Pseudofabriciola, Fitzhugh, 1990

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 : 907-911

Pseudofabriciola ®laris n. sp.

(®gures 6±8; tables 4, 6)

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 2007 , sta. EPB-III-D-3 . PARATYPES: LACM-AHF 2008 , sta. BWC-I-D-2 (two specimens) ; LACM-AHF 2009 , sta. BWC-I-D-3 (one specimen) ; LACM-AHF 2010 , sta. BWC-III-B-1 (two specimens) ; LACM-AHF 2011 , sta. BWC-III-C-1 (two specimens) ; LACM-AHF 2056 , sta. BWC-III-C-2 (one specimen) ; LACM-AHF 2012 , sta. BWC-III-C-3 (three specimens) ; LACM-AHF 2013 , sta. BWC-III-D-1 (two specimens) ; LACM-AHF 2014 , sta. BWC-III-D-2 (one specimen) ; LACM-AHF 2015 , sta. BWC-III-D-3 (two specimens) ; LACM-AHF 2016 , sta. EPB-I-B-3 (one specimen) ; LACM-AHF 2017 , sta. EPB-I-D-1 (two specimens) ; LACM-AHF 2018 , sta. EPB-III-C-2 (one specimen) ; LACM-AHF 2019 , sta. EPB-III-C-3 (one specimen) ; LACM-AHF 2020 , sta. EPB-III-D-1 (two specimens) ; LACM-AHF 2021 , sta. EPB-III-D-3 (®ve specimens) ; LACM-AHF 2022 , sta. EWK- I-C-3 (two specimens) ; LACM-AHF 2023 , sta. EWK-I-D-1 (four specimens) ; LACM-AHF 2024 , sta. EWK-I-D-2 (one specimen) ; LACM-AHF 2025 , sta. EWK- I-D-3 (®ve specimens) ; LACM-AHF 2033 , sta. EWK-III-C-1 (one specimen) ; LACM-AHF 2026 , sta. EWK-III-C-2 (one specimen) ; LACM-AHF 2027 , sta. EWK- III-D-1 (one specimen) ; LACM-AHF 2028 , sta. EWP-I-C-1 (three specimens) ; LACM-AHF 2029 , sta. EWP-I-D-1 (two specimens) ; LACM-AHF 2030 , sta. EWP- I-D-2 (one specimen) ; LACM-AHF 2057 , sta. EWP-I-D-3 (one specimen) ; LACM- AHF 2031 , sta. EWP-III-D-1 (one specimen) ; LACM-AHF 2032 , sta. EWP-III-D-3 (two specimens) ; LACM-AHF 2034 , sta. PCP-I-A-1 (one specimen) ; LACM-AHF 2058 , sta. PCP-I-B-1 (one specimen) ; LACM-AHF 2035 , sta. PCP-I-B-2 (two specimens) ; LACM-AHF 2036 , sta. PCP-I-B-3 (one specimen) ; LACM-AHF 2037 , sta. PCP-I-C-1 (three specimens) ; LACM-AHF 2038 , sta. PCP-I-C-3 (one specimen) ; LACM-AHF 2039 , sta. PCP-I-D-1 (one specimen) ; LACM-AHF 2040 , sta. PCP-I- D-3 (two specimens) ; LACM-AHF 2041 , sta. PCP-III-C-1 (one specimen) ; LACM- AHF 2042 , sta. PCP-III-C-2 (one specimen) ; LACM-AHF 2043 , sta. PCP-III-C-3 (two specimens) ; LACM-AHF 2044 , sta. PWE-I-B-3 (one specimen) ; LACM-AHF 2045 , sta. PWE-I-C-2 (one specimen) ; LACM-AHF 2046 , sta. PWE-I-C-3 (one specimen) ; LACM-AHF 2047 , sta. PWE-III-B-1 (four specimens) ; LACM-AHF 2048 , sta. PWE-III-C-1 (one specimen) ; LACM-AHF 2049 , sta. PWE-III-C-3 (one specimen) ; LACM-AHF 2050 , sta. PWE-III-D-2 (one specimen) ; LACM-AHF 2051 , sta. Control-1-3 (two specimens) ; LACM-AHF 2052 , sta. Control-2-2 (one specimen) ; LACM-AHF 2053 , sta. Control-2-3 (one specimen) ; LACM-AHF 2054 , sta. Control-3-1 (one specimen) ; LACM-AHF 2055 , sta. Control-5-3 (one specimen) .

