Abyssochrysoidea, Tomlin, 1927

Simone, Luiz Ricardo L., 2024, New species, misidentifications and problematic taxonomy of some Atlantic South American marine mollusks: a review, Papéis Avulsos de Zoologia 64, pp. 1-104 : 13

Superfamily Abyssochrysoidea Family Abyssochrysidae

Genus Abyssochrysos Tomlin, 1927

Abyssochrysos quasilissus new species ( Fig. 8 ) https://zoobank.org/ 8151116A-E473-48DB-92AB-0DB0F63F9038

Types: Holotype MZSP 117078 , shell . Paratype: BRAZIL. Espírito Santo; slope off ItaÚnas ( R. V. Marión-Dufresne col., MD55 ), 18°59′S 37°48′W, 1,540-1,550 m, MZSP 117074 , 1 shell (sta. DC70 , 26.v.1987), 19°40.6′S 37°48.1′W, 790-940 m, MNHN-IM-2000-39806, 2 shells (sta. CB77 , 27.v.1987) .

Type locality: BRAZIL. Espírito Santo ; off ItaÚnas, 18°59′S 37°48′W, 607-620 m [ R. V. Marión-Dufresne col., MD55 sta. DC73, 27.v.1987] .

Diagnosis: Shell from SE Brazilian coast,of ~ 6 mm,sculptured only by weak oblique striations.

Description: Shell ~ 6 mm; ~2.5 times longer than wide; spire angle ~24° ( Fig. 8 A-C, F-H). Color pure white. About 9 convex whorls, with wider region just above suture, causing suture implantation inferior to preceding whorl. Protoconch ( Fig. 8E, I ) of 1 whorl, width 0.9 mm, mamillated, blunt; limit with teleoconch unclear. Teleoconch surface glossy, shining; sculpture weak striations, like narrow undulations, ~ 25 in penultimate whorl, prosocline inclined at ~15° in relation to longitudinal shell axis ( Fig. 8B, G, H ); sculpture present since first teleoconch whorls. Aperture rounded ( Fig. 8A, F, D ), occupying ~24% of shell length, ~50% of shell width. Outer lip fragile, with cutting edge; inner lip with inferior ⅔ weakly concave, curved outside covering umbilicus, superior ⅓ as very thin callus attached to preceding whorl; inferior apertural region angulate, slightly turned to left. Umbilicus opened ( Fig. 8D ), with simple edges.

Etymology: The specific epithet is a conjunction of Latin prefix quasi, meaning like, almost; with the Greek word lissos meaning smooth, polished, an allusion to the almost smooth surface of the shell.

Distribution: Off Espírito Santo to Rio de Janeiro, Brazil.

Figures

Figure 8. Abyssochrysosquasilissus type shells:(A-E) holotype MZSP 117078 (L 5.6 mm);(A) frontalview;(B) rightview;(C) dorsal view,(D)inferior-slightly frontal view;(E) detail of apex,profile;(F-I)paratype MZSP 117074 (L 6.4 mm).