Ypsilon Bullseye

biology_ecology

Biology. Little is known about this species. The largest known maximum size is 120.6 mm SL, and capture depths range from 1 m to 24 m. Haneda et al. (1966: 537) studied specimens obtained in a shrimp trawl, and described the anterior light organ as V-shaped, apparently overlooking the anterior portion of this structure (Fig. 4 b). Body depth (measured as dorsal-fin origin to pelvicfin origin) varies geographically. Specimens from western localities (Shark Bay to Broome) have deeper bodies than those from eastern localities (Gulf of Carpentaria to Port Denison) (0.40 - 0.45, mean 0.43 vs. 0.36 - 0.42, mean 0.40; means significantly different, T = 6.79, DF = 60, p <O. OOl). Eastern specimens tend to have higher lateralline scale counts and more segmented anal-fin rays than western specimens (Tables 2, 3); the higher anal-fin ray counts are particularly noticeable among Gulf of Carpentaria examples (Table 3).

Descriptions of two new species of the genus Pempheris (Pisces: Pempherididae) from Australia, with a provisional key to Australian species

description

Description. Dorsal-fin rays VI, lO (VI, lO; V-VI, 9 - 11, V only once, rarely 11); anal-fin rays III, 33 (III, 34; Ill, 30 - 36, once 30); pectoral-fin rays 17 (17; 16 - 18); pelvic-fin rays 1,5; principal caudal-fin rays 9 + 8; upper procurrent rays 6,2 (6,2; 5 - 8,1 - 2); lower procurrent rays 3,2 (3,2; 3 - 5,1 - 2); lateral-line scales 64 (68; 62 - 74, rarely more than 70); scale rows above lateral line 9 (10; 9 - 11); scale rows below lateral line 18 (18; 17 - 21); cheek scale rows 7 (6 - 9, extremes less common); predorsal scales 39 (39; 35 - 45, usually 37 - 43); circumpeduncular scales 22 (24; 22 - 26, usually 23 - 24); gill rakers 6 + 21 (7 + 20; 6 - 8, rarely 8 + 19 - 22); total gill rakers 27 (27; 25 - 30, most frequently 26 - 27, once 30). As percentage of SL: head length 35.2 (34.5; 31.8 - 39.4); head depth 33.7 (34.0; 30.0 - 39.7); snout length 7.7 (7.0; 5.8 - 8. l); eye diameter 14.8 (15.1; 13.2 - 16.5); interorbital width 8.9 (8.0; 6.5 - 9.3); upper jaw length 19.0 (19.0; 17.3 - 20.5); predorsal length 41.0 (40.0; 36.1 - 44.7); prepelvic length 38.1 (38.7; 33.8 - 49.3); preanal length 57.8 (59.9; 54.0 - 66.1); pelvic-fin origin to anal-fin origin 22.5 (24.5; 19.8 -

Descriptions of two new species of the genus Pempheris (Pisces: Pempherididae) from Australia, with a provisional key to Australian species

diagnosis

Diagnosis. Pempheris ypsilychnus is distinguished from all other members of the Pempherididae by the following combination of characters: all scales ctenoid and adherent; pelvic axillary scale present; lateral-line scales 62 - 74 (usually 63 - 69); gill raker counts on first arch 6 - 8 + 19 - 22 = 25 - 30 (usually 26 - 27); dark, Yshaped light organ visible through body wall between pelvic- and anal-fin origins, with its bifurcation around anus (Fig. 8).

Descriptions of two new species of the genus Pempheris (Pisces: Pempherididae) from Australia, with a provisional key to Australian species

discussion

Discussion. The relationships of these two new species cannot be determined at present. Preliminary results from a systematic revision of the family Pempherididae by the senior author, as well as the character distributions described by Tominaga (1968) and Jubb (1977), provide reason to doubt the monophyly of the two included genera, Parapriacanthus and Pempheris. The two new species exhibit the external features that traditionally have been used to characterise Pempheris (deep body, anal fin in scaly sheath, lateral-line scales extending to posterior margin of caudal fin), but share a number of internal features with the members of Parapriacanthus (cleithrum morphology, Y-shaped anterior light organ in Pempheris ypsilychnus). Their placement in Pempheris should, therefore, be regarded as provisional. Below is a key to the Australian species ofPempheris. In Australian waters, Pempheris can be distinguished from Parapriacanthus by: anal fin in scaled sheath (vs. no scaly sheath), 27 or more segmented anal-fin rays (vs. 27 or fewer), lateral-line extending to distal tips of medial caudal-fin rays (vs. to middle of medial caudal-fin rays), deeper body (head length about equal to body

Descriptions of two new species of the genus Pempheris (Pisces: Pempherididae) from Australia, with a provisional key to Australian species