Chrysopetalidae, Ehlers, 1864

Muir, Alexander I. & Bamber, Roger N., 2008, New polychaete (Annelida) records and a new species from Hong Kong: the families Polynoidae, Sigalionidae, Chrysopetalidae, Pilargiidae, Nereididae, Opheliidae, Ampharetidae and Terebellidae, Journal of Natural History 42 (9 - 12), pp. 797-814 : 801-803

Chrysopetalidae sp. indet.

Material

One specimen, Kei Chau (Steep Island) Cave, station B, at a depth of 11.1 m.

This specimen has a long body covered in flattened paleae, which are darker and wider than those of Chrysopetalum ehlersi (see above). It agrees well with the generic definition of Bhawania in Fauchald (1977), but unfortunately the head is missing. As 12 genera are now recognised (as opposed to the four known to Fauchald 1977) and as the structure of the anterior end is necessary for their identification, this specimen is only identified to family level here.

A key is provided below for the identification of the chrysopetalid genera of the world and two species which do not fit into a currently recognised genus. It is based on the key in (and uses characters defined in) Perkins (1985), with the new genera published since that date added.

Note 1. Vigtorniella Kiseleva, 1996 , is the replacement name for Victoriella Kisseleva, 1992 (which is preoccupied). The characters used in the key for this genus (which was published in Russian) were taken from Dahlgren (1996).

Note 2. Strepternos Watson Russell in Bhaud and Cazaux (1987) was more fully described by Watson Russell (1991).

1. Notopodia of middle segments with paleae, or with paleae and at least one spine............................................. 4

- Notopodia of middle segments with spines only.................. 2

2. Compound neurochaetae with unidentate blades; appendage absent on posterior rim of mouth (ventral cirri of segment 1 may approach each other to form analogous structures).......................... 3

- Compound neurochaetae with bidentate blades; appendage present on posterior rim of mouth.... ‘‘ Chrysopetalum ’’ caecum Langerhans, 1880

3. Median antenna present; single pygidial projection present......................................... Dysponetus Levinsen, 1879

- Median antenna absent; paired pygidial cirri present............................................. Vigtorniella Kiseleva, 1996

4. Lateral and midline groups of notochaetae of middle segments consisting of spines only................. Hyalopale Perkins, 1985

- Lateral and midline groups of notochaetae of middle segments consisting of paleae or paleae and at least one spine............... 5

- Midline group notochaetae absent, lateral group paleae present..... 11

5. Four pairs of cirri on the first two segments. Chrysopetalum Ehlers, 1864

- Three pairs of cirri on the first two segments.................... 6

6. Middle group paleae of middle segments produced in fan-shaped groups from one or two developmental centres........................ 7

- Middle group paleae of middle segments produced separately, forming broad imbricate row..................................... 9

7. Caruncle distinct; middle group paleae of middle segments produced from two developmental centres in fan-shaped rows, one behind the other; compound neurochaetae of middle segments with spinigerous blades.................. ‘‘ Paleanotus ’’ schmardai Mileikovsky, 1962

- Caruncle absent or greatly reduced; middle group paleae of middle segments produced in single fan-shaped, imbricate row from single developmental centre; compound neurochaetae of middle segments with falcigerous blades....................................... 8

8. Caruncle absent; middle group paleae of middle segments nearly symmetrical, with symmetrical tips.......... Treptopale Perkins, 1985

- Caruncle/nuchal fold, if present, reduced to flattened structure; middle group paleae of middle segments distinctly asymmetrical, with margins convex laterally and concave medially...... Paleanotus Schmarda, 1861

9. Caruncle/nuchal fold and mouth cover present; up to 55 segments; dorsal cirri not retractile within cirrophores; midline group paleae of middle segments very stout; most lateral group paleae similar to middle group paleae but curved oppositely; paleae silver to gold...................................... Arichlidon Watson Russell, 1998

- Caruncle and mouth cover absent; adults with over 100 segments; dorsal cirri retractile within cirrophores; midline group paleae of middle segments broad but thin; lateral group paleae distinctly different from middle group paleae; paleae golden-brown..................... 10

10. Adults with a maximum of 127 segments; paleae with erosive tips; comparatively discrete, semicircular, glandular nuchal fold..................................... Paleaequor Watson Russell, 1986

- Adults with a maximum of more than 300 segments; paleae without erosive tips; thick, fleshy, projecting nuchal ridge................................................ Bhawania Schmarda, 1861

11. Segment 2 with two pairs of tentacular cirri and notochaetae; mid-body compound falcigerous neurochaetae with bifid tips............... 12

- Segment 2 with dorsal cirri (ventral cirri absent), notochaetae and neurochaetae; mid-body compound falcigerous neurochaetae with thick unidentate tips. Strepternos Watson Russell in Bhaud and Cazaux (1987)

12. Middle group notochaetae broad symmetrical paleae in one row; palps ovoid with distal filiform process......... Thrausmatos Watson, 2001

- Middle group notochaetae slender, curved, with spines, originating from discrete anterior and posterior rows; palps cylindrical, very elongate............................... Acanthopale San Martín, 1986