Chaetozone and Caulleriella (Polychaeta: Cirratulidae) from the Pacific Coast of Costa Rica, with description of eight new species Author Dean, Harlan K. Author Blake, James A. text Zootaxa 2007 1451 41 68 journal article 10.5281/zenodo.176265 e5b7f616-8528-4813-93cd-819753d16855 1175-5326 176265 Chaetozone nicoyana sp. nov. Figure 5 A–E, 7 A B.

Chaetozone sp. B: Dean 1996a:72.
Chaetozone sp. D: Dean 2004:139.
Chaetozone setosa : Dean 1996a:72 ;	Not Malmgren,	1867:96,	pl.	14,	Figure	84.

Material Examined. Costa Rica , Gulf of Nicoya. Holtype: Sta. 29, 9°54'55"N , 84°45'15"W , 18 m , muddy sand, ( MCZ 67145). Paratypes : Sta. 29, 9°54'55"N , 84°45'15"W , 18 m , muddy sand, (10 USNM 80141); Sta. 32, 9°53'47"N , 84°49'35"W , 24 m , mud and sand, 11 Jul 1981 , (1 MCZ 67146; 2 UCRMZ 129). Comparative material examined . Costa Rica , Gulf of Nicoya. Sta. 3, 9°52'00"N , 84°48'10"W , 33 m , sandy mud, 10 Jul 1980 (1 USNM 80130). Sta. 4, 9°53'40"N , 84°46'10"W , 40 m , mud, 10 Jul 1980 (5 HKD). Sta. 12, 9°46'15"N , 84°41'50"W , 44 m , mud, 10 Jul 1980 (2 USNM 80131, 80132). Sta. 13, 9°52'30"N , 84°43'50"W , 26 m , 10 Jul 1980 (4 USNM 80133). Sta. 14, 9°57'05"N , 84°45'30"W , 9 m , sandy mud, 10 Jul 1980 (5 USNM 80134). Sta. 15, 9°57'40"N , 84°47'00"W , 15 m , sandy mud, 10 Jul 1980 (1 HKD). Sta. 22, 9°48'25"N , 84°52'40"W , 22 m , muddy sand, 11 Jul 1980 (2 USNM 80120, 80135). Sta. 23, 9°48'35"N , 84°43'50"W , 35 m , mud, 10 Jul 1980 (2 USNM 80136). Sta. 24, 9°49'25"N , 84°41'20"W , 11 m , sand, 1 Oct 1980 (7 HKD, as sp. B of Dean 1996a and sp. D of Dean 2004 ), 27 Jan 1981 (2 HKD), 4 Apr 1981 (5 HKD), 7 Jun 1981 (19 HKD), 4 Aug 1981 (16 HKD). Sta. 26, 9°51'50"N , 84°53'20"W , 17 m , muddy sand, 11 Jul 1980 (1 USNM 80137). Sta. 27, 9°51'57"N , 84°50'50"W , 12 m , muddy sand, 11 Jul 1980 (2 USNM 80138). Sta. 28, 9°52'16"N , 84°45'30"W , 26 m , mud, 11 Jul 1980 (1 HKD), 1 Oct 1980 (4 HKD), 4 Apr 1981 (5 HKD), 7 Jun 1981 (7 HKD), 4 Aug 1981 (6 HKD). Sta. 29, 9°54'55"N , 84°45'15"W , 18 m , muddy sand, 11 Jul 1980 (1 USNM 80139), 27 Jan 1981 (4 HKD), 4 Aug 1981 (54 HKD). Sta. 30, 9°54'40"N , 84°45'50"W , 18 m , muddy sand, 11 Jul 1980 (1 USNM 80140), 1 Oct 1980 (6 HKD), 27 Jan 1981 (11 HKD), 4 Apr 1981 (8 HKD), 4 Aug 1981 (15 HKD). Sta. 33, 9°53'40"N , 84°53'20"W , 11 m , mud, 11 Jul 1980 (2 HKD). Sta. 36, 9°55'32"N , 84°45'20"W , 18 m , sandy mud, 10 Jul 1980 (1 HKD). Sta. 44, 9°59'17"N , 84°54'25"W , 24 m , muddy sand, 10 Jul 1980 (1 USNM 80144). An elongate, medium-size species with wide anterior region of approximately 10 short setigers, middle and posterior region slightly moniliform, with setigers as long as, or longer than wide; podial lobes forming partial cinctures. Holotype 7.45 mm long and 0.3 mm wide for 50 setigers; complete paratypes 4.9 mm long and 0.2 mm wide for 50 setigers and 4.1 mm long and 0.15 mm wide for 47 setigers ( USNM 80141). Pygidium short cone with laterally expanded flap extending ventrally to, and beyond, anal opening ( Fig. 5 C). Color in alcohol uniformly light tan. Prostomium narrow, tapering with pair of oval, lateral nuchal organs at posterior border ( Figs. 5 A B; 7A). Peristomium slightly overlapping rear of prostomium, with three annulations; second and third annulations subequal in length, each approximately 2× as long as first annulation; second and third annulations with slightly swollen dorsal crest ( Figs. 5 B, 7A). Dorsal tentacles emerging from posterior margin of third peristomial annulation; first pair of branchiae emerging posterior to and slightly lateral to tentacular bases from asetigerous first segment fused with setiger 1; subsequent branchiae on posterodorsal margin of segments dorsal to notosetal fascicles, extending to far posterior region. Parapodia reduced to simple swollen lobes; notopodial and neuropodial lobes adjacent throughout. Notosetae of anterior region long, finely pilose capillaries, 5–7 per fascicle; long, thin spines from setiger 20 in holotype ( 16–20 in other specimens), initially with single transitional seta similar to other capillaries but with spinous tip; following setigers with 3–4 spines accompanied by 3–4 pilose capillaries, grading rapidly in subsequent setigers to anterior row of 3–5 spines accompanied by posterior row of 3–4 longer, spines ( Fig. 5 D). Neurosetal fascicles in anterior region with 6–8 pilose capillaries, spines appearing from setiger 12 in holotype ( 12–15 in other specimens); initially with three spines accompanied by three capillaries, then grading to anterior row of 3–5 spines accompanied by posterior row of 3–5 longer, more narrow spines ( Figs. 5 D, 7B); notosetal and neurosetal fascicles with reduced numbers of setae in far posterior setigers. Spines long, thin and straight with fine tip bending back and adhering to shaft ( Fig. 5 E). Methyl green staining pattern. Body uniformly light blue with anterior segments staining more intensely; anterior region with darkly staining, midventral line. Prostomium and dorsum of peristomium and asetigerous segments, as well as far posterior body region, unstained. Habitat. A widespread subtidal species in the Gulf of Nicoya, mud and sand, 9–44 m depth. Remarks. Chaetozone nicoyana sp. nov. is similar to C . curvata , C . commonalis , Chaetozone anasimus Doner & Blake, 2006 off New England , and Chaetozone allanotai Blake, 2006 from deep water off northern California, in having acicular spines with a fine recurved tip that adheres to the setal shaft. The first occurrence of these spines is much earlier in C . nicoyana sp. nov. (setigers 12–14) than in the related species, where the spines do not begin prior to setiger 40. Additionally, the double row of spines in both rami of C . nicoyana sp. nov. is unlike the single rows of spines that form partial cinctures in the posterior setigers of the related species. Etymology . The specific name refers to the common occurrence of this species subtidally in the Golfo de Nicoya.