Occurrence of the Phoronid Phoronopsis albomaculata in Cocos Island, Costa Rica.

v. ill. 23 cm.QuarterlyThe phoronid Phoronopsis albomaculata was collected in subtidal (28– 35 m) sandy sediments in Bahı´a Chatham during a benthic survey designed to describe the biota of Cocos Island (Isla del Coco), Costa Rica, a national park and Human Heritage Site. Occurrence of this widespread species in Cocos Island is the first report of a phoronid for Costa Rican waters and is the second locality recorded for the eastern Pacific. Taxonomically significant characters (presence of an epidermal collar, extent of coiling of lophophore and nephridia) are discussed. Comparisons are made between depth and abundance of this species from Cocos Island and results of previous studies

Taxonomic review of three Species of Sipuncula (Golfingiidae, Phascolosomatidae, Themistidae) from the Eastern Pacific Ocean

Based on our examination of type material plus additional specimens, it is concluded that Thysanocardia melanium Popkov is a junior synonym of the northern Pacific T. nigra Ikeda, with a tentacular crown pigmented in many but not all members of the population, and the shape of its nuchal organ may resemble a bicycle seat, a heart, or a thick-sided V. Apionsoma (Phadeonis) claviformes Popkov is shown to be a junior synonym of A. murinae bilobatae Cutler, this subgenus therefore becomes a nomen nudum. Themiste ( Themiste) maculosum Popkov is a valid new species from the Sea of Japan

Marine biodiversity of Costa Rica: Class Polychaeta (Annelida)

Three hundred and thirty two species of polychaetes belonging to 50 families are reported for Costa Rica based on previously published reports. In a few families, available material was re-examined and appropriate changes in species identifications were made. Only three species, (Glycera oxycephala Ehlers, 1887; Hemipodia pustulata (Friedrich 1956); and Scolepis (Scolepis) squamata (Müller, 1806)) have been reported from the Caribbean coast of Costa Rica, and these three species have also been reported from the Pacific Coast. The families with more than 15 species are the Spionidae (26), Cirratulidae (24), Nereididae (21), Lumbrineridae (19) and Paraonidae (16). Despite extensive sampling on the Pacific coast over the last 25 years, the Costa Rican polychaete fauna, especially that of the Caribbean coast, remains poorly knownUn total de 332 especies de poliquetos pertenecientes a 50 familias han sido informados para Costa Rica con base en publicaciones. En unas pocas familias, el material disponible fue re-examinado y se hizo los cambios apropiados en la identificación de las especies. Solamente tres especies (Glycera oxycephala Ehlers, 1887; Hemipodia pustulata (Friedrich 1956); y Scolepis (Scolepis) squamata (Muller, 1806)) han sido reportados para la costa del Caribe de Costa Rica y estas especies también están presentes en la costa Pacifica. Las familias con más de 15 especies son: Spionidae (26), Cirratulidae (24), Nereididae (21 ), Lumbrineridae (19) y Paraonidae (16). No obstante el intenso esfuerzo de colecta hecho en la costa Pacífica durante los últimos 25 años, la fauna de poliquetos de Costa Rica, especialmente la de la costa Caribe, permanece poco conocid

New Species of Cirratulidae (Annelida, Polychaeta) from the Caribbean Sea

Blake, James A., Dean, Harlan K. (2019): New Species of Cirratulidae (Annelida, Polychaeta) from the Caribbean Sea. Zootaxa 4671 (3): 301-338, DOI: https://doi.org/10.11646/zootaxa.4671.3.

Aphelochaeta striata Dean & Blake, 2016, sp. nov.

