Berkeleyia heroae Blake, 2017, new species

Berkeleyia heroae new species

Figures 1–2 A–E

Material examined. Argentina, Staten Island, off Tierra del Fuego, Hero Sta. 71-2- 16, 27 Apr 1971, 54.773°S, 64.712°W, intertidal, low water, holotype ( USNM 60633); Sta. 71-2 - 39, 24 Oct 1971, 54.797°S, 65.27°W, intertidal to 1 m, 3 paratypes (USNM 60634).

Description. Holotype complete, 9.5 mm long and 0.6 mm wide for 48 setigerous segments; largest paratype 9.7 mm long and 0.6 mm wide for 48 setigers. Color in alcohol: brown with several dark, diffuse pigment spots on prostomium. Thoracic region with 9–10 setigers, somewhat flattened dorsally; abdominal segments cylindrical in cross section. First 10–11 abdominal setigers with parapodia gradually shifted dorsally becoming fully shifted in middle and posterior setigers.

Prostomium conical, more or less rounded on anterior end (Fig. 1 A); without eyespots. Peristomium about twice as long as subsequent setigers, with paired ciliated nuchal organs on anterolateral margin (Figs. 1 A, 2A).

Thoracic and abdominal notopodia similar throughout body, with short, papillate postsetal lobes (Fig. 1 A–B). Thoracic neuropodia similar to notopodia; abdominal neuropodia with short, conical lobe and low presetal lamella (Fig. 2 B).

Thoracic parapodia with long crenulated capillaries. Abdominal notopodia with crenulated capillaries and 1–2 delicate furcate setae (Figs. 1 C, 2E); furcate setae with 5–6 more or less basally fused, thin needles between tynes and rows of fine barbs on shaft (Fig. 1 D); with SEM, rows of barbs on shaft observed to merge with bases of needles and with both structures continuous (Fig. 2 E); tynes with tips bearing openings only visible with SEM (Fig. 2 E). Abdominal neuropodia with 2–3 capillaries and 2–3 projecting spines; each spine with bidentate forked tips and transverse rows of barbs shaft (Figs. 1 C; 2C–D).

Branchiae from abdominal setiger 19–24, continuing to posterior end (Fig. 1 B); anterior branchiae short, then becoming long, straplike. Pygidium with anus directed posteriorly located between two lobes, each bearing terminal anal cirrus (Fig. 1 B). Large elongate ova, approximately 75 µm in diameter, present in anterior abdominal segments of one paratype.

Etymology. The species is named for the R/V Hero, former research vessel of the National Science Foundation.

Remarks. Berkeleyia heroae n. sp. has abdominal neuropodial acicular spines with bifid tips, the parapodia are reduced, with only short, conical postsetal lobes, the prostomium is conical, yet rounded on the anterior margin and the thoracic region is slightly flattened instead of inflated. This species differs from the type species B. profunda as well as B. abyssala n. sp., B. weddellia n. sp., and B. hadala n. sp. (below) in having bidentate neuropodial acicular spines instead of unidentate.

Distribution. Argentina, Staten Island, intertidal to 1 m.