Ekpontocypris epicyrta (Maddocks 1969)

Propontocypris (Ekpontocypris) epicyrta

Propontocypris(?) sp. Holden, 1967, p. 18, figs, 11a–b. Species DK Maddocks, 1966, p. 51, fig. 30–2.

ETYMOLOGY.—Greek epikyrtos, humpbacked.

TYPE-SPECIMENS.—Holotype USNM 121165, para-types USNM 121166–121171,121249.

TYPE-LOCALITY.—“Anton Bruun” cruise 7 station 381B, near Walterson Shoal.

DIAGNOSIS.—Carapace smooth, extremely thin, lacking external setae; dorsal margin highly arched, greatest height located anterior to midlength; ventral margin very deeply indented and sinuous, anterior margin broadly and obliquely rounded, posteroventral margin narrowly rounded; margins compressed, greatest thickness of medial expansion located slightly above midheight Zone of concrescence very broad, radial pore canals narrow and abundant with many false radial pore canals; line of concrescence irregular; normal pore canals tiny and inconspicuous but abundant. Muscle-scar pattern a compact rosette of five wedge-shaped scars. Carapace yellow and transparent with brown margins, body and appendages yellow, eyes brown.

Palp of maxilla lacking dorsomedian seta on basal podomere, one of distal setae of basal podomere

exceptionally long; all setae of palp and masticatory processes long and simple; posterolateral seta of base thick and feathered. Palp of first thoracic leg of male with slender quadrangular basal podomere carrying long thin peg and especially long seta, slender curved hook ending in unusually long digitiform seta. Third thoracic leg with pectinate seta somewhat shorter than usual, finely barbed; lacking lateral cusps on penultimate podomere, lacking spines or setae at knee joint. Copulatory organ of male oblong, bluntly truncated, dorsal and ventral margins slightly concave; lateral flap visible, no copulatory tube seen; vas deferens moderately large.

MATERIAL.—Nosy Bé: one adult female (?), one juvenile male, another juvenile living, one subfossil valve. Walterson Shoal, station AB–381B: one adult male with dried remains of appendages. George Sound, New Zealand: one whole carapace and nine valves, all subfossil.

DIMENSIONS.—Adult male specimen USNM 121165 from Walterson Shoal: left valve, length 0.75 mm, greatest height 0.37 mm, located 0.29 mm from anterior, thickness 0.13 mm; right valve, length 0.76 mm, greatest height 0.38 mm, located 0.31 mm from anterior, thickness 0.17 mm.

Adult female specimen KU1000047 from Nosy Bé: length 0.57 mm, height 0.29 mm

Female (?) USNM 121166 from New Zealand: right valve, length 0.76 mm, greatest height 0.40 mm, located 0.34 mm from anterior, thickness 0.17 mm.

Male (?) USNM 121167 from New Zealand: left valve, length 0.70 mm, greatest height 0.36 mm, located 0.28 mm from anterior, thickness 0.14 mm.

Male (?) USNM 121168 from New Zealand: right valve, length 0.72 mm, greatest height 0.37 mm, located 0.32 mm from anterior, thickness 0.14 mm.

HABITAT.—Nosy Bé: collected living in washings of two corals and of alga-encrusted valves of the reef-dwelling bivalve Tridacna. Walterson Shoal: collected living in sediment at 38 m depth.

SUBFOSSIL DISTRIBUTION.—Nosy Bé: known only from a single sample of carbonate beach sand at Antsakoabe. New Zealand: station RM1004, George Sound.

Holden (1967) illustrates a form with identical outline dredged from drowned Neogene terraces in the Hawaiian Islands.