Caulleriella parvinasa, Blake & Dean, 2019

Blake, James A. & Dean, Harlan K., 2019, New Species of Cirratulidae (Annelida, Polychaeta) from the Caribbean Sea, Zootaxa 4671 (3), pp. 301-338 : 312-314

Caulleriella parvinasa new species

Figure 7

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Material examined. Caribbean Sea, Carib 1, R/V Alpha Helix , Honduras, Cayo Aspero, Isla de Utila, Sta. MS-48-500, 16°04.8ʹN, 87°00.2ʹW, 14 July 1977, intertidal, meiobenthic sled, depth 1–10 cm in algae and sand and along a sandy beach interface on leeward side, holotype ( USNM 1557508 ) .

Description. A small species, holotype complete, 3.7 mm long and 0.5 mm wide across thorax for 56 setigers. Anterior or thoracic region wide with crowded segments and notopodial tori elevated over dorsum for 35 setigers. Body rectangular in cross section with thickened notopodial ridge at superior corners and low neuropodial ridge at inferior corners. Neuropodia extending below venter in thoracic region forming a wide, flat groove on each segment for 35 thoracic setigers. Abdominal region a depressed oval in cross-section, parapodial lobes forming low ridges. Color in alcohol pale tan.

Pre-setiger region triangular, widest posteriorly, about as wide as long at border with setiger 1 ( Fig. 7A ). Prostomium short, conical, pointed apically, with large, diffusely pigmented nuchal organs located dorsolaterally, but also visible dorsally ( Fig. 7 A–B). Peristomium large, with three annular rings, second ring longest, widening posteriorly ( Fig. 7 A–B), third ring extending over setiger 1 and onto dorsum of setiger 2; narrow mid-dorsal crest extending along most of peristomium including posterior extension over setigers 1–2. Dorsal tentacles visible as wide flattened scars at posterior margin of peristomium anterior to setiger 1 ( Fig. 7B ). First pair of branchiae on setiger 1, dorsal to notosetae; subsequent branchiae similarly positioned relative to notosetae; branchiae long and thin.

Notosetae include 2–5 capillaries for first 27 setigers, bidentate hooks, accompanied by capillaries, from setiger 28, subsequent setigers with 2–5 hooks accompanied by 1–2 capillaries or, occasionally, capillaries lacking. Setiger 1 with six bidentate neuropodial hooks and single accompanying capillary; hooks increasing to 4–8 in subsequent setigers, sometimes accompanied with a capillary. Hooks with small apical tooth above main fang, crest or hood absent ( Fig 7D ).

Last three body segments asetigerous, pygidium an elongate rounded cone with groove separating two lobes, anus dorsal ( Fig. 7D ).

Methyl Green stain. No pattern; the body stains a uniform dark blue with exception of the unstained prostomium and pygidium.

Remarks. Species with a similar first occurrence of the notopodial and neuropodial hooks and the emergence of the first branchiae on setiger 1 include Caulleriella cristata from central California, C. dulcensis Dean & Blake, 2007 from Costa Rica, and C. lajolla Blake, 1996 from southern California. The first occurrence of the neuropodial hooks is setiger 1 in all species; the first occurrence of notopodial hooks is setiger 28 in C. parvinasa n. sp., setiger 14–30 in C. cristata , setiger 23 in C. dulcensis , and setiger 25–26 in C. lajolla . However, all of the previously described species have dorsal tentacles emerging from above setiger 1 or 2 rather than the posterior margin of the peristomium as in C. parvinasa n. sp. Additionally C. dulcensis and C. lajolla lack the dorsal peristomial crest that is present in C. parvinasa n. sp. and C. cristata lacks accessory capillaries in all neuropodia while they are present in some anterior setigers in C. parvinasa n. sp.

Etymology. This species name is from the Latin parvus for little or less and nasus for nose, in reference to the small, conical prostomium.

Distribution. Honduras, known only intertidally from a sandy beach in Cayo Aspero, Isla de Utila; occurs in shallow (1–10 cm deep in the sediment) sand and algae.

Figures

FIGURE 7. Caulleriella parvinasa n. sp. Holotype (USNM 1557508): A, anterior end, dorsal view; B. anterior end, ventral view; C, posterior end, dorsal view; D, neuropodial acicular spine from posterior setiger.