Prionospio parapari, elgado-Blas, Victor Hugo, iaz-Diaz, Oscar & ieitez, Jose M., 2018

elgado-Blas, Victor Hugo, iaz-Diaz, Oscar & ieitez, Jose M., 2018, Prionospio from the coast of the Iberian Peninsula, with the description of two new species (Annelida, Spionidae), ZooKeys 810, pp. 1-18 : 9-11

Prionospio parapari sp. n. Figure 4 A–Z

Material examined.

Atlantic Ocean. Holotype (MNCNM 16.01/18433), Mouth of Piedras River, Huelva: St. D24, 37°12'53"N, 7°7'8"W, coll. L Lopez-Serrano, March 1988. 8 Paratypes (anterior fragments) (MNCNM 16.01/18434), St. D22, 37°12'42"N, 7°9'8"W, coll. L Lopez-Serrano, November 1987; 6 paratypes (MNCNM 16.01/18435), St. D24, 37°12'53"N, 7°7'8"W, coll. L Lopez-Serrano, March 1988; 2 paratypes (MNCNM 16.01/18436), St. D25, 37°12'53"N, 7°7'57"W, coll. L López-Serrano, March 1988; 2 paratypes and anterior fragments (MNCNM 16.01/18437), St. D29, 37°6'50"N, 7°4'0"W, coll. L Lopez-Serrano, May 1988; 1 paratype and 4 anterior fragments (MNCNM 16.01/18438), St. D38, 37°12'45"N, 7°5'57"W, coll. L Lopez-Serrano, November 1988. Coruña: 1 paratype (MNCNM 16.01/12588), Ria de Ferrol, Batel Bay, 1 February 2010, coll. J Parapar; 1 paratype (MNCNM 16.01/12569), coll. J Parapar; 64 paratypes (MNCNM 16.01/125701); 1 paratype (MNCNM 16.01/12572), 43°29'9"N, 08°15'15"W; 1 paratype (MNCNM 16.01/12573), 43°29'31"N, 8°10'44"W; 6 paratypes (MNCNM 16.01/12574), 43°27'38"N, 08°12'14"W; 5 paratypes (MNCNM 16.01/12577), 43°28'51"N, 8°11'13"W; 4 paratypes (MNCNM 16.01/12578); 2 paratypes (MNCNM 16.01/12579); 1 paratype (MNCNM 16.01/12580), 43°29'7"N, 8°10'19"W; 1 paratype (MNCNM 16.01/12582), 43°28'46"N, 8°11'45"W; 1 paratype (MNCNM 16.01/12583), 43°28'31"N, 8°12'14"W; 1 paratype (MNCNM 16.01/12589), 43°28'2"N, 8°16'37"W; 6 paratypes (MNCNM 16.01/12575), 43°28'51"N, 8°15'15"W; 1 paratype (MNCNM 16.01/15810); 1 paratype (MNCNM 16.01/15802); 1 paratype (MNCNM 16.01/15800); 1 paratype (MNCNM 16.01/15811), Ria de Ferrol, Laxe Bay, coll. J Parapar; Ria de Ferrol, Redonda Point, coll. J Parapar.

Description.

Holotype complete, 18.0 mm long with 62 chaetigers, 0.4 mm wide. Complete paratypes, 17.0-21.0 mm long with 47-68 chaetigers, 0.2-0.8 mm wide. Incomplete paratypes, 4.0-12.5 mm long with 14-61 chaetigers, 0.2-0.5 mm wide. Color in alcohol pale white. Prostomium bottle-shaped, truncated and narrow anteriorly, widening in mid-region (Fig. 4A), posteriorly tapered, with long, blunt caruncle extending to anterior edge of chaetiger II (Fig. 4A); caruncle with large V-shaped nuchal organs on either side (Fig. 4A, B). Two pairs of brown-black subdermal eyes (holotype brown), arranged in a trapezoid; anterior pair small, posterior pair very large, both pairs crescent-shaped (Fig. 4A, B) (one specimen lacks eyes). Palps lost. Peristomium moderate in size, collar-like, surrounding prostomium, fused dorsally with large, rounded notopodial lamellae on chaetiger I (Fig. 4A, C). Neuropodial postchaetal lamellae on chaetiger I large, rounded (Fig. 4C), less than half the size of notopodial lamellae.

