Caulleriella cordiformia, Magalhães, Wagner F. & Bailey-Brock, Julie H., 2013

Magalhães, Wagner F. & Bailey-Brock, Julie H., 2013, Bitentaculate Cirratulidae (Annelida: Polychaeta) from the northwestern Pacific Islands with description of nine new species, Zootaxa 3630 (1), pp. 80-116 : 92-94

Caulleriella cordiformia sp. nov.

Figures 8 A–E, 9 A–F

Material examined. Holotype: Mamala Bay, Sand Island outfall, south shore of Oahu Island, Hawaii, Sta. E2R2, 21°16ʹ43.4ʺ N, 157°54ʹ38.8ʺ W, 102.4 m, Aug. 2008 (USNM 1195155). Paratypes: same locality and date as holotype, Sta. E2R3, 21°16ʹ43.4ʺ N, 157°54ʹ38.8ʺ W, 101.5 m (6 specimens on stub, USNM 1195156; 1, BPBM R3645).

Description. Holotype 3.0 mm long, 0.2 mm wide with 46 chaetigers. Paratypes 1.5–4.0 mm long, 0.1–0.2 wide for 33–52 chaetigers. Body robust, short, wider in mid-body segments than on anterior and posterior ones. In cross section, anterior end rounded dorsally, flattened ventrally; middle and posterior segments with shallow ventral groove. Specimens in alcohol white to yellow in color. Pygidium bilobed, heart-shaped ( Figs. 8 C, 9F).

Prostomium triangular, elongate, as long as two anterior chaetigers, without eyes and with a pair of posterolateral nuchal organs as vertical slits ( Figs 8 A, B, 9A, B). Nuchal organs oval patches (10–12 µm) situated in a shallow pit composed of numerous short cilia. Peristomium longer than prostomium (as long as three anterior chaetigers) with three annulations ( Fig. 9 B). First and second peristomial annulation sub-equal dorsally; second peristomial annulation shorter, and expanding dorsally as a weak crest over the third peristomial annulation ( Fig. 9 B). Third peristomial annulation difficult to discern from chaetiger 1, partially fused. Dorsal tentacles situated on anterior margin of third peristomial annulations, followed by a pair of branchiae ( Fig. 9 A, B). Branchiae present throughout, one pair per segment, arising near to notopodial ridge.

Parapodia laterally positioned with notopodia and neuropodia widely separated. In posterior end, the distance between noto- and neuropodia is reduced. Notochaetae of anterior chaetigers simple capillaries arranged in two rows of four capillaries ( Fig. 9 C). Bidentate notohooks with main fang slightly curved, long apical tooth, and without hood alternating with companion capillaries from chaetigers 16–20, up to five hooks ( Figs 8 D, 9D). On posterior notopodia, four long bidentate hooks (three times longer than anterior ones) alternate with four capillary chaetae. Neurohooks similar to notopodial hooks, present from chaetiger 6–10, numbering 4–5 per fascicle. Posterior neurohooks numbering 4–5 hooks, as short as anterior ones, alternating with 4–5 slender bidentate hooks, as short as the more robust hooks, with same-sized teeth ( Figs 8 E, 9E, F).

MGSP. Prostomium stained intensely leaving anterior tip unstained; lateral and ventral side of peristomial annulations stained forming lateral bands; the rest of the body including tentacles and branchiae stained homogeneously a light green ( Fig. 8 F).

Remarks. Caulleriella cordiformia sp. nov., is a distinctive species in the genus because of some unique features such as third peristomial annulation partially fused with chaetiger 1, origin of notohooks (chaetigers 16–20) and neurohooks (chaetigers 6–10), presence of very long posterior notopodial hooks, distinct slender, bidentate hooks with same-sized teeth in posterior neuropodia, and a bilobed and heart-shaped pygidium. It is readily distinguished from the other Caulleriella species present in Hawaiian waters, Caulleriella bioculata , by the shape of the pygidium, which is bilobed and heart-shaped in C. cordiformia and two slender cirri in C. bioculata and by the earlier origin of neurohooks (chaetiger 4) in the latter.

Etymology. The epithet “ cordiformia ” comes from the Latin word which means “heart-shaped”, referring to the shape of the pygidium of this new species.

Biology/Ecology. Caulleriella cordiformia sp. nov., was collected in soft bottom sediments surrounding the Sand Island Wastewater Outfall at 102 m in depth.

Distribution. Mamala Bay, south coast of Oahu Island, Hawaii, USA.

Figures

FIGURE 8. Caulleriella cordiformia sp. nov. A, anterior end, dorsal view; B, anterior end, dorso-lateral view; C, posterior end with pygidium; D, bidentate hooks from anterior abdominal chaetigers; E, bidentate hooks of two types from posterior end segments; F, MGSP of a complete specimen.

FIGURE 9. SEM of Caulleriella cordiformia sp. nov. A, anterior end, dorsal view; B, anterior end, lateral view; C, thoracic capillary chaetae; D, chaetigers 5 - 7 showing commencement of neuropodial bidentate hooks on chaetiger 6; E, posterior end bidentate hooks; F, posterior end with pygidium.