Levinsenia multibranchiata (Hartman, 1957)

Figures 4 A–D, 7D

Paraonis multibranchiata Hartman, 1957: 332–333; 1969: 79–80, Fig. 1.

Tauberia multibranchiata . — Strelzov, 1973: 135–136, Figs 11(1), 59.

Levinsenia multibranchiata . — Blake, 1996: 36, Fig. 2.3.

Material examined. USA, California, Santa Barbara County, Santa Barbara Channel Basin, 18.0 miles bearing 135° True from Point Conception Light, 34°14’10’’N, 120°12’45’’W, 502.9 m depth, green mud, Hayward orange peel grab, R / V Velero IV, Sta. 3731-55, coll. Allan Hancock Foundation, 12 December 1955, 14 paratypes (one specimen mounted on SEM stub) (LACM-AHF POLY 648) .— Orange County, Huntington Beach, OCSD NPDES Survey 9270, Sta. C2, rep. 5, 33°36.12’N, 117°56.02’W, 56 m depth, 0.1 m ² Van Veen grab, 1.0 mm sieve, 1 specimen (LACM-AHF 12578); survey 9382, Sta. C 2, rep. 1, 33°36.12’N, 117°56.02’W, 56 m depth, 0.1 m ² Van Veen grab, 1.0 mm sieve, 12 specimens (LACM-AHF 12579); survey 9279, Sta. C 2, rep. 3, 33°36.12’N, 117°56.02’W, 56 m depth, 0.1 m ² Van Veen grab, 1.0 mm sieve, 20 specimens (LACM-AHF 12580); survey 9279, Sta. C 2, rep. 5, 33°36.12’N, 117°56.02’W, 56 m depth, 0.1 m ² Van Veen grab, 1.0 mm sieve, 2 specimens (LACM-AHF 12581); survey 95109, Sta. C 2, rep. 1, 33°36.12’N, 117°56.02’W, 56 m depth, 0.1 m ² Van Veen grab, 1.0 mm sieve, 1 specimen (LACM-AHF 12582) .— San Diego County, Carlsbad, Encina Treatment Plant NPDES Survey 9344, Sta. R2, rep. 1, ~ 33°07.57’N, 117°20.69’W, 46 m depth, 0.1 m ² Van Veen grab, 1.0 mm sieve, 1 specimen (LACM-AHF 12583); survey 9344, Sta. R2 , rep. 3, ~ 33°07.57’N, 117°20.69’W, 46 m depth, 0.1 m ² Van Veen grab, 1.0 mm sieve, 1 specimen (LACM-AHF 12584) .

Description. Specimens up to 30 mm long, 0.15–0.25 mm wide. Thorax slightly inflated in prebranchial chaetigers, rounded in cross section thereafter. Body tan. Prostomium conical, wider than long; poorly-developed terminal sensory organ; pair of ciliated peristomial nuchal organs; median antenna absent (Fig. 4A). Branchiae begin on chaetigers 7–8, 20–36 pairs; thin, tapering, five times longer than wide (Fig. 4B); cilia present on lateral edges, with connecting transverse dorsal bands of short cilia. Notopodial post-chaetal lobes papilla-like on chaetiger 1, digitate in branchiate region, shorter post-branchial. Notopodial sensory pores (Fig. 4C) present on all segments. Neuropodial post-chaetal lobes absent. Noto- and neuropodial capillary chaetae from chaetiger 1. Acicular neurochaetae, 5–7 per fascicle, begin post-branchial; each spine slightly curved, tapering and thinner distally, with fringe of fibrils on convex margin; spines alternating with capillary chaetae (Fig. 4D). Pygidium with dorsal anal pore, mid-ventral lobe, two short anal cirri.

Methyl green stain. None present (Fig. 7D).

Type locality. Southern California, Santa Barbara Basin .

Distribution. Southern and Central California, 45–540 m deep.

Remarks. Levinsenia multibranchiata is readily distinguished from other SCB species by the more numerous and elongate branchiae. For information on diagnostic character differences, see the dichotomous key and Table 2.