Nettorhamphos radula, Kevin W. Conway & Glenn I. Moore & Adam P. Summers, 2017

Kevin W. Conway, Glenn I. Moore & Adam P. Summers, 2017, A New Genus and Species of Clingfish (Teleostei: Gobiesocidae) from Western Australia, Copeia 105 (1), pp. 128-140 : 130-131

publication ID	https://doi.org/ 10.1643/CI-16-560
DOI	https://doi.org/10.5281/zenodo.5662798
persistent identifier	https://treatment.plazi.org/id/AC2B87D7-1D61-CE72-FFC7-0F673159EA8E
treatment provided by	Plazi
scientific name	Nettorhamphos radula
status	sp. nov.

Treatment

Nettorhamphos radula View in CoL , new species

urn:lsid:zoobank.org:act:4A7AFFEE-D9E7-4F74-A586-129B5D401F60

Common name: Duckbilled Clingfish

Figures 1–10 View Fig. 1 View Fig. 2 View Fig. 3 View Fig. 4 View Fig. 5 View Fig. 6 View Fig. 7 View Fig. 8 View Fig. 9 View Fig. 10

Holotype.— WAM P.26052-004 , 40.2 mm SL, Australia, Western Australia, Indian Ocean, west of Five Fathom Bank, 33 meters in depth, 32°11'S, 115°34'E, B. R. Wilson and R. Buick (FRV Flinders), 30 June 1977. GoogleMaps

Paratype.— WAM P.25805-004, 1, 20.3 mm SL, Australia, Western Australia, Indian Ocean, west of Five Fathom Bank, 37 meters in depth, 32°17'S, 115°31'E, N. Sarti and R. George (FRV Flinders), 29 June 1977.

Diagnosis.— See generic diagnosis.

Description.— General body shape as in Figures 1 View Fig. 1 and 2 View Fig. 2 . Morphometric characters listed in Table 1 View Table 1 . Head wide, flat, strongly dorsoventrally compressed. Body moderately dorsoventrally compressed anteriorly, becoming increasingly laterally compressed posteriorly. Widest point of head wider than widest point of body (immediately behind head). Body width and depth tapering gradually posteriorly. Eye large, positioned on dorso-lateral surface of head; orbit visible in ventral view. Center of eye closer to tip of snout than to posterior margin of operculum. Snout long, broad, anterior margin rounded. Anterior nostril tubular, with long, fleshy cirrus extending from posterior margin. Posterior nostril surrounded by a low fleshy rim; situated posterior to imaginary vertical line through anterior margin of orbit. Gill membranes united and free from isthmus (gill membranes damaged in paratype). Subopercular spine well developed. Deep pocket present in branchiostegal membrane between posteriormost branchiostegal ray and medial face of subopercular spine.

Mouth terminal, large, posterior edge of upper jaw reaching imaginary vertical line through center of orbit when mouth closed. Upper jaw longer and wider than lower jaw, creating a large gap between margin of upper and lower jaws when closed ( Fig. 3 View Fig. 3 ). Upper lip fleshy, widest anteriorly, separated from snout by shallow groove. Lower lip with pair of shallow fleshy lobes below symphysis. Premaxilla with ~ 15 rows of ~ 40–50 tiny, dagger-like conical teeth ( Fig. 5D View Fig. 5 ). Lower jaw of holotype with ~ 10 rows of ~ 30–40 tiny, daggerlike conical teeth; lower jaw of paratype with single row of 8 large conical teeth anteriorly, followed by ~ 10 rows of 30–40 tiny, dagger-like conical teeth ( Fig. 5E View Fig. 5 ). Tiny, dagger-like teeth of lower jaw supported by thin, poorly ossified bony shelf on dorsal surface of dentary. Pharyngeal jaws comprising patch of 12–15 small conical teeth on pharyngobranchial toothplate 3 and two rows of 5–10 small conical teeth along ceratobranchial 5 ( Fig. 6C–E View Fig. 6 ). Poorly ossified basihyal with vertebrae 3–14. Epicentrals 12* or 13, associated with vertebrae 3–14* or 3–15.

