Prionospio cristata Foster, 1971

Delgado-Blas, Víctor Hugo, 2015, Prionospio (Polychaeta, Spionidae) from the Grand Caribbean Region, with the descriptions of five new species and a key to species recorded in the area, Zootaxa 3905 (1), pp. 69-90 : 78-81

Prionospio cristata Foster, 1971

Figure 4 A – L

Prionospio cristata Foster, 1971:87 , Figs. 186–199.

Prionospio (Prionospio) cristata: Johnson, 1984 :6.51, Figs. 6.42a–e. Prionospio (Prionospio) cristata Maciolek, 1985:340 –341, Fig. 4 .

Material examined. GULF OF MEXICO. Veracruz: 20 July 1982, coll. FEDH, 8 specimens (ECOSUR-P1411); Yucatan: Celestun lagoon, 20º48’12.2’’N, 90º24’7.5’’W, 0.53 m, 15.6 ‰, 26 ºC, 7.9 pH, 2.1 org. carb. BOR 2, 15 February 2008, 1 specimen (ECOSUR-P2727). CARIBBEAN SEA. Quintana Roo: E43, APEMEX, Yalahau, 18 January 1991, 3 specimens, coll. J. Oliva Rivera and M. Esquivel Moreno (ECOSUR-P2728); 19 February 2001, Aventuras Beach, Quintana Roo, 20º15'31.56"N, 87º23'47.50"W, sandy beach well-sorted sand, 0.3 m, 1 specimen, coll. Leslie H. Harris, Harris, LH01-450 (LACM-AHF Poly 6224); Aventuras Beach, coll. F. Pleijel, 18 February 2001, 5 specimens (ECOSUR-P1414); Punta Nizuc, Cancún, Coll. V.H. Delgado Blas, 10 February 2001, 1 specimen (ECOSUR-P1412); Santa Cecilia, coll. SISV, 4 November 1990, 1 specimen (ECOSUR-P1413).

Description. Complete specimens, 12.0–14.0 mm long for 59–65 chaetigers, 0.4–0.5 mm wide. Incomplete specimens, 2.5–3.0 mm long for 18–23 chaetigers, 0.3–0.5 mm wide. Color in alcohol opaque white. Prostomium subtriangular, rounded anteriorly ( Fig. 4 A), posteriorly tapered, with short, blunt caruncle extending to the middle edge of chaetiger 2 with large nuchal organs on either side ( Fig. 4 A). Two pairs of brown subdermal eyes, arranged in a trapezoid; anterior pair small, rounded; posterior pair large, crescent-shaped ( Fig. 4 A) (one specimen lacking eyes). Palps lost. Peristomium short, collar-like, surrounding the prostomium, fused dorsally with large rounded notopodial lamellae of chaetiger 1. Neuropodial postchaetal lamellae of chaetiger 1 moderate, rounded ( Fig. 4 E), much smaller than twice the size of the notopodial lamellae.

Four pairs of long branchiae present on chaetigers 2–5 ( Fig. 4 A); first pair longer than fourth pair. Pairs 1 and 4 with long, slender, dense digitiform pinnules ( Fig. 4 A), arranged along the posterior face of the stems; branchiae with very long, naked, smooth distal tips; basal region of branchiae naked; distribution of the pinnules similar on both pairs; pinnules slender, long, blunt in middle and basal regions of the branchiae ( Fig. 4 A); the central stem of branchial pairs 1 and 4 pinnate and elongate. Pairs 2 and 3 apinnate, cirriform, long, with sparse lateral ciliation and acute distal tips ( Fig. 4 A); subequal in length, shorter than pinnate pairs and longer than notopodial lamellae.

Notopodial postchaetal lamellae foliaceous and wider on chaetigers 2–6 ( Fig. 4 A), slightly cupped and facing somewhat antero-laterally; largest on chaetigers 3–4 with acute, long tips, progressively decreasing in size, becoming rounded on chaetigers 7–10 ( Fig. 4 B); decreasing in size in subsequent chaetigers and short on posterior chaetigers ( Fig. 4 C). High dorsal crests present on chaetigers 7–9, slightly shorter on chaetiger 8 ( Fig. 4 D), subsequent chaetigers lacking folds. Ventral and dorsal edges of notopodial and neuropodial lamellae on anterior chaetiger neither overlapping nor touching. Notopodial prechaetal lamellae fused with postchaetal lamellae; large in branchial region, short thereafter.

