Amphitritides carawa sp. nov.

(Figs 1, 2 A–C, 3)

Material examined. Type series. All type material coll. Cowan Creek, New South Wales, 33º 39' S 151º 10' E, under boulders at low water mark, by P. Hutchings & J. Nogueira, 10th October 2004, fixed in 7% formalin and subsequently washed and transferred to 80% ethanol. Holotype (AM W30724) well preserved, complete specimen, measuring 41 mm in length, 6 mm maximum width anteriorly, with 20 pairs of notopodia, ripe male. Paratypes: paratype 1 (AM W30725) posteriorly incomplete specimen (although several posterior fragments are also inside the vial), with 22 pairs of notopodia, ripe male; paratype 2 (AM W30727), posteriorly incomplete specimen, missing posteriormost segments and pygidium, measuring 25 mm in length, 2.28 mm maximum width anteriorly and with 20 pairs of notopodia; paratype 3 (MZUSP 17359) well preserved, posteriorly incomplete specimen, missing posteriormost segments and pygidium, measuring 53 mm in length, 5 mm maximum width anteriorly, with 21 pairs of notopodia, gravid female, with many oocytes in anterior and mid abdominal segments; paratype 4 (MZUSP 17359), poorly preserved, posteriorly incomplete specimen, measuring 46 mm in length, 3.5 mm maximum width anteriorly, with 19 pairs of notopodia.

Additional material. AM W30723: coll. Smiths Creek, New South Wales, 33° 36' 58" S 151° 11' 20" E, intertidally, 2nd June 2001, 2 individuals both gravid, fixed in 100% alcohol: 45 mm in length, 5 mm maximum width anteriorly, with 21 pairs of notopodia, complete; 25 mm in length, 2.5 mm maximum width anteriorly, with 22 pairs of notopodia, incomplete.

Comparative material examined. Amphitritides gracilis (Grube, 1860): Type material: syntypes: ZMB 5045: 4 specimens, coll. Scilly Islands, off southwest England. Non-type material: AM W 200884: 2 specimens, coll. Wembury Bay, Devon, England, 50° 17' 60” N, 4° 4' 60” W, by P. Gibbs, 26th March 1970.

Amphitritides harpa Hutchings and Glasby, 1988: Type material: holotype: AM W 200344: coll. Eclipse Island, Great Barrier Reef, Queensland, Australia, 18º 46’ S 146º 33’ E; paratype: AM W 200345: coll. One Tree Island, Great Barrier Reef, Queensland, Australia, 23º 30’ S 152º 05’ E.

Amphitritides ithya Hutchings and Glasby, 1988: Type material: holotype: AM W 200338: coll. Port Denison, Queensland, Australia, 20º 03’ S 148º 15’ E; paratype: AM W 200339: coll. West of Topsy Creek, Gulf of Carpentaria, Queensland, Australia, 15º 28.5’ S 140º 53.2’ E. Non-type material: AM W 22421: 4 specimens, 2 of which donated to MZUSP (MZUSP17396), coll. north-east of East Wallabi Island, Houtman Abrolhos, Western Australia, 28° 24' S, 113° 46' 10" E; NTM W2107: 1 specimen, coll. Mangrove Point, Broome, Western Australia, 17°58.5' S 122°14.5' E, 27th September 1984, LWS, by J.R. Hanley, off old jetty pilings; NTM W2794: 1 specimen, coll. East Point, Darwin, Northern Territory, Australia, 12°25' S 130°49.5' E, 18th May 1985, LWS, by J.R. Hanley, under rocks imbedded in mud; NTM W2825: 1 specimen, coll. East Point, Darwin, Northern Territory, 12°25' S 130°49.5' E, 18th May 1985, LWS, by J. Montefiore, under rocks imbedded in mud; NTM W3954: 2 specimens, coll. Cable Beach, Broome, Western Australia, 17°58.3' S 122°11.3' E, 29th September 1984, LWS, by J.R. Hanley, under stones on beach.

Description. Body long, robust, white in life, with red branchiae and bright yellow buccal tentacles, pale after preservation; body distinctly inflated dorsally on anterior segments, with faint segmentation dorsally (Fig. 1 B–C). Prostomium at base of upper lip, basal part lacking eyespots, distal part forming shelf-like tentacular membrane from which numerous buccal tentacles originate (Fig. 1 A–F, H). Peristomium forming lips and continuing laterally from mouth for short extension; upper lip short, hood-like, convoluted, broader than high; lower lip narrow and swollen (Fig. 1 A, D–F, H). Segment 1 dorsally narrow, more developed ventrally, forming protruding lobe below lower lip (Fig. 1 A–F, H). Segments 2–4 with anterior margins forming low, protruding crests laterally and ventrally (Fig. 1 A, C–F, H). Ventral shields on segments 2–15, all smooth, rectangular, wider on segments 2–4, then progressively narrowing; long shield on segment 2, shield on segment 4 shortest, then progressively longer on segments 5–13; from segment 16, mid-ventral shields replaced by stripe extending posteriorly until pygidium (Fig. 1 A, D, G).