Description. Holotype incomplete (branchial crown missing), with eight thoracic and three abdominal setigers. Total length 4.80 mm, maximum width 0.10 mm (paratype with branchial crown length of 0.50 mm and combined thorax/abdomen length of 2.50 mm). Body distinctly thread-like, uniform width throughout except for slight tapering in abdomen (®gure 6A; but see Specimen variation below). Branchial crown (in paratypes) with three pairs of radioles, distal ends elongate, ®lamentous, same width as pinnules. Dorsalmost radioles each with four pairs of pinnules, ventralmost radioles with two pairs of pinnules, all terminating at about same height as ends of radioles. Dorsal lips poorly developed (®gure 6B); low, broadly rounded, forming narrow shelf-like process; ventral lips absent. Vascularized, ventral ®lamentous appendages absent. Dorsal margins of branchial lobes not fused to one another; lobes very elongate, narrowing proximally to short, peduncle-like stalk (®gure 6B). Branchial hearts present but indistinct. Conical structure dorsal to mouth low. Anterior margin of anterior peristomial ring as well-developed, entire, membranous collar. Mid-dorsal collar margin a membranous, triangular lappet, extending well beyond lateral and ventral collar margins (®gures 6A, 7; but see Specimen variation below); lappet distinct from remainder of collar by pair of V-shaped dorsolateral incisions; posterolateral margins of lappet overlap lower lateral collar margins. Middorsal collar lappet about three times longer than remainder of collar, about same length as posterior peristomial ring; lappet surface(?) with faint, slightly concentric lines (®gure 7A, C). Lateral and ventral collar margins entire, even in height and thickness, about one-third length of posterior peristomial ring (®gure 7B, C). Annulation between collar and posterior peristomial ring only visible ventrally. Demarcation between anterior and posterior peristomial rings not visible. One pair of reddish-brown eyes in posterior peristomial ring (®gures 6A, 7A, B). All thoracic setigers longer than wide; setiger 1 about one-third longer than posterior peristomial ring; setiger 2 slightly shorter than setiger 1, with setigers 3±6 each successively longer, with setiger 8 nearly four times longer than setiger 1. Setiger 9 about twothirds length of 8, with setigers 10±11 successively shorter. Pygidium slightly longer than setiger 11, tapered posteriorly (but see Specimen variation below). Pygidial eyes poorly developed, with diOEuse, light brown pigmentation (®gure 6A, C). Superior thoracic notosetae elongate, narrowly hooded, two to three per fascicle. Inferior thoracic notosetae in setigers 2±8 also narrowly hooded but shorter, one to two per fascicle. Abdominal neurosetae very elongate, narrowly hooded, one per fascicle. Thoracic uncini acicular, main fang slender (®gure 6D); single large tooth oOEset from mid-line of main fang, teeth behind large tooth successively smaller in size; hood present; two to four uncini per fascicle, in straight rows. Abdominal uncini with seven to eight rows of teeth in pro®le, three to four teeth per row (®gure 6E); manubrium about 1.5 times longer than dentate region, slightly expanded proximally; uncini from setigers 9±11 number 12, 13 and 10, respectively. Anus midventral, along anterior margin of pygidium (®gure 6C). Distribution of male and female gametes not determined. Body wall pigmentation absent. Tubes composed of very thin, translucent inner mucoid layer covered with thin layer of ®ne silt and detritus. No brooding of young observed.

Specimen variation. Some specimens exhibit distinct morphological variation relative to the holotype. This variation includes shape of the mid-dorsal collar lobe and lateral incisions, overall body shape, and shape of the ventrum of setiger 11.

The mid-dorsal collar lobe ranges from distinctly triangular, as seen in the holotype (®gures 6A, 7), to broadly rounded (®gure 8). Consistent with this variation in lobe shape, the dorsolateral notches can range from narrowly V-shaped as in the holotype (®gures 7B, 8A) to broadly V-shaped (®gure 8B, C). In those specimens exhibiting a broad mid-dorsal collar lobe, faint concentric lines on the lobe (e.g. ®gure 7A, C) are absent. Correlated with the broadly rounded collar lobe condition, specimens also tend to have relatively shorter and wider bodies, suggesting that contraction inūences collar shape to some extent.

Those specimens with a broad collar lobe and contracted body commonly have what appears to be a small raised area on the ventrum of setiger 11. Upon close inspection, this raised area actually consists of two slightly oblong elevations on either side of the faecal groove (®gure 6C).

Etymology. The speci®c epithet refers to the thread-like body typical of most members of this species.

Remarks. Pseudofabriciola W laris has greatest similarities to P. W lamentosa ( Day, 1963), P. so X a, P. peduncula and P. rousei n. sp. in that each has the combination of an entire mid-dorsal collar margin, smooth mid-dorsal collar surface, and one pair of dorsolateral collar notches (e.g. ®gures 5A, 7, 8; table 4). With the exception of P. W lamentosa, for which dorsal lip shape is unknown ( Fitzhugh, 1991b), each of these species also has dorsal lips as low, narrow ridges, but this is not unique to this group of species. One of the most consistent and diagnostic features of P. W laris is the presence of light reddish-brown to light brown peristomial and pygidial eyespots. Other species of Pseudofabriciola have black peristomial and pygidial eyespots.

Pseudofabriciola W laris is one of the few species known to exhibit substantial morphological variation. A notable exception is the variability in P. longipyga described by Fitzhugh and Simboura (1995). Given the number of specimens of P. W laris available for study, and the range of variation in collar shape, overall dimensions of thoracic and abdominal setigers, and the ventral elevations on setiger 11, it appears that this variation can be accounted for by way of specimen contraction, either prior to or as a result of the act of specimen preservation. There appears to be su cient overlap in the variability of these features to prevent questionable identi®cation of this species.

Pseudofabriciola W laris co-occurs with the new species, Fabricinuda longilabrum , as well as Fabricinuda sp. Most of the specimens were identi®ed as `Fabriciola sp. 1’ in the environmental study conducted by Battelle Ocean Sciences.