Aphelochaeta striata sp. nov. Figure 3 E, 4 B, 5 D–F Material examined. Gulf of Nicoya. Sta. 24, 9° 49 ʹ 25 ″N, 84 ° 41 ʹ 20 ″W, 11 m, sand, Oct 1980, Holotype (MCZ 132803)., Sta. 24, 9° 49 ʹ 25 ″N, 84 ° 41 ʹ 20 ″W, 11 m, sand, Oct 1980 (10), Jan 1981 (1), Aug 1981 (1), Oct 1981, 1 Paratype (MCZ 132804), Aug 1981, 1 Paratype (MCZ 132805); Sta. 29, 9° 54 ʹ 55 ″N, 84 ° 45 ʹ 15 ″W, 18 m, muddy sand, Jul 1980 (2), Oct 1980 (3), Jan 1981, 1 Paratype (MCZ 132806 (SEM)) (80), Apr 1981 (6), Jun 1981 (1), Apr 1982 (9); Sta. 30, 9° 54 ʹ 40 ″N, 84 ° 45 ʹ 50 ″W, 18 m, muddy sand, Apr 1981 (1). Description. Holotype incomplete, 5.7 mm. long, 0.3 mm wide at mid thorax for 23 setigers, paratype MCZ 132804 (dried) complete, 11.4 mm long for 114 setigers, and 0.4 mm wide; paratype MCZ 132805 2.84 mm long 0.2 mm wide in mid thorax with 24 setigers. Thoracic region narrow, twelve setigers long, dorsum somewhat flattened, ventrum rounded, remainder of body dorso-ventrally rounded in cross section; thoracic setigers three times as wide as long; remaining setigers two-thirds as wide as long. With a narrow mid-ventral groove throughout. Posterior end slightly expanded laterally, dorsally and ventrally rounded (Fig. 5 F), pygidium rounded, anus terminal. Color in alcohol white, unpigmented. Prostomium conical, with paired nuchal organs at posterior border; peristomium with two annulations; second annulation 3.5 times as long as first (Fig. 4 B), with slight posterior mid-dorsal triangular projection between tentacles emerging at posterior end of second peristomial annulation. First pair of branchiae emerging from anterior margin of setiger 1, lateral to base of dorsal tentacles; second branchial pair emerging from posterior margin of setiger 1, thus two branchiae on first setiger; subsequent branchiae emerging slightly posterior and medial to notosetae throughout. Noto- and neuropodia greatly reduced with setae emerging directly from body wall throughout (Fig. 5 D); notopodial region slightly inflated producing weak, low-lying shoulders in thoracic region. Thoracic neurosetae 10–12 per fascicle, abdominal neurosetae 5–8 per fascicle, 18–22 notosetae per fascicle in thoracic region, about 8–10 setae in abdominal fascicles; notosetae longer than neurosetae. Setae with numerous short fibrils and scattered knob-like projections along one side (Fig 5 D, E), producing a rough, irregular appearance as observed with SEM. Methyl green staining pattern. Body stains light blue; transverse blue stripes across ventrum of setigers 4–8 (Fig. 3 E). Remarks. Aphelochaeta striata sp. nov. is distinguished by the narrow body, the relatively uncrowded setigers in the thoracic region, and the first two pair of branchiae occurring on setiger 1 (Fig 4 B). Additionally, the bright blue transverse stripes of the thoracic region using methyl green staining easily identify this species (Fig. 3 E). This species is similar to Aphelochaeta elongata in having a narrow body, an elongate peristomium, uncrowded thoracic segments and transverse stripes across the ventral surface of posterior thoracic setigers. The prostomium and peristomium of A. elongata are indistinguishable and there are no visible peristomial annulations while in A. striata the prostomium and peristomium are distinct and the peristomium consists of a short anterior and long posterior annulation. The dorsal tentacles of A. elongata arise from the anterior margin of the first setiger and the first branchiae are posterior to the tentacles while in A. striata sp. nov. the first pair of branchiae are lateral to the dorsal tentacles. Additionally, there are median dorsal mounds on thoracic setigers and the posterior region is not expanded in A. elongata but A. striata sp. nov. lacks dorsal mounds and has a somewhat expanded posterior end. Aphelochaeta striata sp. nov. also shares an elongate peristomium with A. antelonga sp. nov. but that species has a larger first peristomial annulation and the prostomium is more conical than in A. striata sp. nov. The anterior setigers are more crowded and the thoracic region is wider in A. antelonga sp. nov. compared to A. striata sp. nov. Additionally, the long fibrils of the setae of A. antelonga sp. nov. are quite different than the short, beaded projections on the setae of A. striata sp. nov. Etymology. From the Latin striatum meaning striped, for the blue transverse stripes on the venter of setigers 4–8. Distribution. Collected subtidally from sand and muddy sand, 11–28 meters depth, the Gulf of Nicoya, Pacific coast of Costa Rica.Published as part of Dean, Harlan K. & Blake, James A., 2016, Aphelochaeta (Polychaeta: Cirratulidae) from the Pacific coast of Costa Rica, with a description of five new species, pp. 101-116 in Zootaxa 4103 (2) on pages 110-111, DOI: 10.11646/zootaxa.4103.2.1, http://zenodo.org/record/25913

Aphelochaeta praeacuta Dean & Blake, 2016, sp. nov.

