Jaffaia jaffaensi s (Blochmann, 1910)

(Fig. 4E–K)

1910 Magasella jaffaensis Blochmann, p. 92, pl. 27, figs. 6–9.

1911 Campages jaffaensis (Blochamnn) — Hedley, 1911, p. 114, pl. 20, figs. 41–42.

1927 Jaffaia jaffaensis (Blochmann) —Thomson, pp. 254–255, fig. 84.

1975 Jaffaia jaffaensis (Blochmann) —Richardson, pp. 201–202, pl. 15, figs. 9–13.

2010 Jaffaia jaffaensis (Blochmann) —Zezina, p. 1195.

2023a Jaffaia jaffaensis (Blochmann) —Verhoeff, pp. 17–22, figs. 7–8.

Material examined. NW Australia, Lacepede Archipelago, stn SO1/84/054, 15°51.2’S, 120°44.3’E to 15°49.3’S, 120°45.3’E, 348–350 m, 10 February 1984, coll. S.M. Slack-Smith —two complete specimens (WAM Z59451) ; Kimberly, Beagle Bay, stn SO1/84/058, 15°12.8’S, 121°05.9’E to 15°10.4’S, 121°09.2’E, 404–410 m, 11 February, coll. S.M. Slack-Smith —one complete specimen (WAM Z59455) ; Kimberley, Beagle Bay, stn SO1/84/059, 15°09.4’S, 121°05.5’E to 15°11.4’S, 121°03.8’E, 448–450 m, 11 February 1984, coll. S.M. Slack-Smith —20 complete specimens (WAM Z59457) ; Kimberly, Beagle Bay, stn SO1/84/060, 15°08.6’S, 121°03.4’E to 15°06.0’S, 121°06.6’E, 500–504 m, 11 February 1984, coll. S.M. Slack-Smith —86 complete specimens (WAM Z59458, WAM Z59459, WAM Z59460) ; Kimberley, Cape Leveque, stn SO1/84/061, 14°39.5’S, 121°28.5’E to 14°41.9’S, 121°25.0’E, 500–506 m, 12 February 1984, coll. S.M. Slack-Smith —one complete specimen (WAM Z59461) ; Kimberley, Cape Leveque, stn SO1/84/063, 14°43.1’S, 121°33.1’E to 14°44.9’S, 121°31.6’E, 408–410 m, 12 February 1984, coll. S.M. Slack-Smith —six complete specimens (WAM Z59462) ; Kimberley, Cape Leveque, stn SO1/84/065, 14°49’S, 121°36.1’E to 14°50.8’S, 121°35.6’E, 300–302 m, 12 February 1984, coll. S.M. Slack-Smith —two complete specimens (WAM Z59464) ; Kimberley, Broome, Roebuck Bay, stn SO1/84/121, 18°04’S, 118°14’E to 18°00’S, 118°19’E, 396–400 m, 24 February 1984, coll. S.M. Slack-Smith —one complete specimen (WAM Z59473) ; Rowley Shoals, Imperieuse Reef, stn COUR2/83/26, 18°05’S, 118°08’E, 440–442 m, 22 August 1983, coll. N. Sinclair and P.F. Berry —one complete specimen (WAM Z59474) ; Kimberley, Cape Preston, stn COUR2/83/33, 18°34’S, 117°17’E, 475–477 m, 23 August 1983, coll. N. Sinclair and P.F. Berry —four complete specimens (WAM Z59477) ; stn SO1/84/58, 15°12.8’S, 121°05.9’E to 15°10.4’S, 121°09.2’E, 410 m, 11 February 1984, coll. S.M. Slack-Smith —four complete specimens (WAM Z99090) .

Depth range. 300–506 m.

Measurements. Length 20.1 mm, width 19.3 mm, thickness 10.3.

Remarks. With 128 specimens Jaffaia jaffaensis is a dominant species in the material under study. The shell is subcircular in outline, biconvex with valves nearly equally convex, and gently unisulcate. Its surface is smooth with numerous growth lines. The beak is suberect, beak ridges present. The foramen is small, of mesothyrid to permesothyrid type, deltidial plates conjunct. The long loop is attached to the median septum.

Jaffaia jaffaensis is an Australian endemic species, well known from southern Australian coast from Perth to Sydney (Richardsan 1994, fig. 4; Logan 2007; Verhoeff 2023a). From NW Australia J. jaffaensis is recorded for the first time.