49000-001) exhibit vertebral counts within the range of B. hutchinsi and are referred to this species. These specimens have been excluded from the type series but data obtained from these specimens has contributed to the description above.