Neuropodial postchaetal lamellae rounded throughout ( Fig. 4 E, F), except the neuropodium of chaetiger 3 which is slightly angled and trapezium-shaped, dorsally directed ( Fig. 4 G), larger than the other neuropodial lamellae; pairs 1–3 cupped and facing somewhat antero-laterally; subsequent neuropodial lamellae small on far posterior chaetigers. Prechaetal lamellae moderate ( Fig. 4 E), short throughout. Interparapodial pouches lacking.

All capillaries on anterior chaetigers granulated, unilimbated ( Fig. 4 H, I); notopodial and neuropodial capillaries of chaetiger 1 arranged in one row, with short, slender chaetae; notopodial chaetae longer. Notopodial capillaries of chaetigers 2–13 arranged in two rows, very long and very acute ( Fig. 4 H), upper chaetae much longer than lower ones, chaetae curving outwards and upwards, becoming shorter later. Neuropodial capillaries of chaetigers 2–10 arranged in two rows, capillaries very long and very acute ( Fig. 4 I) with the anterior row shorter than the posterior row, later becoming one row. Notopodial and neuropodial capillaries of middle and posterior chaetigers alimbate and without granulations. Sabre chaetae in neuropodia from chaetiger 10, up to two per fascicle, stout, curved, moderately granulated, without sheaths ( Fig. 4 J). Neuropodial hooded hooks ( Fig. 4 K) from chaetigers 12–13, up to seven per fascicle, accompanied by capillaries. Notopodial hooded hooks ( Fig. 4 L) from chaetigers 26–34, up to five per fascicle, accompanied by up to two capillaries. All hooks with four pairs of teeth above main tooth, with short secondary hoods ( Fig. 4 K, L).

Pygidium with one long median cirrus and two longer lateral lobes.

Remarks. The above description agrees closely with the original description given by Foster (1971), however there are a few differences, in that in Foster’s (1971) description the prostomium is subtriangular or wedge-shaped with the anterior border blunt to slightly rounded; all capillaries on the anterior chaetigers are bilimbated; the posterior capillaries are unilimbated and the sabre chaetae are sheathed. Whereas, in the specimens in this study, the prostomium is subtriangular and very rounded anteriorly; all the capillaries are unilimbated and the sabre chaetae lack sheaths. There are also a few differences between the specimens examined in this study and the description given by Johnson (1984) in that in the latter the sabre chaetae are sheathed, whereas in this study the sabre chaetae lacked sheaths. There are a few further differences with the description of this species given by Maciolek (1985) in that Maciolek described the prostomium as having horseshoe-shaped nuchal organs with the anteriormost ends fused over the caruncle, and the sabre chaetae as having sheaths, whereas in this study the specimens have a prostomium with nuchal organs either side of the caruncle and fused above it, and the sabre chaetae lack sheaths. Another discrepancy lies in where the neuropodial and notopodial hooded hooks appear.

According to Foster (1971), the neuropodial and notopodial hooks should be present from chaetigers 11–12 and 21–37, whereas Johnson (1984) states that they begin on chaetigers 10–12 and 26–30, and Maciolek (1985) 10–13 and 21–37. In contrast, the material examined here had neuropodial hooks from chaetigers 12–13 and notopodial hooded hooks from chaetigers 26–34; this could, however, be due to the size of the specimens. The differences between P. cristata and the other species examined are provided in the key and Table 1.

Geographical distribution. North Atlantic; Delaware, North Carolina, Florida; Gulf of México: Port Aransas, Texas, Veracruz, Yucatán, Caribbean Sea: Quintana Roo, Puerto Rico, Curaçao.

Figures

FIGURE 4. Prionospio cristata Foster, 1971. Non-type (ECOSUR-P 1414): (A) anterior region, dorsal view; (B) notopodium of chaetiger 10; (C) notopodium of posterior chaetiger; (D) high dorsal crests on chaetigers 7 – 9; (E) neuropodial lamellae of chaetigers 1 – 2; (F) neuropodial lamellae of chaetigers 5 – 6; (G) neuropodial lamellae of chaetiger 3; (H) anterior notopodial chaeta; (I) anterior neuropodial chaeta; (J) sabre chaeta; (K) neuropodial hooded hook; (L) notopodial hooded hook. Scale bars: A, D 400 µm; B – C, E – G 200 µm; H – J 100 µm; K – L 25 µm.