Aphelochaeta praeacuta sp. nov. Figure 3 D, 4 A, 5 A–C Material examined. Bahia Culebra, Sta. 6, 10º 35 ʹ 35.8 ″ N, 85 º 39 ʹ 32.1 ″ W, 13 m. May 2011, Holotype (MCZ 132801); Sta. 13, 10º 36 ʹ 19.4 ″ N, 85 º 40 ʹ 59.9 ″ W, 28 m. May 2011, 1 Paratype (MCZ 132802). Description. A narrow bodied species. Holotype incomplete, 11.0 mm long, 0.8 mm at widest point in anterior abdominal region for 46 setigers; paratype incomplete, 10.3 mm long, 0.8 mm wide for 45 setigers. Thoracic region 12 setigers long, dorso-ventrally flattened, with segments 4.5 times wider than long; first 13–14 abdominal setigers widened, dorso-ventrally flattened, up to six times wider than long; subsequent abdominal segments dorsoventrally rounded, 1.3 times as wide as long. Mid-ventral groove present throughout. Far posterior region widened in holotype (Fig 5 B), dorso-ventrally flattened, grooves lacking. Pygidium absent. Color in alcohol white. Prostomium conical, with a narrow pointed tip (Fig. 4 A), directed dorsally, best seen in lateral view (Fig. 5 A); pigmented nuchal organs present at posterior border (Fig. 4 A). Peristomium with two annulations; first as long as wide, extending as a dorsal hood over second annulation, one-fourth length of first, incomplete dorsally; paired dorsal tentacles emerging at border between two peristomial annulations (Fig. 4 A, 5 A). First pair of branchiae arising on enlarged first setiger posterior to dorsal tentacles, second pair of branchiae dorsal to notosetae at posterior of setiger 1, remaining branchiae arising dorsal to notosetae throughout (Fig. 4 A), first setiger three times as wide as long, with noto- and neurosetae emerging from posterior lateral border; subsequent thoracic setigers five times as wide as long. Parapodia low, fleshy lobes, with setae emerging in a row directly from body wall. Thoracic setae all broad based with long, fine fibrils along one edge (Fig 5 C), 7–8 in notopodia, 5–8 in neuropodia; abdominal region with up to 12–13 notosetae and 10–12 neurosetae, both broad, fibrillated setae and shorter, thin capillaries apparently lacking emergent fibrils. Swollen far posterior pre-pygidial region two times as long as wide (Fig. 5 B). Methyl green staining pattern. Dorsum of thoracic region staining dark blue, remainder of body lighter blue; prostomium unstained (Fig. 3 D). Remarks. The relatively large first peristomial annulation extending as a dorsal crest above the second annulation, the darkly pigmented nuchal organs, and the enlarged first setiger bearing the first two pairs of branchiae help to recognize this species. Additionally the lack of well-developed shoulders over the thoracic parapodia is shared with only A. phillipsi Blake, 1996 and A. antelonga sp. nov., both of which have smooth setae. A. bullata Doner & Blake, 2009 also has a similar posteriorly extended dorsal crest and the first setiger is somewhat enlarged but the prostomium and peristomium of that species are inflated and bulbous with a rounded prostomial tip, while A. praeacuta sp. nov. has a narrow anterior end and a sharply pointed prostomium. Additionally, the long fine fibrils on the capillaries of A. praeacuta sp. nov. are different from the smooth capillaries of A. bullata. Aphelochaeta antelonga sp. nov. also has capillary setae with fibrils but the fibrils are not as fine while the elongate anterior region is much different from that of A. praeacuta sp. nov. The biannulate peristomium of this species is also seen in A. multifilis (Moore, 1909), and perhaps A. petersenae Blake, 1996 and A. williamsae Blake, 1996 (although these latter two species are described as having 2–3 peristomial annulations) but fibrillated setae are not reported for these species. A. striata sp. nov., described below, also has two peristomial annulations but the prostomium/peristomiun is much longer in that species and the thoracic segments are not as crowded. Etymology. From the Latin, praeacutus which means sharp, pointed front or anterior, for the sharply pointed, almost digitate, nature of the prostomium. Distribution. Collected subtidally from sandy sediments at 13 and 28 meters depth from Bahia Culebra, Pacific coast of Costa Rica.Published as part of Dean, Harlan K. & Blake, James A., 2016, Aphelochaeta (Polychaeta: Cirratulidae) from the Pacific coast of Costa Rica, with a description of five new species, pp. 101-116 in Zootaxa 4103 (2) on pages 108-110, DOI: 10.11646/zootaxa.4103.2.1, http://zenodo.org/record/25913

