Califia bilamellata Blake, 2017, new species

Califia bilamellata new species

Figures 38–39

Material examined. Southern Chile, Seno Reloneavi, the Bay off Puerto Monntt, N of the light buoy NE of Isla Tengo, LUCE Sta. 4A, 11 Sep 1948, 41°28′54″S, 72°57′24″W, 13–16 m, paratype (SMNH 4351); Golfo de Ancud, SW of Isla Tabon, LUCE Sta. M-44A, 24 Jan 1949,41°58′S, 73°18′W, ca. 200 m, holotype (SMNH 4350). —Off Uruguay, IBM Sta. N-1073, R/ V A. Knipovich, 115–117 m, muddy sand, 4 specimens (2, USNM 1407120), (2, SEM, JAB).

Description. All specimens incomplete; holotype 12 mm long and 1.2 mm wide for 45 setigers; paratype 6.6 mm long and 0.5 mm long for 39 setigers; largest Uruguayan specimen 15 mm long, 1 mm wide for 70 setigers. Thoracic region divided into modified anterior region consisting of three setigers with prominent neuropodial spines and few capillaries (Fig. 38 A, 39A, C) followed by more typical region with numerous neuropodial capillaries and few spines extending to setiger 16–18. Color in alcohol: light tan.

First three modified thoracic setigers appearing different from following setigers due to presence of enlarged neurosetae (Figs. 38 A, 39A–C). Prostomium triangular, narrowing to pointed tip on anterior margin (Figs. 38 A, 39C), or blunted based on preservation (Fig. 39 A); eyespots absent; nuchal organs paired transverse slits at border of prostomium and peristomium (Fig. 39 A) proboscis a soft sac, partially everted on paratype. Peristomium not annulated, completely fused with prostomium (Figs. 38 A, 39A).

Thoracic notopodial lamellae fingerlike from setiger 1 (Fig. 38 A), short at first becoming longer and more prominent from setiger 4–5; neuropodia of Chilean specimens with single postsetal lamella from setiger 4, continuing to setiger 9, then second neuropodial lamella from setiger 10–12 (Fig. 38 A), continuing to setiger 16– 18, then second one lost; Uruguayan specimens with second neuropodial lamella only on last 2–3 thoracic setigers; a single subpodial lamella present through first 3–6 anterior abdominal segments (Fig. 38 F). Abdominal parapodia all similar, with long, thin notopodial lobe and divided neuropodial lobe (Fig. 38 F); no interramal cirrus.

Thoracic notopodia with simple fascicle of crenulated capillaries; abdominal notopodia with anterior ventral fascicle of 3–4 thick crenulated capillaries and a dorsal fascicle of 10–12 thinner crenulated capillaries, and 1–2 furcate setae (Fig. 38 F). Furcate setae with unequal tynes connected by 3–4 thin needles on each side, merging and fused with tynes; tips of tynes with distinct openings (Fig. 39 G–H); shafts generally smooth except for few minute barbs, but no transverse ridges.

Thoracic neuropodia with three types of setae: (1) an anterior row of short, narrow, prominently crenulated blunt-tipped uncini having a notched tip and hyaline hood or sheath (Fig. 38 B, D–E); (2) heavy uncini on setigers 1–3 in second and third row with a smooth shaft and pointed to worn tip, sometimes with remnants of hyaline hood or with hood worn to frayed fibril endings or entirely absent (Fig. 38 B–C), with SEM sheath sometimes frayed on tip, extending posteriorly along shaft to where weak transverse ribs apparent (Fig. 39 B,E); (3) crenulated capillaries. Narrow uncini (1) present in all thoracic setigers, numbering 5–6 throughout, representing anterior row of uncini in setigers 1–3, then shifted ventrolateral in setigers 4–18 and surrounded by several rows of capillaries (Fig. 39 F); heavy uncini (2) limited to second and third rows in setigers 1–3 numbering 4–5 per row (Figs. 38 B, 39B, D); capillaries limited to small dorsally located fascicle in setigers 1–3, then in dense fascicles of 4–6 rows in setigers 4–18. Abdominal neuropodia with 2–3 narrow aciculae, barely emergent and 4–5 thin, weakly barbed to smooth capillaries (Fig. 38 F).

Branchiae from setiger 9–10 (Fig. 38 A), short, conical at first, becoming very broad at base, then triangular in middle of thoracic region; anterior abdominal branchiae short, triangular (Fig. 38 F), becoming long, narrow in posterior segments. Pygidium unknown.

Etymology. The specific name, bilamellata, is Latin (bi for two; lamella for plate) and refers to the double neuropodial lamellae of the posterior thoracic segments.

Remarks. Califia bilamellata n. sp. is the first species of the genus to be collected from continental shelf depths; all previously described species have been recorded from slope and abyssal depths. Califia bilamellata n. sp. differs from all other species of the genus in having one type of narrow uncini present in all of the thoracic setigers in addition to the typical heavy modified uncini of setigers 1–3. The narrow uncini occur in the anterior row in setigers 1–3 and in a more ventral location in following thoracic setigers. In other species, the narrower uncini may occur in setigers 4–5, but never over the entire thoracic region (see discussion for C. chilensis above). By having two distinct types of uncini, the smaller of which is present throughout the thoracic region with capillaries, this species shares generic characters with species of Scoloplos and may represent a transitional species between the two genera. In addition, C. bilamellata n. sp. is unique among species of Califia in having two thoracic neuropodial lamellae in posterior thoracic setigers and in having an additional subpodial lobe in some anterior abdominal setigers. The Chilean and Uruguayan specimens appear to represent the same species with the only apparent difference being that the paired postsetal lamellae of thoracic neuropodia are distributed over 10 or more setigers in the former and restricted to the last 2–3 setigers in the latter. However, only six specimens of this species have been collected to date and variation is not well documented.

Distribution. Chile, 13–200 m in fine to coarse sand; off Uruguay, 115–117m in muddy sand.