Fabricinuda longilabrum, Fitzhugh, 2002

Fitzhugh, K., 2002, New species of Fabricinuda Fitzhugh and Pseudofabriciola Fitzhugh (Polychaeta: Sabellidae: Fabriciinae), with an emendation of Pseudofabriciola australiensis (Hartmann-SchroÈder), Journal of Natural History 36 (8), pp. 893-925 : 894-899

Fabricinuda longilabrum n. sp.

(®gures 1, 2; tables 1, 3)

Material examined. Paci®c Ocean, China Sea, Gulf of Thailand. See Appendix for speci®c station data, depth 60±70 m, coll. Battelle Ocean Sciences, August 1990. HOLOTYPE: LACM-AHF 1975 , sta. EWP-I-C-1 . PARATYPES: LACM-AHF 1976 , sta. BWC-I-D-2 (two specimens) ; LACM-AHF 1977 sta. BWC-I-D-3 (one specimen) ; LACM-AHF 1978 , sta. BWC-III-D-1 (one specimen) ; LACM-AHF 1979 , sta. BWC- III-D-2 (®ve specimens) ; LACM-AHF 1980 , sta. BWC-III-D-3 (one specimen) ; LACM-AHF 1981 , sta. EPB-I-D-1 (12 specimens) ; LACM-AHF 1982 , sta. EPB- III-C-3 (one specimen) ; LACM-AHF 1983 , sta. EPB-III-D-1 (one specimen) ; LACM-AHF 1984 , sta. EPB-III-D-2 (seven specimens) ; LACM-AHF 1985 , sta. EPB-III-D-3 (three specimens) ; LACM-AHF 1986 , sta. EWK-I-D-1 (12 specimens) ; LACM-AHF 1987 , sta. EWK-I-D-2 (one specimen) ; LACM-AHF 1988 , sta. EWK- I-D-3 (two specimens) ; LACM-AHF 1989 , sta. EWK-III-D-1 (four specimens) ; LACM-AHF 1990 , sta. EWP-I-C-1 (four specimens) ; LACM-AHF 1991 , sta. EWP- I-D-1 (six specimens) ; LACM-AHF 1992 , sta. EWP-I-D-2 (®ve specimens) ; LACM- AHF 1993 , sta. EWP-III-D-1 (two specimens) ; LACM-AHF 1994 , sta. EWP-III- D-2 (two specimens) ; LACM-AHF 1995 , sta. EWP-III-D-3 (two specimens) ; LACM-AHF 1996 , sta. PCP-I-A-1 (one specimen) ; LACM-AHF 1997 , sta. PCP-I- D-2 (two specimens) ; LACM-AHF 1998 , sta. PCP-III-C-1 (two specimens) ;

LACM-AHF 1999 , sta. PCP-III-C-3 (one specimen) ; LACM-AHF 2000 , sta. PWE- I-D-2 (one specimen) ; LACM-AHF 2001 , sta. Control-3-3 (one specimen) ; LACM- AHF 2002 , sta. Control-5-1 (one specimen) ; LACM-AHF 2003 , sta. Control-5-3 (two specimens) ; LACM-AHF 2004 , sta. Control-6-1 (one specimen) .

Description. Holotype a complete (branchial crown detached) female with eight thoracic and three abdominal setigers. Branchial crown length 1.11 mm, remainder of body 3.25 mm long, maximum width 0.17 mm. Body very slender, slightly tapering posteriorly (®gure 1A). Branchial crown with three pairs of radioles, distal ends ®lamentous, same width as pinnules. Dorsalmost radioles with two pairs of pinnules, median and ventralmost radioles with three to four pairs; all pinnules terminate at about same height, slightly shorter than tips of radioles. Dorsal lips erect, three times longer than wide, distally rounded (®gure 1B). Ventral lips and ventral ®lamentous appendages absent. Dorsal margins of branchial lobes not fused to one another. Branchial hearts present. Anterior peristomial ring collar as a low ridge (®gure 1A), narrowly separated mid-dorsally; dorsolateral collar margins as small lobes partially overlapping mid-dorsal medial lobe (®gure 2A). Mid-dorsal medial

1. Ventral margins of branchial lobes: (0) as narrow shelf-like processes; (1) as ventral ®lamentous appendages (i.e. vascularized and unbranched).

2. Branchial lobes adjacent to dorsalmost radioles: (0) as dorsal lips; (1) as even shelf continuous with ventral branchial lobe margins.

