Tromikosoma australe Koehler 1926

• Main Author: Anderson, Owen F.
• Format: Other/Unknown Material
• Language: unknown
• Published: 2016
• Subjects: Biodiversity; Taxonomy; Animalia; Echinodermata; Echinoidea; Echinothurioida; Echinothuriidae; Tromikosoma; Tromikosoma australe; Antarctic; Antarc*
• Online Access: https://zenodo.org/record/6055444; https://doi.org/10.5281/zenodo.6055444

Tromikosoma australe (Koehler 1926) ( Figures 10–13) Material examined. 10 specimens from 3 records (all NIWA). Northeast Tasman Sea: 1 specimen (160 mm TD), 34 ° 31.5´S, 166 ° 21´E, 2930 m, NIWA 45040; 8 specimens (180, 160, 98 (dry), 88, 82, 74, 61, 51 mm TD), 35 ° 43.7´S, 160 ° 16.2´E, 3480 m, NIWA 45092; 1 specimen (29 mm TD), 38 ° 37.3´S, 165 ° 36´E, 2417–2421 m, NIWA 45121. Unless stated all stored in 80 % ethanol. Size range. The 10 specimens range in size from 29 mm to 180 mm TD. Occurrence. All three records are from deep water in the Tasman Sea, near the Lord Howe Rise (Figure 11). The potential depth range for the species is 2417–3480 m. Remarks. These specimens represent the first records of this species since it was discovered off South Australia by the Australasian Antarctic Expedition of 1911 – 14 and subsequently described by Koehler (1926). Recent examination of the holotype in the Australian Museum revealed the (dry) specimen to be in very poor condition and the test could not be examined in any detail without causing further damage. However the Aristotle’s lantern had disarticulated and the components could be examined. Comparison of the hemipyramids and rotulae with those of the Tasman Sea specimens showed a perfect match. Although the Aristotle’s lantern is not typically used for distinguishing species, personal observation of Araeosoma species has revealed considerable variation in that genus, and features of the lantern should be assessed for their taxonomic value. The pedicellariae figured by Koehler also matched well to the new specimens: two forms of tridentate pedicellariae are present (Figure 12); a large form of a design typical for the genus (see Mortensen 1935, Mironov 1971, Campbell 1993) with an elongated, open blade edged with very fine serrations, about 0.7–1.6 mm long; and a small form (0.4–0.5 mm long) not much longer than wide with a rounded, spoon-shaped blade. As Koehler stated, although it was not well shown by his figures, the narrowing of the valve between the base and ...