Two pairs of short, branching branchiae on segments 2–3, both pairs with short, thick main stem, with dichotomous ramifications starting from close to base and ending with short filaments; first pair originating from middle of segment 2, second pair originating from posterior part of segment 3, at border with segment 4, and aligned slightly laterally to first pair; first pair about twice as large as second pair and measuring less than half of body width (Fig. 1 A–F, H).

Notopodia beginning from segment 4 and extending for 19–22 segments, 20 in holotype. Notopodia short, approximately rectangular, all similar in size, first pair dorsally aligned to following pairs (Fig. 1 A, C, F, H). Notochaetae of both tiers with basally inflated limbation, starting from distal half of chaetae in case of those on posterior tier, and finely denticulate tips (Fig. 2 A–C).

Neuropodia starting from segment 5, as low rectangular ridges slightly raised from surface of body throughout (Fig. 1 A, C–H); abdominal neuropodia close to mid ventral groove (Fig. 1 G), without internal supporting rods (Fig. 3 D). Uncini with short triangular heel, distally pointed prow downwardly directed, dorsal button at about mid-length of distance between base of main fang and tip of prow, and main fang surmounted by 3 rows of secondary teeth (Fig. 3). Uncini arranged in double rows, rows completely separated from each other, with uncini directed beak to beak, from segment 11 until close to pygidium (Fig. 3 C–D).

Nephridial papillae on segments 3 and 6–19, inserted laterally and slightly anteriorly to branchial stem on segment 3, and anteriorly to base of notopodia and aligned to them on segments 6–19 (Fig. 1 A, D–F, H). Pygidium smooth (Fig. 1 G).

Remarks. In addition to A. carawa sp. nov., described above, five other species of Amphitritides are known, which are distinguished from each other mainly by the number of pairs of notopodia, morphology of notochaetae and uncini, segments with nephridial papillae and the position of these papillae (Table 1).

Amphitritides bruneacomata (Ehlers, 1887) differs from A. carawa sp. nov., as it has distally brown buccal tentacles, 27 pairs of notopodia, both pairs of branchiae of similar size, uncini with 2 rows of secondary teeth above main fang, double rows of uncini in a partially intercalated arrangement and nephridial papillae extending until segment 20 (Ehlers 1887; Monro 1933), while A. carawa sp. nov., has yellow buccal tentacles in life, pale after fixation, 19–22 pairs of notopodia, first pair of branchiae about twice the size of second pair, uncini with 3 rows of secondary teeth, double rows of uncini completely separated from each other and nephridial papillae terminating on segment 19 (Table 1).

Amphitritides gracilis differs from A. carawa sp. nov., as it has uncini with 5 rows of secondary teeth above main fang and nephridial papillae on segments 3 and 6-13, inserted between parapodial lobes (Table 1). Amphitritides harpa differs from A. carawa sp. nov., as it has notopodia extending until the posterior body, posterior notochaetae, on both tiers, alimbate with serrated blade at an angle with the shaft, uncini with upwardly directed prow, double rows of uncini in a partially intercalated arrangement and fewer pairs of nephridial papillae, originating between parapodial lobes, at dorsal end of tori, while A. carawa sp. nov., has fewer pairs of notopodia, all notochaetae with basally bulbous limbation and finely serrated tips along the same axis as shaft, double rows of uncini completely separated from each other, uncini with downwardly directed prow and nephridial papillae originating anteriorly to base of notopodia (Table 1).

Amphitritides ithya is very similar to A. carawa sp. nov. in regards to the morphology of notochaetae and uncini. These species differ, however, because A. ithya has prostomial eyespots, nephridial papillae extending only until segment 14 and it is a smaller species, the largest specimens examined measuring up to around 34 mm in length, while the holotype of A. carawa sp. nov., is 46 mm long (Table 1). It could be argued that A. carawa sp. nov. as defined above could represent adult specimens of A. ithya, however those species seem to have well limited ranges of variation for size and number of nephridial papillae and no intermediates between Size: length x width (mm) 13.2 x 1.3 (holotype) 21 x 3 41 x 6 those ranges have been observed. The study of additional non type material of A. ithya varying considerably in size showed that prostomial eyespots may fade with time, but the number of pairs of nephridial papillae is consistent, not dependent on size. For this reason, we consider A. carawa sp. nov., as a separate taxon.

Finally, A. pectinobranchiata is a taxon different from all other taxa currently assigned to Amphitritides and it seems unlikely that it belongs to this genus, however a revision of the genus is beyond the scope of this paper. Amphitritides pectinobranchiata differs from A. carawa sp. nov., in only having 13 pairs of notopodia, notochaetae with narrow limbation, not basally bulbous, abdominal neuropodia forming raised pinnules, uncini arranged in double rows only on segments 10–19 and uncini with 4 rows of secondary teeth and strongly bent posteriorly (Hartmann-Schröder 1965) (Table 1).

Etymology. The specific name “ carawa ” is an Aboriginal word for creek (Endacott 1973) referring to the type locality of Cowan Creek.