Terebellides

Key to intertropical South Atlantic species of Terebellides

The following key comprises the eight species described here, together with those previously described or recorded from Western Atlantic (Williams, 1984; Solís-Weiss et al., 1991; Garraffoni & Lana, 2003; Díaz-Díaz & Liñero- Arana, 2003), Caribbean Sea (Williams, 1984) and southern Brazil (Bremec & Elías, 1999; Garraffoni & Lana, 2003; Schüller & Hutchings, 2012). No material of these species was examined; characters were obtained from bibliography. It is mostly based on branchial characters, number of thoracic chaetigers and location of geniculate chaetae, but also on the thoracic colouration, presence of dorsal hump, and length of thoracic notochaetae.

Terebellides banalis Schüller & Hutchings, 2012 and Terebellides bulbosa Schüller & Hutchings, 2012 are not considered here because the original descriptions do not provide detailed information on branchiae. In T. banalis, only one type specimen has branchiae, consisting of a stout stem with four very small and stout branchial lobes (Schüller & Hutchings, 2012: Fig. 7A, 8B), suggesting it may be a juvenile. The species is characterized by having well-developed S2, ventrally wider than S3 (TC1), and by TC6 cane-shaped geniculate chaetae (Schüller & Hutchings, 2012: Fig. 8E). Terebellides bulbosa bears a branchial stem lacking well defined lobes and shows very large lappets in the first four chaetigers, followed by a series of laterally expanded segments before a typical Terebellides - like posterior thorax (Schüller & Hutchings, 2012: Fig. 10).

1. First unciniger in TC5; 17 or 18 thoracic uncinigers.......................................................... 2

- First unciniger in TC6; 18 thoracic uncinigers............................................................... 3

2. 17 thoracic uncinigers............................................................. T. anguicomus Müller, 1858

- 18 thoracic uncinigers....................................................... T. crux Schüller & Hutchings, 2013

3. Anterior dorsum with a distinct hump on TC7............................................................... 4

- Anterior dorsum smoothly curved........................................................................ 5

4. Ventral branchial lobes more slender than dorsal ones; lateral lappets from TC3 to TC5.................................................................................. T. carmenensis Solís-Weiss, Fauchald & Blankensteyn, 1991

- Both branchial lobes similar in size; lateral lappets from TC5 to TC7..................... T. totae Bremec & Elías, 1999

5. TC1 to TC5 ventrally whitish (Fig. 33 A–B)........................................... Terebellides ramili sp. nov.

- TC1 to TC4 similar in colour as following chaetigers......................................................... 6

6. Anterior branchial lobe well developed.................................................................... 7

- Anterior branchial lobe absent or much shorter than posterior lobes............................................. 13

7. Branchial stem long, about as long as posterior dorsal lobes (Fig. 21A)................. Terebellides kirkegaardi sp. nov.

- Branchial stem much shorter than posterior dorsal lobes....................................................... 8

8. TC1 notopodia and notochaetae much more developed than following........................................... 9

- TC1 notopodia and notochaetae similar to following........................................................ 10

9. Ventral posterior branchial lobes length about 10% of dorsal ones, located after the fusion line of the latter (Fig. 12A, 13A)............................................................................ Terebellides congolana sp. nov.

- Ventral posterior branchial lobes length about 50% of dorsal ones, emerging directly from the branchial stem (Fig. 12B, 16C)............................................................................. Terebellides fauveli sp. nov.

10. Thoracic notochaetae almost as long as thoracic width; TC1 lateral lappet forming a fan-like dorsal expansion (Fig. 21B, 25 B–C)..................................................................... Terebellides longiseta sp. nov.

- Thoracic notochaetae much shorter than thoracic width; TC1 lateral lappet not forming a fan-like dorsal expansion....... 11

11. TC1 notochaetae short, scarce................................. T. lanai Solís-Weiss, Fauchald & Blankensteyn, 1991

- TC1 notochaetae similar to following ones................................................................ 12

12. 20–26 abdominal chaetigers.......................... Terebellides parvus Solís-Weiss, Fauchald & Blankensteyn, 1991

- At least 30 abdominal chaetigers...................................................... T. klemani Kinberg, 1867

13. Branchial lobes neither fused nor comma-shaped........................................................... 14

- Branchial lobes at least partially fused, comma-shaped....................................................... 19

14. Branchial posterior ventral lobes with long terminal filament (Fig. 28A, 30 A–B)............. Terebellides nkossa sp. nov.

- Branchial posterior ventral lobes lacking long terminal filament............................................... 15

15. Anterior thoracic chaetigers narrow, laterally expanded like a partially compressed accordion.................................................................................... Terebellides concertina Schüller & Hutchings, 2012

- Anterior thoracic chaetigers different..................................................................... 16

16. Lower buccal lip and tentacular membrane greatly expanded.................................................. 17

- Lower buccal lip and tentacular membrane different......................................................... 18

17. Branchial lobes completely free from each other, bearing few and loose lamellae; upper lip of tentacular membrane small................................................................... Terebellides diva Schüller & Hutchings, 2012 Branchial lobes not fused but well defined, with numerous and well-packed lamellae; upper lip of tentacular membrane much developed (Fig. 35 A–B)................................................................... Terebellides sp. 1

18. Pygidium with two prominent lateral papillae.......................... Terebellides gingko Schüller & Hutchings, 2012

- Pygidium lacking papillae......................................... Terebellides sepultura Garraffoni & Lana, 2003

19. Branchial posterior ventral lobes similar in shape to dorsal ones, about half longer, located at base of dorsal ones (Fig. 2B, 8E); thoracic uncini capitium with first row of 5–6 teeth, similar in size to following ones (Fig. 10 A–B)................................................................................................. Terebellides augeneri sp. nov.

- Branchial posterior ventral lobes much shorter than dorsal ones................................................ 20

20. Branchial posterior ventral lobes near distal end of dorsal ones (Fig. 2A, 4A, 5A); thoracic uncini capitium with first row of 1–2 teeth, much bigger than following (Fig. 7A).......................... Terebellides africana Augener, 1918 stat. prom.

- Branchial posterior ventral lobes emerging at base of dorsal ones.......... Terebellides malvinensis Bremec & Elías, 1999