Four pairs of branchiae present on chaetigers II–V (Fig. 4B, C); first pair longer than fourth pair, up to 1 time and a half longer than the fourth pair. Pairs 1 and 4 with long, slender, dense digitiform pinnules arranged along posterior face of the stems, pinnules thick, long, blunt in middle region of branchiae (Fig. 3B); branchiae with very long, naked, smooth, distal tips (Fig. 4B). Pairs 2 and 3 apinnate, cirriform, long, densely ciliated laterally, with pointed tips (Fig. 4E, F); subequal in length, up to 3 times shorter than pinnate pairs, but longer than notopodial lamellae (Fig. 4B, E, F).

Notopodial postchaetal lamellae triangular and slender on chaetigers II–VI (Fig. 4 D–H); largest on chaetigers III–IV, with short triangular tips (Fig. 4E, F); becoming wider on chaetigers V–VI (Fig. 4G, H) and thereafter progressively decreasing in size; small, rounded on middle and posterior chaetigers (Fig. 4I, J). Notopodial lamellae united across dorsum, forming a high dorsal crest on chaetiger VII and low dorsal crests on chaetigers VIII–IX (Fig. 4A); some specimens without dorsal crests on chaetiger IX, subsequent chaetigers lacking crests. Ventral and dorsal edges of notopodial and neuropodial lamellae touch only on chaetiger III (Fig. 4E). Notopodial prechaetal lamellae moderate and oval in branchial region (Fig. 4 E–G), not basally fused with notopodial postchaetal lamellae, inconspicuous thereafter (Fig. 4 H–J).

Anterior neuropodial postchaetal lamellae rounded (Fig. 4C, F–H) throughout, except on chaetigers II–III; lamella on chaetiger II triangular, large, with ventral edge enlarged, pointed (Fig. 4D); lamella on chaetiger III oval with dorsal edge enlarged (Fig. 4E); second and third pairs larger than other neuropodial lamellae; subsequent neuropodial lamellae small and rounded on middle chaetigers (Fig. 4I), and rounded lobes on posterior chaetigers (Fig. 4J). Neuropodial prechaetal lamellae low in anterior region (Fig. 4 C–H), rudimentary throughout. Interparapodial pouches lacking. All anterior and middle notopodial chaetae arranged in two rows. Notochaetae on chaetigers I–IX heavily granulated, unilimbate (Fig. 4K, L); posterior row longer, more heavily granulated (Fig. 4L) than anterior row (Fig. K); both rows of chaetae on middle notopodia thin, smooth, unilimbate (Fig. 4M, N); anterior row shorter (up to half) (Fig. 4M) than posterior row (Fig. 4N); posterior notopodia with smooth, alimbate chaetae (Fig. 4O) arranged in one row. All neuropodial capillaries arranged in two rows; capillaries on chaetiger I slightly granulated, unilimbate (Fig. 4P); chaetigers II–IX with heavily granulated, unilimbate neurochaetae (Fig. 4Q, R); posterior row more heavily granulated (Fig. 4R), with limbation wider than for notochaetae. Neurochaetae smooth, unilimbate on subsequent chaetigers, those on anterior row up to three times shorter and wider (Fig. 4S) than those on posterior row; limbation of posterior row wider than that of the anterior one (Fig. 4T); chaetae on posterior neuropodia arranged in one row. Neuropodial sabre chaetae from chaetigers X–XII (holotype X), up to two per fascicle, each chaeta stout, curved, heavily granulated, bilimbate (Fig. 4U). Neuropodial hooded hooks (Fig. 4V, V') from chaetigers XI–XV (holotype XIII), up to eight per fascicle, alternating with long, thin, alimbate capillaries (Fig. 4W). Notopodial hooded hooks on chaetigers XXIX–XXXVIII (holotype XXXIII), up to six per fascicle, alternating with up to two thin, alimbate capillaries, hooks on posterior chaetigers longer than those on middle chaetigers; all hooks with four pairs of small teeth above main tooth, and large secondary hoods (Fig. 4V, V').

