Trypanobia cryptica, Aguado, M. Teresa, Murray, Anna & Hutchings, Pat, 2015

Aguado, M. Teresa, Murray, Anna & Hutchings, Pat, 2015, Syllidae (Annelida: Phyllodocida) from Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 35-60 : 54

Trypanobia cryptica n. sp.

( Figs 11 , 12 , 13 )

Material examined. Holotype: AM W.44443, MI QLD 2368, (part on SEM pins, anterior end fixed in 100% ethanol).

GenBank COI accession number: KR534503

Description. Holotype in three fragments; anterior end 1.5 mm wide, 0.4 mm long, with 24 chaetigers; midbody piece 0.5 mm long, with 33 chaetigers; posterior end 1 cm long, with 54 chaetigers, plus one developing stolon of 14 additional chaetigers. Live specimen strongly pigmented with bright red ( Figs 11 A–B); preserved specimen whitish with reddish glandular material within articles of posterior dorsal cirri. Body strongly dorsoventrally flattened, ribbon-like, with series of longitudinal crests on each segment. Prostomium rounded, bilobed, with four circular red eyes in rectangular arrangement ( Fig. 12 A). Palps short, ventrally directed, completely separate. Antennae inserted on anterior margin of prostomium; median antenna inserted between anterior pair of eyes, with approximately 10 articles, lateral antennae inserted on anterior margin of prostomium, with approximately 15 articles. Peristomium dorsally reduced; dorsal tentacular cirri longer than antennae, with approximately 20 articles; ventral tentacular cirri about half the length of dorsal ones. Tentacular and dorsal cirri with well developed cirrophores; dorsal cirri relatively short and thick, with approximately 15–20 articles and granular material inside. Posterior dorsal cirri strongly alternating in length and width, longer ones directed dorsally with 17 articles, and shorter ones, laterally directed, with 11 articles. Parapodia with distinct rounded dorsal lobes ( Fig. 11 H). Ventral cirri conical, not exceeding the length of parapodia. Chaetae similar throughout body, thick, subdistally slightly enlarged, distally unidentate, with basal spur relatively short ( Figs 11 C–G, 12B, 13A–F). Anterior and midbody parapodia with 4 simple chaetae, two of which are shorter and more dorsally located ( Figs 11 C, 13C, E). Chaetae reduced in number to 2–3 in posterior parapodia ( Fig. 13 F). Anterior parapodia with 3–4 aciculae, straight and distally pointed, occasionally protruding from parapodia ( Fig. 11 I), aciculae decreasing in number to 2 in posterior chaetigers. Pharynx relatively slender, through approximately 10 segments, with a distal trepan surrounded by a crown of soft papillae. Proventricle similar in width to pharynx, slender, through approximately 15 segments.

Stolon. Developing female stolon of 14 chaetigers, full of circular oocytes, still attached to parental body. One pair of red eyes ventrally visible, another pair possibly developing, one pair of small anterolateral appendages developing. Four simple chaetae per segment, same as those of parental body, notochaetae absent.

Remarks. Trypanobia cryptica n. sp. possesses strong bright red colouration perfectly matching the colour of the sponge with which it was found in association. The most similar species is T. asterobia Okada, 1933 ; however this species is described with three kinds of chaetae: superiormost are distally falcate ones with a subterminal spur, median chaetae are falcate with a subterminal spur and minute serrations along the cutting margin, and inferior chaetae are distally bent and simple ( Okada 1933; Imajima 1966b). Trypanobia cryptica n. sp. has only one kind of simple chaetae with a short basal spur that becomes more evident in posterior chaetigers. Additionally, T. asterobia was found in association with an asteroid, Luidia quinaria von Martens, 1865, and live specimens lacked a distinct colour pattern ( Okada 1933). We also provide its COI sequence, essential for future identification when other specimens are eventually found.

Etymology. The specific name makes reference to the cryptic body colour pattern.

Habitat. On red sponges, from 6–9 m depth.

Distribution. Australia (Queensland).

Figures

FIGURE 11. Trypanobia cryptica n. sp. AM W. 44443. A. anterior end, dorsal view; B. Whole specimen, ventrolateral view, arrow pointing attached stolon; C – E Mid-body simple chaetae; F – G. Posterior chaetae; H. dorsal parapodial lobe, midbody chaetiger; I. Mid-body parapodium, aciculae protruding. Scale bars: C = 100 µm; D = 20 µm; E – H = 50 µm; I = 20 µm.

FIGURE 12. Trypanobia cryptica n. sp. AM W. 44443. A. anterior end, dorsal view; B. Mid-body chaetae. Scale bars: A = 0.1 mm; B = 20 µm.

FIGURE 13. SEM. Trypanobia cryptica n. sp. AM W. 44443. A. Mid-body chaetigers, dorsal view; B. Mid-body chaeta; C. Mid-body chaetigers, dorsal view; D. Mid-body chaetae; E. Mid-body chaetigers, ventral view; F. Posterior chaetigers, ventral view.