Caulleriella cucula, Dean, Harlan K. & Blake, James A., 2007

Dean, Harlan K. & Blake, James A., 2007, Chaetozone and Caulleriella (Polychaeta: Cirratulidae) from the Pacific Coast of Costa Rica, with description of eight new species, Zootaxa 1451, pp. 41-68 : 52-54

Caulleriella cucula sp. nov.

Figures 6 A–D, 7C.

Caulleriella alata: Maurer et al. 1988:46 ; Dean 1996a:71; Not Southern, 1914.

Caulleriella bioculata: Vargas et al. 1985:335 ; Maurer et al. 1988:46; Not Keferstein, 1862:121 -122. Caulleriella magnaoculata: Dean 2004:138 ; Not Hartmann– Schröder 1962:139 -140, Figures 107-109. Caulleriella sp.: Vargas et. al. 1985:335.

Material Examined. Costa Rica, Golfo de Nicoya. Holotype: Sta. 29, 9°54'55"N, 84°45'15"W, 18 m, muddy sand, 11 Jul 1980, ( MCZ 67147). Paratypes: Sta. 2, 9°55'28"N, 84°52'05"W, 18 m, muddy sand, 10 Jul 1980, (1 USNM 80123); Sta. 29, 9°54'55"N, 84°45'15"W, 18 m, muddy sand, 11 Jul 1980, (1 MCZ 67148).

Comparative material examined. Costa Rica, Golfo de Nicoya. Sta. 1, 9°57'30"N, 84°53'00"W, 46 m, mud, 10 Jul 1980 (1 HKD). Sta. 29, 9°54'55"N, 84°45'15"W, 18 m, muddy sand, 11 Jul 1980, (2 USNM 80124, 80125), (2 HKD); 1 Oct 1980 (14 HKD); 27 Jan 1981, (16 HKD); 4 Apr 1981, (19 HKD); 7 Jun 1981 (19 HKD). Sta. 37, 9°57'38"N, 84°48'20"W, 14 m, muddy sand, 10 Jul 1980, (1 USNM 80126). Sta. 48, 10°07'25"N, 84°07'40"W, 9 m, mud, 10 Jul 1980, (1 USNM 80158).

Small species, holotype 6.3 mm long, 0.4 mm wide for 128 setigers; complete specimens ranging from 4.4 mm long, 0.2 mm wide for 92 setigers to 10.8 mm long, 0.4 mm wide for 131 setigers (n = 8). Body thin, anterior setigers circular in cross section, middle and posterior setigers weakly flattened dorsoventrally; anterior setigers crowded relative to middle and posterior setigers; notopodial and neuropodial lobes low-lying, swollen lobes; notopodial and neuropodial setal bundles widely separated. Pygidium simple conical lobe with ventral anus ( Fig. 6 C). Body pale tan in alcohol.

Prostomium long, conical; with elongate nuchal organs opening posteriorly beneath overlying peristomial crest, leading to large, L-shaped, darkly pigmented spaces nearly abutting each other medially ( Fig. 6 A B). Peristomium large, with three annulations extending as wide crest over dorsum and lateral surfaces of posterior prostomium; two posterior annulations with distinct dorsal crest, weakly visible dorsally; first annulation approximately twice as long as second and third annulations; second and third annulation subequal ( Figs. 6 A B; 7C). Dorsal tentacles wide, flattened, arising at posterior border of third annulation; first pair of branchiae on setiger 1, arising dorsal to notosetal bundle; subsequent branchiae also dorsal to notosetal bundle at dorsal edge of notopodial lobe.

Notosetae of setigers 4–6 laterally pilose capillaries in anterior and middle setigers; bidentate hooks first appearing as single hook in setiger 92 in holotype, and from setiger 43–88 in paratypes, notopodial hooks increasing to three hooks accompanied by 2–3 thin, smooth capillaries in subsequent setigers ( Fig. 6 D). Neuropodial hooks weakly bidentate, present from setiger 1, beginning as single hook accompanied by 3–4 short, laterally pilose capillary setae; increasing to three hooks thereafter accompanied by 1–2 fine, short, capillary setae ( Figs. 6 D, 7D).

Methyl green staining pattern. Body uniformly green; prostomium unstained; peristomial crest and midventral band, extending length of body, weakly stained.

Habitat. Known from mud and muddy sand from subtidal sites in the Golfo de Nicoya at 9– 46 m.

Remarks. In two of the specimens some notopodial and neuropodial hooks appeared unidentate using light microscopy; scanning electron microscopy, however, reveals the sub-apical tooth was often greatly reduced yet still present in most of these hooks ( Fig. 7 D). While all hooks within a setal bundle usually exhibited similar development of the subapical teeth, an adjacent setiger could differ greatly. It is also quite likely that these weakly developed subapical teeth are worn, giving the appearance of a unidentate spine.

Caulleriella cucula sp. nov. shares the presence of large, dark nuchal organs with both Caulleriella apicula Blake, 1996 and Caulleriella magnaoculata Hartmann-Schröder, 1962 . In C. cucula sp. nov. these nuchal organs open to the exterior under the dorsal “hood” of the first peristomial annulation at the lateral surface of the prostomium ( Fig. 6 A). The nuchal organs enlarge as they extend posteriorly and flex medially, almost meeting each other at the midline. Brown coloration occurs in these enlarged interior spaces, giving the appearance of eyespots.

Caulleriella cucula sp. nov. is also similar to C. apicula in the first occurrence of the hooks in the notopodia and neuropodia but differs in having capillary neurosetae in all but the pre-pygidial setigers. Additionally, C. cucula sp. nov. has only 3 or 4 neuropodial hooks per ramus whereas C. apicula is reported to have up to 9–12 hooks in posterior neuropodia. C. magnaoculata and C. cucula sp. nov. have capillary setae in all neuropodia; however, in C. magnaoculata the first occurrence of neuropodial hooks is from setiger 10–12 instead of setiger 1. Further, the pygidium of C. magnaoculata , which is reported to turn upwards, is unlike the simple, conical pygidial lobe of C. cucula sp. nov.

Etymology. The specific name is taken from the latin cuculus, meaning cowl or hood and refers to the anterior, cowl-like projection of the peristomium over the prostomium.

Figures

FIGURE 6. Caulleriella cucula sp. nov. A. Lateral view, anterior end B. Dorsal view anterior end C. Pygidial region, left lateral view D. Posterior setiger, anterior view. Scale bars: A, B = 0.1 mm, C = 0.05 mm, D = 0.05 mm. a = annulations, no = nuchal organ.

FIGURE 7. Chaetozone nicoyana sp. nov. A. anterior end, lateral view B. posterior neuropodial setal bundle, anterior view. Caulleriella cucula sp. nov. C. anterior end, lateral view. D. neuropodial setal bundle, anterior view. Caulleriella dulcei sp. nov. E. anterior end, dorsal view. Caulleriella minuta sp. nov. F. anterior end, lateral view. no = nuchal organ, s = subacicular tooth.