Pectinariidae Quatrefages, 1866  

Pectinariidae Quatrefages, 1866

Pectinariidae sp. 1

Voucher. ENDEVOUR: station E4FB.

Diagnosis. Small sized specimen, body conical in shape, voucher complete, 4mm long (including the palelae) and about 0.4mm wide; not in the best condition slightly desiccated.  

Rim of cephalic veil appears smooth or at the best with very shallow indistinct dense cerration. Cephalic veil completely free from operculum, forming a slender triangular lobe around the peristomial palps. Raised opercular margin well developed, smooth. Operculum with 9 pairs of long amber-coloured paleae, with blunt tips. Two pair of slender, elongated tentacular cirri and two pairs of branchiae on segments 3 and 4 present (specimen too dessicated to clearly observed these clearly).

Chaetigers 1 to 3 (segments 5 to 7) with notopodia and notochaetae only. Chaetigers 4 to 17 biramous with both notopodia, neuropodia, and notochaetae and uncini.  Notochaetae from chaetiger 4 include smooth winged capillaries, and capillaries with finely serrated margins. Notochaetae from chaetiger 14 with finely hirsute surfaces. Uncini  forming “paw-like” pattern with irregular rows of small teeth above the main. Posterior scaphe and abdomen distinctly separated. Posterior 5 segments fused to form scaphe. Scaphe slightly longer than broad, with narrow elongated dorsal papilla. Scaphal hooks present, 6 pairs, stout, distally blunt.

Remarks.  Hutchings and Peart (2002) provided a review of genera of Pectinariidae, with 5 valid genera.  The combination of the characters observed in Falkland Island specimens (see Table 1. below) differs from the know genera, suggesting it may represents a new genus (or need to amend generic definition). It is affiliated most closely with genus Petta Malmgren, 1866 in having smooth cephalic veil, smooth dorsal opercular rim and 14 pairs of neuropodia, however its scaphe is distinctly separated from the abdomen. Further, teeth of uncini are not neatly arranged in 1 (or 2 as common in some genera) row, but instead from “paw-like” pattern with irregular rows of small teeth above the main fang as known in Ampharetidae (SEM is needed to fully establish the form of uncini).  Ideally, a greater number of well-preserved specimens need to be examined in order to diagnose this genus, as it is not clear if some variation observed here is an artefact of desiccation of the voucher specimen. At present, we suggest to assign this specimen to morphospecies Pectinariidae sp. 1.

Table 1. Comparison of characters separating genera of Pectinariidae, including specimen Pectinariidae sp. 1 from Falkland Islands (modified from Hutchings and Peart, 2002).

REFERENCES

Hutchings, P. and Peart, R., 2002. A review of the genera of Pectinariidae (Polychaeta) together with a description of the Australian fauna. RECORDS-AUSTRALIAN MUSEUM, 54(1), pp.99-127.