Sabellinae

Murray, Anna & Rouse, Greg W., 2007, Two new species of Terebrasabella (Annelida: Sabellidae: Sabellinae) from Australia, Zootaxa 1434, pp. 51-68 : 52-53

Sabellinae Latreille

Terebrasabella Fitzhugh & Rouse, 1999 , emended

Terebrasabella Fitzhugh & Rouse, 1999: 358 –359.

Type species: Terebrasabella heterouncinata Fitzhugh & Rouse, 1999 .

Diagnosis. Small-bodied species with eight thoracic and three abdominal chaetigers. Branchial crown with two pairs of radioles, pinnules pectinately arranged. Palmate membrane, radiolar flanges and radiolar eyes absent. Dorsal lips elongate with radiolar appendages. Ventral lips, parallel lamellae, and ventral sacs absent. Branchial skeleton present, with two rows of cells. Branchial lobes fused along dorsal midline. Ventral margins of branchial lobes with ventral basal flanges. Anterior peristomial ring indistinct; separation of anterior and posterior peristomial rings indistinguishable. Peristomial and pygidial eyespots absent. Posterior peristomial ring collar present, incised mid-dorsally and ventrally. Glandular ridge in chaetiger two absent. Thoracic notochaetae broadly-hooded capillaries (sensu Fitzhugh 1989), arranged in two rows, superior chaetae longer than those in inferior row. Two or three types of thoracic neuropodial uncini present in chaetigers 2–8. Uncini in chaetiger 2 either 2–4 long-handled uncini with small breast (= acicular), with a main fang surmounted by a series of homodont or heterodont teeth, or 1–2 acicular uncini which have a large gap between the large main fang and the semicircle of smaller distal teeth, with one pair slightly larger than the other teeth in the crest (=“palmate”sensu Jones 1974); uncini of chaetigers 3–6 acicular, similar to the hetero- or homodont uncini present in chaetiger 2; breast of uncini either a small swelling or moderately well-developed. Uncini in chaetigers 7–8, Z-shaped with breast and handle (= avicular), all teeth uniform in size and arranged in narrow elongate rasp-shaped rows; breast well-developed; handles of medium length. Companion chaetae present in neuropodia of chaetigers 2–6, absent in chaetigers 7-8. Abdominal notopodial uncini in chaetigers 9–11 acicular, either with distinct main fang surmounted by series of hetero- or homodont teeth, or a similar smaller version of the “palmate” uncinus of chaetiger 2; breast poorly- to well-developed. Abdominal neurochaetae narrowly-hooded capillaries. Simultaneous hermaphrodites; direct-developing young brooded in burrow.

Remarks. This diagnosis is slightly altered from that of Fitzhugh and Rouse (1999). Fitzhugh (2003) argued for a reinterpretation of the dorsal lips of sabellids and that Terebrasabella has radiolar appendages. This is accepted here. Also, after examination of T. heterouncinata specimens we must conclude that the description of the superior thoracic capillary chaetae as “narrowly-hooded” in Fitzhugh & Rouse (1999), ( Figs 6 A,B), is not an accurate reflection of the shape, as all thoracic capillary notochaetae appear to have distinct ‘bilateral’ swelling of the hood, arising either side above the handle, the more elongate superior ones as well as the shorter inferior chaetae. Specimens of T. hutchingsae sp. nov., and T. fitzhughi sp. nov., also possess the same chaetae. This is seen particularly well under SEM examination (see Fig. 3 C). We propose that these chaetae are more accurately described as “broadly-hooded” (sensu Fitzhugh, 1989, Fig, 22E,F). The variability of shape in the uncini of chaetiger two across the three Terebrasabella spp. is reflected in the diagnosis.

Figures

FIGURE 3. Terebrasabella hutchingsae sp. nov., S. E. M. photographs. AM W 29460 A. Anterior end, lateral view, radioles missing. B. Anterior end, dorsal view. C. Inferior and superior thoracic notochaetae. D. Large neurochaetal “ palmate ” uncinus from 2 nd chaetiger, shown from above. E. Companion chaeta and 2 neurochaetal uncini from thoracic chaetiger 3. F. Companion chaeta and a neurochaetal uncinus from thoracic chaetiger 5.

FIGURE 6. Terebrasabella fitzhughi sp. nov., chaetae (specimen destroyed for chaetal drawings). A. Thoracic superior notochaeta, chaetiger 1. B. Thoracic inferior notochaeta, chaetiger 1. C. Thoracic notochaeta, chaetiger 7. D. Abdominal neurochaeta. E. Companion chaeta, chaetiger 3. F. Neurochaetal uncinus, thoracic chaetiger 3. G. Thoracic neurochaetal uncinus, chaetiger 7. H. Abdominal notochaetal uncinus, chaetiger 10. Scales: A – H = 0.01 mm.