Chopa de Gladius

description

Description. Body elongate and relatively compressed (body depth: 33.3 – 41.6, mean 39.6 % SL), (body width: 12.6 – 19.3, mean 16.8 % SL). Caudal peduncle longer (18.7 – 26.5, mean 23.2 % SL) than deep (9.9 - 11.8, mean 11.0 % SL). Head 22.1 – 30.5 % SL (mean 25.3 % SL), frontal slope of head not steep, but smoothly pointed (Figure 2 and 3 A). Interorbital width 10.7 – 12.3 % SL (mean 11.5 % SL) and with 12 – 16 scale rows. Eye diameter (4.3 – 9.4, mean 6.1 % SL) nearly equals snout length (4.5 – 8.6, mean 6.8 % SL). Eye with yellow iris and silvery line underneath, olive-green horizontal streak stretching from mouth to behind posterior edge of eye. Operculum with green vertical bar running down rear of preoperculum (Figure 3 and 4). Mouth terminal, relatively short premaxilla (5.8 – 8.4, mean 7.2 % SL). Posterior end of maxilla reaches behind anterior edge of eye to right below centre of pupil. Preorbital region without scales. Teeth in single outer row, all incisor-shaped on both premaxilla and dentary (8 – 37 and 8 – 36, respectively). First gill arch with 3 – 5 (mean 4.2) gill rakers, externally, on upper part of arch and 11 – 15 (mean 12.5) on lower part of first arch, giving

Kyphosus gladius, a new species of sea chub from Western Australia (Teleostei: Kyphosidae), with comments on Segutilum klunzingeri Whitley

diagnosis

Diagnosis. Distinguished from other species of Kyphosus from the Indian Ocean and the Pacific Ocean by the following combination of characters: body elongate and compressed. Mouth terminal. Silvery line under eye, colour silvery to bluish metallic; operculum with a vertical green bar running down rear of preoperculum; dorsal part of body without dark counter-shading. Caudal peduncle depth, 9.9 - 11.8 % SL; sixth dorsal fin spine length, 8.7 – 11.9 % SL; body depth, 33.3 – 41.6 % SL; 15 – 19 total gill rakers externally, 3 – 5 gill rakers on upper limb externally, 11 – 15 gill rakers on lower limb externally; 44 – 55 pored scales in lateral line, 55 – 63 scale rows in lateral line with or without pores, 49 – 57 scale rows in longitudinal row; 11 – 12 soft dorsal fin rays, 11 – 12 anal fin rays, 10 + 16 precaudal- and caudal vertebrae.

Kyphosus gladius, a new species of sea chub from Western Australia (Teleostei: Kyphosidae), with comments on Segutilum klunzingeri Whitley

distribution

Distribution. Kyphosus gladius sp. nov. appears restricted to Western Australia, and to date has been collected from the Houtman Abrolhos Islands southwards to Cape Naturaliste and down to Albany on the southern coast of Western Australia (28 º 29 ’ – 35 º 00 ’ S). Most western record is from Rockingham near Perth, and most easterly record from Albany (113 º 41 ’ – 117 º 52 ’ E) (Figure 1). All reports involve depths from 0 to 15 m. It co-occurs with Kyphosus bigibbus, K. cornelii and K. sydneyanus. Examination of museum collections (WAM and AMS) and available underwater photographs suggest that K. gladius sp. nov. is yet to be recorded from South Australia, Victoria, Tasmania and the eastern coast of Australia. However, it is likely that the distribution might extend further eastward from Albany along the coast of the Great Australian Bight. The northernmost records are from a tissue sample and underwater photographs from the Wallabi Group in the Houtman Abrolhos Islands; whether the distribution extends further north is uncertain, although no specimens were observed during fieldwork on Ningaloo Reef. The most southern record is from Albany. The Houtman Abrolhos Islands represent

Kyphosus gladius, a new species of sea chub from Western Australia (Teleostei: Kyphosidae), with comments on Segutilum klunzingeri Whitley

etymology

Etymology. The specific name gladius was chosen as the shape of the body resembles the roman gladius sword, which is widest towards the point and tapers towards the hilt. The relatively elongate body and shallow caudal peduncle, along with the metallic-bluish colouration, resembles this roman sword. The genus name Kyphosus is masculine, hence gladius. Comparison. Kyphosus gladius differs from the sympatric K. cornelii in having a lower number of soft dorsal fin rays (11 – 12 versus 14 – 16, respectively), and lacking a white edge to the caudal fin as in K. cornelii. Furthermore, K. gladius has interorbital scale rows (12 – 16), whereas interorbital scales are absent in K. cornelii.

Kyphosus gladius, a new species of sea chub from Western Australia (Teleostei: Kyphosidae), with comments on Segutilum klunzingeri Whitley