Terebellides longicaudatus Hessle, 1917

Parapar, Julio & Moreira, Juan, 2008, Revision of three species of Terebellides (Polychaeta: Trichobranchidae) described by C. Hessle in 1917 from the Southern Ocean, Journal of Natural History 42 (17 - 18), pp. 1261-1275 : 1263-1268

publication ID	https://doi.org/ 10.1080/00222930801989997
persistent identifier	https://treatment.plazi.org/id/AE0C8782-FFB0-FFC4-8DDB-FB97FBAEFD7B
treatment provided by	Felipe
scientific name	Terebellides longicaudatus Hessle, 1917
status

Treatment

Terebellides longicaudatus Hessle, 1917 View in CoL

( Figures 1–4 View Figure 1 View Figure 2 View Figure 3 View Figure 4 )

Terebellides longicaudatus Hessle 1917:139 View in CoL , plate I, figure 17, Textfigure 30.

Type material

Swedish Museum of Natural History, Stockholm. SMNH 540 View Materials ( South Georgia, mouth of Cumberland Bay , 252–310 m depth, 54 ° 11 9 S; 36 ° 18 9 W, grey clay, some stones, SSPE, st. 34; one spec.) GoogleMaps , SMNH 598 View Materials ( South Georgia, Cumberland Bay , Antarctic Bay, 250 m depth, 54 ° 12 9 S; 36 ° 50 9 W, SSPE, st. 20; one spec.) GoogleMaps , SMNH 6625 View Materials ( South Georgia, Cumberland Bay , off May Bay, 75 m depth, 54 ° 17 9 S; 36 ° 28 ° W, clay, algae, SSPE st. 22; three specs.) GoogleMaps , SMNH 6626 View Materials ( SSPE st. 22; one spec.; HOLOTYPE) , SMNH 6627 View Materials ( SSPE st. 22; one spec.) , SMNH 6628 View Materials ( SSPE st. 22; one spec.) , SMNH 6629 View Materials ( South Georgia, Cumberland Bay , outside Grytviken, 95 m depth 54 ° 22 9 S; 36 ° 27 9 W, clay, SSPE st. 24; two specs.) GoogleMaps , SMNH 6630 View Materials ( SSPE st. 34; one spec.) , SMNH 6631 View Materials ( SSPE st. 34; seven specs.) , SMNH 6632 View Materials ( SSPE st. 34; two specs.) , SMNH 6633 View Materials ( SSPE st. 34; one spec.) , SMNH 6634 View Materials ( SSPE st. 34; one spec.) , SMNH 6635 View Materials ( SSPE st. 34; one spec.) , SMNH 6636 View Materials ( SSPE st. 34; five specs.) , SMNH 6637 View Materials ( SSPE st. 34; one spec.) , SMHN 6638 ( SSPE st. 34; three specs.) .

Additional material

British Museum of Natural History, London. South Georgia, Antarctica. NHM 1930.10.8.2163–65 (two specs.), NHM 1930.10.8.2167–70 (three specs.), NHM 1930.10. 8.2234 (one spec.), NHM 1930.10.8.2236–39 (six specs.), NHM 1930.10.8.2525 (one spec.) .

United States National Museum, Washington. Weddell Sea , Antarctica. USNM 47076 View Materials ( USCGC Glacier, cr. 2, st. 27; 64 ° 46.2 9 S; 41 ° 30.1 9 W, 4575 m, March 19, 1969, one spec.), USNM 47075 View Materials ( USCGC Glacier, cr. 2, st. 21; 73 ° 52 9 S; 31 ° 18 9 W, 2288 m, March 13, 1969, one spec.) GoogleMaps .

Type locality

South Georgia Island, Cumberland Bay , off May Bay, 75 m depth, 54 ° 17 9 S 036 ° 28 9 W ( Antarctica) GoogleMaps . Clay, algae.