Adhesive disc large, double ( Fig. 8 View Fig. 8 ); disc papillae and outer margin of disc degraded in both specimens. Disc papillae remaining in holotype as follows: disc region A with 1–2 incomplete transverse rows of papillae along anteromedian edge and smaller, sporadic clusters of papillae laterally over ventral surface of pelvic-fin rays, including a large patch comprised of 3 incomplete transverse rows beneath first soft pelvic-fin ray on left side; disc region B with 1–2 incomplete transverse rows of papillae along posterior edge and sporadic clusters of papillae anterolaterally; disc region C and D with incomplete median clusters of papillae. Basipterygium widest anteriorly, tapering posteriorly into thin, elongate processus ischiaticus ( Fig. 9A, B View Fig. 9 ); a large foramen at center of basipterygium. Anterior margin of pelvic girdle concave, tightly sutured to anteromedial face of pectoral girdle ( Fig. 9A, B View Fig. 9 ). Dorsal postcleithrum small, roughly semi-circular in shape; without contact to coracoid or ventral postcleithrum. Ventral postcleithrum larger than dorsal postcleithrum; irregular in shape, wider laterally then medially with a concave anterior margin and raised medial edge developed into a prominent anterodorsal process. Anterodorsal processes of ventral postcleithra in contact across midline and extended anterodorsally towards processus ischiatici of basipterygia ( Fig. 9D View Fig. 9 ). Elongate fimbriae not observed along posterior margin of ventral postcleithra. Four poorly ossified pectoral radials; tightly sutured via small, fingerlike projections of bone ( Fig. 9C View Fig. 9 ). Skin associated with last pelvic-fin ray attaching to base of pectoral fin opposite 6th lowermost pectoral-fin ray. No fleshy pad on lateral surface of pectoral base.

spatula-shaped. Other aspects of gill arches not observed. Branchiostegal rays 6; 2 anteriormost rays articulating medially with hyoid bar along anterior ceratohyal; posterior rays articulating with hyoid bar laterally, including 3 along anterior ceratohyal and 1 along posterior ceratohyal ( Fig. 6A, B View Fig. 6 ).

Cephalic lateral-line system with 2 pores in nasal canal; 2 pores in postorbital canal; 2 pores in lacrimal canal; 3 pores in preopercular canal; and 2 pores in mandibular canal. Autosphenotic with large spine-like process laterally ( Fig. 4 View Fig. 4 ). Lacrimal a tiny tube-like ossification ( Fig. 5A, C View Fig. 5 ).

Dorsal-fin rays 5 or 6*. Anal-fin rays 7 or 8*. Principal caudal-fin rays 5þ4, dorsal procurrent rays 3*, ventral procurrent rays 2*. Pectoral-fin rays 21* or 22. Pelvic-fin rays I.4. All fin rays unbranched and segmented. Pterygiophores not observed. Caudal fin truncate. Caudal-fin skeleton comprised of upper and lower hypural plates ( Fig. 7D View Fig. 7 ). Epural and parhypural not observed. Dorsal-fin origin situated slightly posterior to imaginary vertical line through anal-fin origin. Dorsal and anal fins collapsed and tightly adhered to body in both specimens; aspects of fin membranes not observed. Total number of vertebrae 33* or 34, consisting of 15þ18* or 16þ18 ( Fig. 7 View Fig. 7 ). Ribs 11, associated Coloration.— In alcohol, head and body background color pale cream (holotype; Fig. 1 View Fig. 1 ) or light brown (paratype; Fig. 2 View Fig. 2 ). Dorsal surface of head with small, evenly spaced yellow spots tentatively identified as remnants of xanthophores in holotype only ( Fig. 10 View Fig. 10 ). Fins hyaline. Coloration in life unknown.

Distribution and habitat.— Known to date only from two locations to the west of Five Fathom Bank (Indian Ocean), off the coast of Fremantle, Western Australia ( Fig. 11 View Fig. 11 ). The new species was collected via trawls through algae/sponge reefs between 33–37 meters in depth. Other species of fishes collected by the same trawls include the pipefish Stigmatopora nigra, the labrids Austrolabrus maculatus, Eupetrichthys angustipes, Siphonognathus caninus, and S. attenuatus, and the gobiesocids Alabes occidentalis and ‘‘Genus A sp. 2’’ (sensu Hutchins, 2008).

Etymology.— From the Latin radula , a tool used for scraping. In reference to the many tiny conical teeth on the lingual surface of the premaxilla and dentary, which are reminiscent of the radula of a snail. A noun in apposition.