The Orbiniidae (Annelida: Polychaeta) of Pacific Costa Rica

Dean, Harlan K., Blake, James A. (2015): The Orbiniidae (Annelida: Polychaeta) of Pacific Costa Rica. Zootaxa 3956 (2): 183-198, DOI: http://dx.doi.org/10.11646/zootaxa.3956.2.

Aphelochaeta glandaria Blake 1996

Aphelochaeta glandaria Blake, 1996 Figures 2 C, 3 B Aphelochaeta longisetosa: Dean 1996 a (in part). Not Hartmann-Schröder, 1965. Aphelochaeta glandaria: Dean 2004 (in part). Not Blake, 1996. Material examined. Gulf of Nicoya. Sta. 24, 9° 49 ʹ 25 ″N, 84 ° 41 ʹ 20 ″W, 11 m, sand, Oct 1980 (2); Sta. 29, 9° 54 ʹ 55 ″N, 8445 ʹ 15 ″W, 18 m, muddy sand, Jul 1980 (15, MCZ 132979 (SEM)), Jun 1981 (1), Apr 1982 (2); Sta. 30, 9° 54 ʹ 40 ″N, 84 ° 45 ʹ 50 ″W, 18 m, muddy sand, Apr 1981 (2). Golfo Dulce, Sta. GD–03, 8 ° 35 ʹN, 83 ° 16 ʹW, 200 m, soft black mud, Dec 1993. Col. R. León-Morales & J.A. Vargas (1). Description. Robust species with uniformly wide body with a slightly expanded thorax. Complete specimen 10.2 mm long, 1.6 mm wide for 167 segments, Dorsum of thorax rounded, swollen, venter flat with numerous minute glands producing creamy white region extending onto anterior abdomen, with mid-ventral groove only on last thoracic setigers; abdominal setigers approximately six times as wide as long, oval in cross section, about 1.5 times as wide as high, with mid-ventral groove; expanded posterior region 2.0 mm wide with 35 crowded setigers up to 14 times wider than long, with mid-dorsal and mid-ventral groove; pygidium a short rounded lobe ventral to anal opening. Color in alcohol light yellow-brown with thoracic and anterior abdominal region creamy white ventrally. Prostomium pointed, conical, about as wide as long; peristomium slightly longer than wide, with three welldifferentiated annulations, often deeply cleft dorso-laterally at junctions between annulations (Fig. 3 B), weak dorsal crest present extending along dorsum of first three or four thoracic setigers as narrow ridge; paired dorsolateral nuchal organs on posterior edge of prostomium; dorsal tentacles arise from peristomium, which extends over dorsum of setiger 1, just anterior to setiger 2. First branchiae dorsal to notosetae of setiger 1 lateral to dorsal tentacles; subsequent branchiae also dorsal to notosetae. Thoracic parapodia well developed dorso-lateral lobes with notopodia forming shoulders; setae emerge ventro-laterally from slightly swollen regions of body wall in abdominal segments. Noto- and neuropodia close to one another throughout. Setae all capillaries with notosetae 2–3 times longer than neurosetae; with 10–12 notosetae and 6–8 neurosetae in thoracic region, 8–10 setae per fascicle in each ramus in abdominal region, reduced in number in far posterior setigers, notosetal and neurosetal fascicles somewhat separate throughout. Long capillary setae rounded in cross section with short fibrils along one side, shorter setae more flattened with minute fibrils along one edge (Fig. 2 C). Methyl green staining pattern. Dorsum of peristomium with scattered blue speckles, greatest density of speckles on peristomium at base of tentacles, extending as a diagonal streak ventrally from lateral edge of dorsal tentacles (Fig. 3 B). Anterior thoracic region with weak blue stain on venter; remainder of body light blue-green; pygidium and prostomium unstained. Remarks. The cream colored thoracic venter makes this species easily identifiable in benthic samples. The many crowded setigers, the wide thoracic region, and expanded posterior end with both a dorsal and ventral groove are all easily recognizable characters. The microscopic fibril endings on the otherwise smooth capillary setae (Fig. 2 C), which were noticed by Blake (1996), are also visible using light microscopy in the Costa Rican specimens. Blake (1996) indicated that this species may either have a wide geographic range or be a complex of sibling species as morphologically similar specimens have been reported from northern Europe, the eastern United States and Australia. Comparison of the Costa Rican specimens with paratypes of A. glandaria from California show similar staining patterns but differences in staining intensity, perhaps due to differences in fixation. Distribution. Collected in 11–18 m from muddy sand to sandy sediments in the Gulf of Nicoya. This species was previously collected at 76–410 m in the Santa Maria Basin and Western Santa Barbara Channel off California, USA. The presence of this species in the Gulf of Nicoya extends the range of this species from central and southern California to Pacific Costa Rica.Published as part of Dean, Harlan K. & Blake, James A., 2016, Aphelochaeta (Polychaeta: Cirratulidae) from the Pacific coast of Costa Rica, with a description of five new species, pp. 101-116 in Zootaxa 4103 (2) on pages 104-106, DOI: 10.11646/zootaxa.4103.2.1, http://zenodo.org/record/25913