Description (based on holotype)

Complete specimen of 55 mm in length and 4 mm in width; body tapering posteriorly with segments increasingly shorter and compacted towards pygidium ( Figure 1A View Figure 1 ). Prostomium compact; tentacular membrane surrounding the mouth and provided with one type of oral tentacles with expanded ciliated tips ( Figure 1B View Figure 1 , 2B View Figure 2 ). First segment forming an expanded structure (‘‘lower lip’’) below peristomium. Eyespots absent. Branchiae arising as single structure from segments 3–4 ( Figure 4A View Figure 4 ), consisting of single mid-dorsal stalked structure constituted by two pairs of similar-sized lobes; branchial lobes fused together for the most part of their length; a short additional anterior projection (‘‘fifth lobe’’) also present ( Figure 4A View Figure 4 ). Posterior region of superior lobes (i and ii) with pointed projection ( Figure 4A View Figure 4 ). Branchial lamellae provided with ciliated rows on both sides and tufts of cilia at dorsal edge ( Figure 2C–D View Figure 2 ). Lateral lappets on chaetigers 1 to 5 (segments 3 to 7), particularly developed in chaetigers 1 and 2 ( Figure 1B View Figure 1 , 2A View Figure 2 , 3A View Figure 3 , 4A View Figure 4 ); anterior margins separated from body wall. Rounded dorsal projections from chaetiger 1 to 5 ( Figure 2A View Figure 2 ). Ventral glandular bands absent.

Notopodia numbering 18 pairs (segments 3 to 20), compact, rectangular and of similar size except those of chaetiger 1 which are smaller ( Figure 3B View Figure 3 ). Neuropodia present from chaetiger 6 (segment 8) to pygidium. Thoracic neuropodia as broad sessile pinnules ( Figures 1C View Figure 1 , 2G View Figure 2 ); abdominal neuropodia as erect pinnules ( Figures 3G View Figure 3 , 4G View Figure 4 ). Notochaetae of first chaetiger shorter and less numerous than in subsequent notopodia. All notochaetae simple, broad-winged capillaries ( Figure 2E View Figure 2 ) with textured surfaces ( Figure 4C View Figure 4 ) and tubular internal structure ( Figure 2F View Figure 2 ). No accessory chaetae.

First thoracic neuropodium (chaetiger 6) with 10 gently bent, acute-tipped, geniculate acicular hooks ( Figures 3C View Figure 3 , 4B View Figure 4 ) with internal structure formed by fused hollow channels ( Figure 3D View Figure 3 ). Second and all subsequent thoracic neuropodia with about 45 (chaetiger 7) to about 80 (chaetiger 18) uncini; uncini of each torus arranged in several rows ( Figures 2G View Figure 2 , 4D View Figure 4 ); uncini as denticulate hooks with main fang large and surmounted by 4–6 big teeth and a crest of numerous denticles ( Figures 2H View Figure 2 , 4E View Figure 4 ); dental formula: MF:4–6: ‘. Abdominal neuropodia numbering 54; about 80 avicular uncini per torus with 5–6 teeth above main fang surmounted by 2– 4 teeth and an upper crest of a variable number of smaller teeth ( Figures 3H View Figure 3 , 4H View Figure 4 ); dental formula: MF:5–6:2–4: ‘. No abdominal notopodia. One abdominal constriction between chaetigers 17 and 18 ( Figures 1A View Figure 1 , 4F View Figure 4 ).

One large nephridial papilla attached to notopodium of chaetiger 1 (segment 3), with appearance of long, distally truncated cone. Two shallow and wider buttonholelike nephridial pores located on basal part of notopodia of chaetigers 4 and 5 (segments 6 and 7) ( Figure 2A View Figure 2 ). Small papillae arising dorsally to all thoracic ( Figures 3E–F View Figure 3 ) and abdominal ( Figures 3G View Figure 3 , 4G View Figure 4 ) chaetigers. Pygidium blunt, with funnel-like depression with crenulated edge.