3. Branchial crown: (0) located over entire anterior end; (1) shifted dorsally.

4. Anterior peristomial ring: (0) at least as wide as long; (1) distinctly longer than wide.

lobe distally rounded, extending slightly above collar. Annulation between collar and anterior peristomial ring not visible. Anterior peristomial ring distinctly longer than wide, about six times longer than posterior peristomial ring. Annulation between rings visible ventrally and laterally (®gure 2A, B). Mid-dorsum of anterior peristomial ring with wide, shallow groove extending from mid-dorsal collar separation to posterior peristomial ring (®gures 1A, 2A). Ventral surface of anterior peristomial ring appears swollen and glandular (®gure 2B). Pair of crescentic to round black eyes just posterior to collar. Setiger 1 about one-half length of anterior peristomial ring, wider than long; setigers 2±3 each about same length as setiger 1 or slightly longer; setigers 4±8 successively longer than setiger 3, with setiger 8 about four times longer than setiger 1. Setiger 9 slightly longer than setiger 8, with setigers 10±11 each successively shorter than 9. Pygidium about same length as setiger 11, posterior margin slightly tapered, rounded. Pair of round, black pygidial eyes (®gure 1A). Superior thoracic notosetae elongate, narrowly hooded, three to four per fascicle. Inferior thoracic notosetae in setiger 2 elongate narrowly hooded, two per fascicle; setigers 3±8 with pseudospatulate setae (®gure 1C), two per fascicle. Abdominal neuropodia of setigers 9±11 with very elongate, narrowly hooded setae, one to three per fascicle. Thoracic uncini acicular, main fang slender (®gure 1D); large tooth oOEset from mid-line of main fang present, remaining teeth behind main fang slender and slightly decreasing in size away from fang; hood present; four to ®ve uncini per fascicle in straight single rows. Abdominal uncini with six to seven rows of teeth in pro®le, three to four teeth per row (®gure 1E); manubrium about same length as dentate region, slightly expanded proximally; uncini in setigers 9±11 number 14, 20 and 10, respectively. Females with oocytes in setiger 4, males with developing sperm in setigers 4±8. Pigmentation absent on branchial crown and body wall of all specimens. Tubes composed of ®ne silt and detritus. No brooding of young observed.

Etymology. The speci®c epithet refers to the narrow, elongate dorsal lips in the branchial crown.

Remarks. Fabricinuda longilabrum is most similar to F. pseudopalpa Fitzhugh, 1990a in that both have dorsal lips, but lack ventral ®lamentous appendages ( table 1, ®gure 1B; Fitzhugh, 1990a: ®gure 6E). The other four described species of Fabricinuda , F. limnicola ( Hartman, 1951) , F. bikinii ( Hartman, 1954) , F. trilobata ( Fitzhugh, 1983) and F. pseudocollaris Fitzhugh, 1990a , lack dorsal lips and have unbranched, vascularized ventral ®lamentous appendages ( Fitzhugh, 1990a: ®gures 1E, 2E, 5A, 9A, respectively). Fabricinuda longilabrum is readily distinguished from F. pseudopalpa by the following features: (1) the anterior peristomial ring is distinctly longer than wide in F. longilabrum (®gure 2), whereas in F. pseudopalpa length and width are similar ( Fitzhugh, 1990a: ®gures 6A±C, 7); the demarcation of anterior and posterior peristomial rings in F. longilabrum follows that of Fitzhugh (1990a); (2) the dorsolateral collar lobes are consistently small in F. longilabrum (®gure 2A), while in F. pseudopalpa they can range from small and lobe-like to elongate and palp-like ( Fitzhugh, 1990a: ®gures 6A±C, 7); and (3) the body wall of F. longilabrum lacks pigmentation, whereas in F. pseudopalpa the anterior end is light to dark brown ( Fitzhugh, 1990a: 172). Cladistic relationships among Fabricinuda species are presented below.

Fabricinuda longilabrum is only the second described species in the genus from continental shelf depths. Uebelacker (1984) identi®ed specimens as Fabriciola trilobata , subsequently moved to Fabricinuda by Fitzhugh (1990a: 170), from the eastern Gulf of Mexico at depths ranging from 10 to 189 m. Based on her description, the specimens belong to Fabricinuda , but F. trilobata was originally described from intertidal mangrove swamp habitats oOE Belize ( Fitzhugh, 1983). All other described species have been found in the intertidal ( F. limnicola , F. bikinii , F. trilobata , F. pseudopalpa ) or very shallow subtidal ( F. pseudocollaris ). There is, however, an undescribed species, Fabricinuda sp. , discussed below from the same habitat as F. longilabrum .

Fabricinuda longilabrum was identi®ed as `Fabriciola sp. 3’ in the environmental study conducted by Battelle Ocean Sciences. A new species of Pseudofabriciola , P. W laris, described below co-occurs with Fabricinuda longilabrum .