On Branchiostoma californiense (Cephalochordata) from the Gulf of Nicoya estuary, Costa Rica

The cephalochordates are represented by the lancelets, of which species of the genus Branchiostoma are the best known. In recent years, these organisms have been the center of activity of studies focusing on the phylogenetic relationships of the chordates. In 1980, a survey of the benthos at 48 stations in the Gulf of Nicoya estuary, Pacific coast of Costa Rica, yielded 265 specimens of the lancelet Branchiostoma californiense. A total of 48 specimens was also collected at an intertidal flat in the mid upper estuary. Of the 48 subtidal stations, only eight had B. californiense, and these sites all had a sand fraction above 72%. The remaining stations ranged in their sand content from as low as 1% to as high as 92%, with an average of 25.9%, with 29 stations having a sand content lower than 72%. Lower salinities and muddy sediments may limit the distribution of the lancelet further upstream. This information is useful when changes over decades in the ecology of the estuary need to be evaluated against the background of local, regional, and global dynamics. Rev. Biol. Trop. 58 (4): 1143-1148. Epub 2010 December 01.<br>Los cefalocordados están representados por los anfioxos, de los que especies del género Branchiostoma son los más conocidos. En los últimos años, estos organismos han sido muy estudiados, principalmente sus relaciones filogenéticas. Durante 1980, realizamos un muestreo del bentos en 48 estaciones del Golfo de Nicoya, costa Pacífica de Costa Rica y reportamos 265 ejemplares del anfioxo, Branchiostoma californiense. También recolectamos un total de 48 individuos en una planicie fangosa de la zona entre mareas de la región superior media del estuario. De las 48 estaciones solamente en ocho encontramos especímenes de B. californiense y estos sitios tenían un porcentaje de arena superior al 72%. Las otras estaciones tenían un porcentaje de arena en un ámbito tan bajo como 1% y tan alto como 92%, con un promedio de 25.9%, 29 estaciones presentaron un porcentaje de arena menor de 72%. Salinidades bajas y sedimentos fangosos pueden limitar la distribución del anfioxo en la región superior del estuario. Esta información es de utilidad cuando se desea evaluar los cambios en la biodiversidad y la ecología del estuario a largo plazo en el contexto de la dinámica local, regional o global

Aphelochaeta zebra Dean & Blake, 2016, sp. nov.

