Pseudoaugeneriella spongicola, Giangrande, Adriana, Licciano, Margherita & Gambi, Maria Cristina, 2007

Giangrande, Adriana, Licciano, Margherita & Gambi, Maria Cristina, 2007, A collection of Sabellidae (Polychaeta) from Carrie Bow Cay (Belize, western Caribbean Sea) with the description of two new species, Zootaxa 1650, pp. 41-53 : 47-50

Pseudoaugeneriella spongicola sp. nov.

Figure 3

Material examined. Type material: Holotype, found inside the sponge Ircinia cf strobilina from 1 m, West Bay of Twin Cays (sample CBC-KF 1008) collected November, 2005. MNCN catalog number 16.01/11019. Paratypes: 2 specimens from the same site USNM catalog number 1102754. 8 specimens from the same site at PCZL.

Description. Holotype complete with 8 thoracic and 3 abdominal chaetigers. Branchial crown length 0.80 mm, body length 2 mm, maximum width 0.35 mm at chaetiger 4. Body slightly inflated in the mid part ( Fig. 3 A). Branchial crown with 3 pairs of radioles, distal ends filamentous, same length as pinnules, all terminating slightly below level of radioles. Dorsal lip erect, broadly rounded, distinct from radioles ( Fig. 3 C); ventral lip-like process present at base of proximalmost pinnules of ventral radioles ( Fig. 3 C). Vascularized ventral filamentous appendages unbranched, shorter than radioles (about 0.20 mm), and wider than pinnules, surface slightly wrinkled and with large blood vessel inside ( Fig. 3 A, B,C). Branchial hearts present. Anterior margin of anterior peristomial ring, low ridge dorsally and laterally. Collar developed as ventral quadrangular lobe, about twice as long as remainder of anterior ring ( Fig. 3 A). Annulation visible only dorso-laterally. Middorsal medial lobe dorsal to mouth, high, triangular ( Fig. 3 B).

One pair of small reniform eyes in anterior half of posterior peristomial ring. Pygidium with one pair of large reniform eyes.

Superior thoracic notochaetae elongate, narrowly hooded, 2 per fascicle; inferior thoracic notochaetae in chaetiger 2 and 7–8 also narrowly-hooded, but shorter, 2 present ( Fig. 3 D). Chaetigers 3–6 with 2 pseudospathulate chaetae ( Fig. 3 E). Abdominal neuropodia of chaetiger 9–11 with elongate, narrowly-hooded chaetae, 1–2 per fascicle ( Fig. 3 H). Thoracic acicular uncini with single large tooth over main fang, followed by series of smaller teeth ( Fig. 3 F); hood present, 6 per fascicle in irregular single row. Abdominal uncini with 6 rows of teeth in profile, 3–4 teeth per row, manubrium twice as long as dentate region (Fig, 3G). Uncini in Remarks. The genus Pseudoaugeneriella was erected by Fitzhugh (1998), with the species P. unirama from Japan. The author pointed out that the genus is similar to Augeneriella Banse, 1957 , and differs only in the unbranched nature of the ventral appendages. These filaments, however, in Augeneriella are initially unbranched in the ontogeny (see for example A. hummelincki Banse, 1957 ). Therefore P. u n i r a m a could be considered as the most plesiomorphic taxon within the genus Augeneriella , but in order to maintain its monophyly, Fitzhugh preferred to erect a new genus.

Subsequently, another two species were described as belonging to this genus, P. brevirama Fitzhugh, 1999 and P. nigra (= Fabricia nigra ) (Langerhans, 1880) from the Canary Islands. The difference among these species is mainly in the length of vascularized appendages, which are of the same length of radioles in P. unirama , about 50% of the length of radioles in P. b re v i r a m a, and about 25% in P. n i g r a ( Bick, 2004). This latter author discussed the variability of the feature within P. nigra specimens, where the length ranges from the 18% to 38% of the length of radioles. This variability was also observed within the species here described, with the ventral filamentous appendage varying from 16% to 25% of the length of radioles, with a medium length of about of 20%. This means that ventral filamentous appendages are relatively shorter in P. spongicola than in the other described species, including P. nigra . The new species can be distinguished from P. n i g r a also by the absence of pigmentation, and in the number of thoracic and abdominal uncini, which, however, Bick (2004) found to be size dependent within the same species. Pseudoaugeneriella spongicola differs from P. unirama and P. brevirama also in the shape of the ventral collar lobe and in the length of the manubrium of the abdominal uncini, which in this species is 1.5 times longer than the dentate region. Bick (2004) in his redescription of P. n i g r a, reports that the manubrium is twice as long as the dentate region, however he does not illustrate this. In contrast, Fitzhugh (1990), who examined Langerhans’ material of Fabricia nigra from Madeira, records the manubrium of abdominal uncini being as long as the dentate region.

Lastly, it must be stressed that P. spongicola shows some similarities to Augeneriella hummelinki , especially in the shape of ventral collar lobe, but differing in the number of teeth of abdominal uncini, which are larger in A. hummelinki . As far as the nature of ventral filamentous appendages, it must be stressed that among the 11 P. spongicola specimens examined, some were large and ripe (including the holotype), but all, including the smaller ones, have unbranched appendages. The length of the unbranched appendages does not appear to be correlated to the size of the worms, and in addition some individuals are asymmetrical in their development, differing in length on the left and right hand side of the animal.

Type locality: Carrie Bow Cay, Belize

Etymology: The species was named after the habitat where it occurs.

Figures

FIGURE 3. Pseudoaugeneriella spongicola sp. nov. A) entire worm ventral view, B) anterior end dorsal view, C) crown section showing the dorsal and ventral lips, D) thoracic elongate narrowly hooded chaeta, E) pseudospatulate chaeta, F) thoracic uncinus, G) abdominal uncinus, profile and frontal view, H) abdominal chaeta. dl = dorsal lip; vl = ventral lip.