Acryptolaria pygmaea n. sp.

(Figs 27; 30; 32J; Table 28)

MATERIAL EXAMINED. — Norfolk Ridge. SMIB 4, stn DW 60, 23°00.1’- 22°59.4’S, 167°21.6’- 167°21.7’E, 500-535 m, 10.III.1989, 1 stem c. 11 mm high, holotype (MNHN-Hy.2009-0173).

Coppiniae without defensive tubes. Gonothecae flask-shaped, tightly set together and with coalesced walls (Fig. 26D, E). Diameter strongly decreasing distally, forming a short neck (Fig. 26E) with a circular aperture (Fig. 26D, E).

ETYMOLOGY. — The specific name pygmaea, latinization of the Greek adjective “pygmeios”, small, refers to the dwarf hydrothecae; it follows in gender the (feminine) genus name.

ECOLOGY AND DISTRIBUTION. — Acryptolaria pygmaea n. sp. was collected at depths between 500 and 535 m in the Norfolk Ridge area.

DESCRIPTION

Stem 11 mm high, in bad condition and with extremely fragile perisarc.The stem has only two primary branches, each with a secondary branch (Fig. 32J).

Hydrothecae alternately arranged in approximately one plane (Fig. 27A), tubular, practically cylindrincal (Fig. 27); diameter decreasing only in the extreme basal part. Hydrotheca smoothly curved outwards, adcauline wall convex,adnate over a variable extension, from about one-half to five-sixths of its lengh (adnate/ free ratio 1.3-5.3); abcauline wall concave, though straight or slightly convex in its basal part.Hydrothecal aperture circular and directed outwards, virtually parallel to long axis of branches; rim even.

Large nematocysts relatively very large and fusiform (Fig. 30).

Coppinia not observed.

REMARKS

Notwithstanding the scarcity of material, we consider that Acryptolaria pygmaea n. sp. is an easily identifiable species. It is well characterized by its relatively tiny hydrothecae and huge nematocysts. It is allied to A.minuta and A.minima in the size of the hydrothecae, being closer to the former by the relatively long and thin hydrothecae.However, it is easily distinguishable from these two species by the size of the nematocysts that are distinctly larger than those of A.minima (25.8 × 9.8 µm in the holotype) and much larger than those of A. minuta (16.7 × 6.3 µm in the holotype).