Aphelochaeta zebra sp. nov. Figures 3 F, 4 C–D, 6 B Material examined. Golfo Dulce; Coral reef, Punta Islotes, 8 ° 43 ʹ 41 ″N; 83 ° 23 ʹ 8 ″W. Col: Ana Fonseca by SCUBA, Holotype (MCZ 132807). Description. Holotype complete, in two pieces (anterior 17. 2 mm, posterior 2.2 mm), 19.4 mm long for 154 setigers, thoracic width 0.7 mm, abdomen 0.4 mm wide, swollen posterior end 0.6 mm wide. Thoracic region with 22 crowded segments 25–30 times wider than long, dorsum inflated, dome-like (Fig. 4 C, D), venter flattened with mid-ventral line, groove absent; abdominal segments of uniform width, approximately two times as wide as long, rounded dorsally, flattened ventrally, first 21 abdominal setigers with narrow mid-ventral groove, subsequent setigers with mid-ventral line, groove absent; posterior end inflated dorso-ventrally, with 29 setigers; pygidium with small dorsal and ventral lobes (Fig. 3 F). Color in alcohol brownish yellow. Prostomium short, rounded, nuchal organs not apparent, prostomium retracted into peristomium; peristomium short, wider than long, with three annulations, anterior annulation approximately one-half length of two posterior annulations, with short, narrow, median dorsal ridge on posterior annulations (Fig. 4 D); dorsal tentacles emerging from posterior margin of peristomium. First pair of branchiae immediately lateral to dorsal tentacles on anterior edge of setiger 1; subsequent thoracic branchiae at posterior border of notopodial lobe at medial surface of shoulders, gradually moving closer to, and becoming adjacent to notosetae by setiger 10; abdominal branchiae emerging from conical notopodial lobe dorsal to notosetae. Thoracic parapodia swollen lobes forming weak shoulders along lateral surface of body, notosetae emerging from apex of elevated shoulder, neurosetae from slightly elevated cone ventral to notopodia; abdominal notosetae emerging apically from short, cone-like projections, neurosetae emerging from body wall at base of notopodial cone. Setae long, smooth capillaries, with minute, ragged-edged scale-like structures visible with SEM (Fig. 6 B); thoracic parapodia with up to seven setae in each fascicle; abdominal segments with up to 24 notosetae and seven neurosetae, reducing to eight notosetae and four neurosetae in far posterior; swollen posterior end with up to five notosetae and three neurosetae, reducing in number posteriorly. Methyl green staining pattern. Body staining dull greenish-grey, ventral groove of posterior thoracic region dark green, pygidium unstained; swollen posterior region with intersegmental lines staining dark green providing a striped zebra-like pattern (Fig. 3 F). Remarks. Aphelochaeta zebra sp. nov. is similar to A. multifilis in having a broadly rounded prostomium, a relatively broad peristomium and a robust body throughout. However, the posterior end of A. multifilis is inflated with paired ventral grooves while that of A. zebra sp. nov. is more greatly inflated, possesses only a single midventral groove, and has a distinctive, striped methyl green staining pattern within the intersegment grooves. This striped staining pattern on the swollen posterior region of A. zebra sp. nov. is somewhat similar to that of A. tigrina Blake, 1996 but in A. tigrina the staining occurs on the entire ventral surface of individual setigers except for the intersegmental region while in A. zebra sp. nov. staining does not occur in the median area of each setiger but stains intensely in the intersegmental grooves. Aphelochaeta zebra sp. nov. shares a shortened anterior region, a triannulate peristomium, crowded thoracic segments and smooth setae with A. guttata Doner & Blake, 2009 but the first branchiae occur on the peristomium in that species while they occur on setiger one in A. zebra sp. nov. Etymology. The species name is from the Portuguese zebra meaning wild ass and refers to the striking methyl green staining pattern of the swollen posterior end. Distribution. Known only from a coral reef at Punta Islotes, Golfo Dulce, Costa Rica.Published as part of Dean, Harlan K. & Blake, James A., 2016, Aphelochaeta (Polychaeta: Cirratulidae) from the Pacific coast of Costa Rica, with a description of five new species, pp. 101-116 in Zootaxa 4103 (2) on pages 111-113, DOI: 10.11646/zootaxa.4103.2.1, http://zenodo.org/record/25913