Colossendeis tasmanica, Staples, 2007

Staples, David A., 2007, A new species of Colossendeis (Pycnogonida: Colossendeidae) together with records from Australian and New Zealand waters, Memoirs of Museum Victoria 64, pp. 79-94 : 88-90

Colossendeis tasmanica sp. nov.

Figures 3A–H , Table 1

Material examined. Holotype: Tasmania, E of Furneaux Group from 39°48.27'S, 149°06.02'E 1923 m, to 39°47.06'S, 149°05.19'E, 1962 m, McKenna Market trawl. RV Southern Surveyor , CSIRO, 29 Apr 2000 (SS01/00 stn 260), NMV J55741 .

Paratypes: Details as for holotype, NMV J55742 (4 specimens) .

Other material. New South Wales. 67 km ENE of Nowra , from 34°41.97'S, 151°22.44'E, 1896 m, to 34°42.14'S, 151°21.72'E, 1642 m, 3.5 m beam trawl, RV Franklin, G.C.B. Poore et al., 22 Oct 1988 (stn Slope 59), NMV J54503 (3 specimens) . Off Nowra , from 34°58.40'S, 151°23.20'E, bottom 1750 m, to 34°56.40'S, 151°29.10'E, bottom 1650 m to 1750 m, trawl , 5 m Otter, RV Franklin, M.F. Gomon et al., 16 Jul 1986 (stn Slope 15), NMV J40746 (2 specimen) . 100 km ENE Nowra , from 34°34.43'S, 151°40.82'E, 2800 m, to 34°34.45'S, 151°39.89'E, 2700 m, trawl, 3.5 beam, RV Franklin, G.C.B. Poore et al., 23 Oct 1988 (stn Slope 60), NMV J40742 (2 specimens) . Tasmania. E of Furneaux Group from 39°48.27'S, 149°06.02'E 1923 m, to 39°47.06'S, 149°05.19'E, 1962 m, McKenna Market trawl, RV Southern Surveyor , CSIRO, 29 Apr 2000 (SS01/00 stn 260), NMV J48897 (30 specimens) . E of Furneaux Group from 39°48.27'S, 149°06.02'E 1923 m, to 39°47.06'S, 149°05.19'E, 1962m, McKenna Market trawl, RV Southern Surveyor , CSIRO, 29 Apr 2000 (SS01/00 stn 260), MNZ PY.56 (2 specimens) . 41 km NE of Cape Tourville, Freycinet Peninsula , from 41°54.54'S, 148°45.15'E, 1273 m, to 41°42.60'S, 148°42.60'E, 1190 m, trawl, 3.5 beam, RV Franklin, G.C.B. Poore et al., 30 Oct 1988, (stn Slope 83), NMV J40743 (1 specimen) . victoria. 85 km E of Point Hicks from 38°31.41'S, 149°21.10'E, 1986 m, to 38°30.58'S, 149°21.50'E 1360 m, 3.5 m beam trawl, RV Franklin, G.C.B. Poore et al., 26 Oct 1988, (stn Slope 72) NMV J40744 , (18 specimens) . 38°30.66'S, 149°22.99'E to 38°30.89'S, 149°21.63'E, 1859 m, Epibenthic sled, RV Southern Surveyor , CSIRO, 19 Apr 2000, (SS01/00 stn 172), NMV J48899 (4 specimens) .

Diagnosis. A large species. Colossendeis colossea -like. Lateral processes clearly separated. Proboscis bottle-shaped, 1.7–2.0 times length of trunk, straight, median swelling preceded by narrower basal part and tapering distally to terminate in a rounded oral surface. Abdomen articulated, maximum width in distal one-third, length 19–29 % of trunk. Palp segment 3 longest, segment 10, 6.3–7.4 times as long as median width. Oviger 10-segmented, terminal claw strongly curved, distinctly articulated with segment 10, segment 10 not tapered distally.

Description of holotype. (Range of variability in brackets). Leg span up to about 550 mm (400–550 mm). 2nd and 3rd lateral processes separated by about one-sixth of basal width (one-sixth to greater than half). Cephalon directed downwards slightly. Ocular tubercle bluntly conical with apical papilla (bluntly conical or broad in anterior view, mid-dorsal papilla variably developed), 2 well-developed eyes, unpigmented in preserved specimen, lateral sensory organs prominent; post-ocular mound low. Abdomen originating from lateral surface between 4th pair of legs, length 21% (19–29%) of trunk, clavate, anus on dorsodistal surface. Proboscis 2.0 (1.7–2.0) times length of trunk and 6.4 (6.1–6.8) times as long as maximum width (subadults about 7.2 times), straight, median swelling preceded by narrower basal part and tapering distally to terminate in a rounded oral surface, width at tip 1.3 (1.2–1.4) times basal diameter. Oviger 10-segmented, terminal oviger claw hooked and distinctly articulated with segment 10; proximal and distal widths of segment 10 about equal, length 3.4 (2.5–3.5) times distal width (measured from outer margin to base of spines); strigilis strong, carried somewhat horizontally with claw resting against outer, or lower, side of segment 10; spine fields on segments 7–10 dense, trailing edge spines longer, laid-back, individual spines each with fine marginal serrations, particularly evident in subadults (fig. 3H), scattered, short, simple, spines on longer segments; segment 6 marginally longer than segment 4 (equal to 1.1 times), single gland opening on interior surface of segment 4 at about 75% of length. Palp segment 3, 1.2 times longer than segment 5 (1.0–1.2); segment 7, 2.4 times segment 6 (2.2–2.5); segment 10 narrowing markedly towards tip, slightly irregular distally with a slight to marked constriction, length 7.3 (6.3–7.4) times median width, with 3 to 4, forward-facing spines at the tip (fig. 3K) and 2–4 strong spines on inner and ventral margins, smaller spines all over; spines most abundant on segments 7 and 8; single gland openings on outside surface of segment 5. Leg length 12.2 (9.3–12.2) times trunk, longer segments with scattered, short spines, femur curved, 25–33 times as long as distal width, equal to, or a little longer than tibia 1; tibia 1 about 25% longer than tibia 2, tarsus 1.7–2.8 times propodus; terminal claw 40–72% length of propodus; coxal pellicula are present on the dorsal surface of coxa 2 of all legs in adult forms, absent or not evident in subadults; genital pores on the proximal surface of a low distoventral transverse ridge on legs 3 and 4.