Additional observations from type ( SMNH) and non-type material ( NHM)

The presence of short papillar projections on the outer side of the branchial lamellae reported by Solis-Weiss et al. (1991) in some Atlantic South American species and by Jouin-Toulmond and Hourdez (2006) in North Atlantic T. stroemii were not observed in this species. The damaged margin of one branchial lamella in SMNH 6625 ( Figure 2D View Figure 2 ) shows the internal structure of the marginal efferent blood vessel reported by Jouin-Toulmond and Hourdez (2006) for T. stroemii . Geniculate acicular hooks are clearly acute tipped and gently bent ( Figures 3C View Figure 3 , 4B View Figure 4 ). The rows of thoracic uncini vary between 1–2 in smaller animals ( Figure 4D View Figure 4 ) to 4–5 in larger ones ( Figure 2G View Figure 2 ). The uncinal patch shows the highest number of uncinal rows in the central area, showing fewer rows in the formative (dorsal) and degenerative (ventral) edges. Number of abdominal chaetigers varies between 42 in smaller specimens (about 1.6 cm length, SMNH 6634) and 54 in larger ones (7.6 cm, NHM 1930.10.8.2234). The abdominal constriction between abdominal chaetigers 17 and 18 was observed in all specimens; this character was not reported in any other species of Terebellides . As Monro (1930:199) pointed out, one specimen has 19 notopodia ( NHM 1930.10.8.2234), the neuropodia being a very small patch; this extra thoracic chaetiger is only present on the right side, the left having the usual abdominal nature.

The two trichobranchid specimens identified as T. longicaudatus by Hartman (1978) ( USNHM 47075-76) do not correspond to this species. Although these specimens are in poor condition and have lost the branchiae, they have large notochaetae in the first chaetiger and a small number of uncini in thoracic neuropodia which suggests that they cannot represent specimens of T. longicaudatus .

Ecological notes

Type material was collected in shallow muddy bottoms with stones at depths of between 75 and 310 m. Monro (1930) reported this species in similar sediments from 110–500 m.

Reported distribution

South Georgia ( Hessle 1917; Monro 1930). The only specimen reported by Monro (1930) out of South Georgia, from station 182 in the Schollaert Channel (Palmer Archipelago) ( NHM 1930.10.8.2166), corresponds to T. kerguelensis .

Terebellides antarcticus Hessle, 1917 View in CoL

Hessle 1917:140, plate I, figure 18, Textfigure 31; Hartman 1953, page 11.

Type material

Swedish Museum of Natural History, Stockholm. SMNH 6639 View Materials ( Antarctic , Graham region, 360 m depth, 64 ° 03 9 S; 56 ° 37 9 W, soft clay, SSPE st. 8; two specs.) GoogleMaps , SMNH 6640 View Materials ( SSPE, st. 8; two specs.) , SMNH 6641 View Materials ( Antarctic , Graham region, Admiralitäts

Sund, 5–9 m depth, 64 ° 20 9 S; 57 ° W, small stones and gravel, SSPE, st. 09; one spec. GoogleMaps ), SMNH 541 View Materials ( SSPE, st. 8; one spec.) .

Reported distribution

Graham’s Land, Antarctic Peninsula ( Hessle, 1917; Hartman, 1953). Remarks

Hessle (1917:139) characterizes this species by the absence of lateral lappets in segments 3 and 4 (chaetigers 1 and 2) and by the small number (10–20 per unciniger) and shape (5 teeth over the rostrum and 2–3 upper teeth) of thoracic uncini. Notochaetae of chaetiger 1 are of about the same length as the rest of the thoracic notochaetae, and prostomium, branchiae and distribution and shape of chaetae is similar to those of T. stroemii , T. minutus and T. longicaudatus . Syntypes SMNH 541 and 6639 are of large size (ca. 60 mm) and have 34 and 37 abdominal chaetigers, respectively; those numbers are smaller than those in specimens of T. longicaudatus of similar length (e.g. 54 abdominal neuropodia in holotype which is 55 mm in length). The SMNH 541 specimen has oocytes and chaetigers 1 to 3 have lateral lappets. The two specimens labelled as SMNH 6640 are anterior ends which represent those illustrated by Hessle to draw the uncini illustrated in the original description (cf. Hessle 1917, TextFigure 31:140 and pl. I, Figure 18) because the sides of those specimens seem to have been dissected. Only one specimen has branchiae which show cilia on lamellae arranged in a similar fashion as those of T. kerguelensis ( Parapar and Moreira 2008) .