Pygidium with one long median cirrus and two short, lateral lobes (Fig. 4X).

Remarks.

Prionospio parapari sp. n. is very similar to P. fallax in having a prostomium that is truncated on the anterior margin, a neuropodial postchaetal lamellae on chaetiger II being the same shape, and a high dorsal crest on chaetiger 7. However, P. parapari sp. n. can be distinguished from P. fallax as redescribed by Sigvaldadóttir and Mackie (1993), by the former having rounded (rather than rectangular) postchaetal neuropodial lamellae on chaetiger I, the first pair of branchiae longer than fourth (rather than of equal size), and with dense digitiform (rather than sparse lateral) pinnules arranged along the posterior face of the stems on branchiae 1 and 4, and cirriform (rather than subtriangular) second and third branchial pairs. In addition, the low dorsal crests in P. parapari sp. n. are present on chaetigers VIII–IX while in P. fallax they are absent; the neuropodium on chaetiger III in P. parapari sp. n. is oval with an enlarged dorsal edge whilst in P. fallax it is subtriangular and dorsally pointed; and the sabre chaetae in P. parapari sp. n. are heavily granulated and bilimbate whereas in P. fallax they are distally granulated and alimbate. The pygidium lacks pigmentation in P. parapari .

Prionospio parapari sp. n. is also similar to P. komaeti Hylleberg & Nateewathana, 1991, P. depauperata Imajima, 1990, and P. oligopinnulata Delgado-Blas, 2015, in that all three species have a prostomium that is truncated on the anterior margin, the same shaped neuropodial postchaetal lamellae on chaetiger II, and a high membranous dorsal crest on chaetiger VII that decreases in height on chaetigers VIII–IX. However, P. parapari sp. n. differs from the first two species in that it has rounded (rather than square or lanceolate) notopodial and neuropodial postchaetal lamellae on chaetiger I, and an oval neuropodium on chaetiger III with the dorsal edge enlarged (rather than one that is square or triangular). In addition, the branchiae of P. parapari sp. n. have long, naked, smooth distal tips, whereas those of P. komaeti and P. depauperata have pinnules extending to the distal end, and P. parapari lacks low dorsal crests on chaetigers X–XI /XIII. Prionospio parapari sp. n. also differs from P. depauperata in that it has sabre chaetae without a distal filament, the notopodial hooded hooks start on chaetigers XIX–XXXVIII rather than XLV–XLVII, and the pygidium has two long lateral lobes rather than two short lateral cirri. Furthermore, P. parapari sp. n. is similar to P. oligopinnulata in that both species show the same pygidial structure, but differs in having cirriform rather than triangular second and third branchial pairs. In addition, the low dorsal crests on chaetigers X–XIV are absent in P. parapari sp. n., the neuropodium on chaetiger III is oval with the dorsal edge enlarged (rather than subtriangular and ventrally pointed), and the sabre chaetae are bilimbate (rather than alimbate). Prionospio parapari sp. n. is similar to P. rotunda Delgado-Blas, 2015 in that both species have large, rounded neuropodial postchaetal lamellae on chaetiger I, cirriform second and third branchial pairs, the first branchial pair always longer than fourth pair, and the same pygidium structure. However, P. parapari sp. n. differs from P. rotunda in having a bottle-shaped prostomium that is truncated on the anterior margin (rather than a pyriform and rounded one). In addition, the low dorsal crests in P. parapari sp. n. are present on chaetigers VIII–IX whereas in P. rotunda they are absent, and the neuropodium on chaetiger III is oval with an enlarged dorsal edge (rather than rounded). The differences between this new species and the other species examined are provided in the key.

Etymology.

The species is named in honor of Dr Julio Parapar, in recognition of his major contribution to the study of polychaetes from Spanish coasts.

Type locality.

Ría de Ferrol and the mouth of Piedras River, Huelva, Spain.

Distribution.

To date, this species has been recorded only on the Spanish Atlantic coast (Ria de Ferrol and the mouth of Piedras River, Huelva).