Measurements of holotype (in mm). Length trunk (frontal margin cephalic segment to tip 4th lateral process), 21.5; width across 2nd lateral processes, 11.0; length proboscis (lateral) 42.0; greatest width proboscis, 6.6; length abdomen, 4.5. Third leg: coxa 1, 3.1; coxa 2, 5.3; coxa 3, 5.3; femur, 86.0; tibia 1, 86.0; tibia 2, 68.0; tarsus, 5.5; propodus, 3.5; claw, 1.5. Measurement of palp segments (in mm). Seg. 1, 1.3; seg. 2, 0.8; seg. 3, 13.1; seg. 4, 2.1; seg. 5, 16.7; seg. 6, 4.2; seg. 7, 10.1; seg. 8, 4.6; seg. 9, 3.9; seg. 10, 4.1.

Etymology. Referring to the collection locality, the Tasman Sea.

Distribution. East coast of Australia; off the coast of Portugal, 1190–2800 m depth.

Remarks. This species shares much in common with C. colossea but constant and conspicuous differences in the articulation of the oviger claw, the less tapered oviger segment 10, the proportions of the abdomen and the longer, more slender palp segment 10, distinguish the species ( Table 1).

Size differences of genital pores were noted between specimens. The smaller pores were about half the size of the larger, but based on this difference alone, specimens could not be assigned to sex with confidence. To some extent, the size of these pores is proportionate to the size of the specimen and in the apparent absence of other dimorphism, sex is uncertain. The abdomen shows slight variability; in some cases more narrowed distally than in others. Leg spans of subadults were in the range of 290–350 mm. The oviger claw is straight to slightly curved and palp segment 10 is much shorter that in adults, the length ranging from about 4 times median width. Articulation of the oviger claw with segment 10 is constant, but the shape of the claw and the proportions of palp segment 10 are unquestionably correlated with maturity. To enable comparison with C. colossea , the length of oviger segment 10 is measured from the proximal margin of the segment to the distal edge of the spine field rather than to the point of articulation with the claw. The width of the segment is measured from the outer margin of the segment to the base of the spines. The particularly fine serrations of the oviger spines in subadults is perhaps indicative of a lack of wear and the spines are very thin, so much so, that the tip of several spines were folded over (fig. 3H). Although not a constant character, the first lateral processes were less inclined and directed more forward than in C. colossea .

Colossendeis tasmanica is found sympatric with C. colossea in the Tasman Sea although of the 75 specimens documented in this report, the two species were never recorded together from the same collection site. Regional records of C. tasmanica are confined to the eastern coastline, whereas C. colossea is more widely spread around the Australian continent and elsewhere. Nogueira, (1967) recorded and illustrated what appears to be a juvenile C. tasmanica from a similar depth to the Tasman Sea specimens off the coast of Portugal, confirming the probability that records of C. tasmanica lie unrecognised amongst collections of C. colossea . Regional records of C. tasmanacia are from a greater depth than those for C. colossea . This species also shares a resemblance to C. curcurbita ( Cole, 1909) , previously recorded in the region from New Zealand and south of Australia. Colossendeis cucurbita can be readily distinguished from C. tasmanica by the shape of the terminal oviger claw and the proportions of the palp segments. Colossendeis cucurbita is a member of the ‘ macerrima complex’ a group characterized by having palp segment 3 much shorter than 5 and in which the three distal most segments are equal to, or less than, segment 7. Based on Cole’s illustration of the holotype (pl. 3, fig. 7), the proboscis is more upturned and wider distally than C. tasmanica .

Encapsulated juvenile gastropods were attached to the legs of several specimens of C. tasmanica and in one case, to the trunk and proximal palp segments. Most capsules contain a single gastropod and many had been vacated. This apparent phoretic association with the genus Colossendeis is common and although not evidenced in this material, may extend to being symbiotic or ectoparasitic ( Sirenko, 2000; Lehmann et al. 2006). Two deep-water species of stalked barnacle were recorded primarily on the dorsal surfaces of the trunks and legs of several specimens. Glyptelasma carinatum ( Hoek, 1883) is a cosmopolitan barnacle species previously recorded from the Challenger Plateau, Tasman Sea and the other species, tentatively placed in Catherinum sp. cf sinuatum ( Pilsbry, 1907), is a deep-water Atlantic species (J. Buckeridge pers. com.).

Figures

Figure 3. Colossendeis tasmanica (J48897): A, B, dorsal and lateral views of trunk; C, ocular tubercle; D, tarsus and propodus; E, oviger; F, oviger segment 10; G, (J40744), juvenile oviger segment 10; H, oviger spines; I, palp; J, palp segments 8–10; K, tip, palp segment 10.