Prionospio oligopinnulata , Delgado-Blas, Víctor Hugo, 2015

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: 84-87

publication ID

http://dx.doi.org/10.11646/zootaxa.3905.1.4

publication LSID

lsid:zoobank.org:pub:6C454B4B-E32D-4B55-B195-32A575BCC858

persistent identifier

http://treatment.plazi.org/id/039D3B4F-8132-125A-FF3A-D9A8F73EFE4E

treatment provided by

Plazi

scientific name

Prionospio oligopinnulata
status

sp. nov.

Prionospio oligopinnulata  sp. nov.

Figure 7View FIGURE 7 A– R

Type material. GULF OF MEXICO. Campeche: Off Campeche, E46, 20º 14 'N, 91 º05'W, Dinamo I, 17 m, 27 ºC, 36.8 ‰, sand, 2 February 1990, holotype ( CNAP-ICML, UNAMAbout UNAM: POH-09-002); off Campeche, E46, 20º 14 'N, 91 º05'W, Dinamo I, 17 m, 27 ºC, 36.8 ‰, sand, 2 February 1990, 2 paratypes ( CNAP-ICML, UNAMAbout UNAM: POP-09- 003).

Non-type material. GULF OF MEXICO. Yucatan: Off Celestún, E30, 21º02'N, 91 º05'W, Dinamo II, 31 m, 27.5 ºC, 36.8 ‰, sand, 30 October 1990, 2 specimens ( CNAP-ICML, UNAMAbout UNAM: PO-09-063).

Description. Holotype incomplete, 5.0 mm long for 38 chaetigers, 0.3 mm wide. Paratypes complete, 4.5–5.2 mm long for 38–40 chaetigers, 0.2–0.25 mm wide. Color in alcohol pale white. Prostomium square-shaped, truncate anteriorly ( Fig. 7View FIGURE 7 A), posteriorly tapered with short, blunt, prominent caruncle, middle slit along caruncle ( Fig. 7View FIGURE 7 A, C); caruncle extending to the anterior edge of chaetiger 2, longer than prostomium ( Fig. 7View FIGURE 7 A), with long, wide, ciliate nuchal organs ( Fig. 7View FIGURE 7 B, C) on either side ( Fig. 7View FIGURE 7 A, C). Two pairs of red-brown subdermal eyes, both pairs cup-shaped ( Fig. 7View FIGURE 7 A), arranged in a trapezoid; anterior pair small, posterior pair large and elongated ( Fig. 7View FIGURE 7 A) (holotype without eyes). Palps lost. Peristomium short ( Fig. 7View FIGURE 7 A – C), collar-like, surrounding prostomium, fused dorsally with moderately rounded notopodial lamellae on chaetiger 1 ( Fig. 7View FIGURE 7 A, C). Neuropodial postchaetal lamellae of chaetiger 1 moderate, rounded ( Fig. 7View FIGURE 7 A), much smaller than twice the size of the notopodial lamellae.

Four pairs of long branchiae present on chaetigers 2–5 ( Fig. 7View FIGURE 7 B, C). First and fourth pairs longest ( Fig. 7View FIGURE 7 B, C), generally first pair longer: up to 5 times the size of the fourth pair, but pairs 1 and 4 sometimes equal in length; pairs 1 and 4 with a few short, digitiform pinnules on the lateral face, branchiae with long naked, smooth distal tips ( Fig. 7View FIGURE 7 B, C). Distribution of pinnules on these two pairs similar, pinnules few, sparsely distributed in the middle of the branchiae ( Fig. 7View FIGURE 7 B, C); central stems of pairs 1 and 4 of the branchiae pinnate, elongate, pair 1 slightly ciliated laterally ( Fig. 7View FIGURE 7 B). Pairs 2 and 3 apinnate, triangular, narrow, with dense lateral ciliation and sharp tips ( Fig. 7View FIGURE 7 B, C); subequal in length, shorter than the pinnate pairs, but longer than the notopodial lamellae ( Fig. 7View FIGURE 7 B, C).

Notopodial postchaetal lamellae triangular, slender on chaetigers 2–6, with wide bases, thin from half way up and elongated ( Fig. 7View FIGURE 7 B, D, E), largest on chaetigers 3–4; lamellae of chaetiger 7 subtriangular with blunt tips ( Fig. 7View FIGURE 7 B, F), progressively decreasing in size and becoming rounded on chaetigers 9–10 ( Fig. 7View FIGURE 7 G). Notopodial lamellae united across dorsum, forming high dorsal crests ( Fig. 7View FIGURE 7 J) on chaetigers 7–8 (one specimen with a low fold on chaetiger 8) ( Fig. 7View FIGURE 7 B), and low dorsal folds on chaetigers 9–14 ( Fig. 7View FIGURE 7 B, J); lamellae on posterior chaetigers small, rounded ( Fig. 7View FIGURE 7 H, I). Ventral and dorsal edges of notopodial and neuropodial lamellae not touching on anterior chaetigers ( Fig. 7View FIGURE 7 C, D). Notopodial prechaetal lamellae low in branchial region, not basally fused with notopodial postchaetal lamellae ( Fig. 7View FIGURE 7 A, D, E), becoming rounder and smaller on far posterior chaetigers ( Fig. 7View FIGURE 7 I).

Neuropodial postchaetal lamellae on chaetigers 2–3 large, subtriangular, ventrally pointed ( Fig. 7View FIGURE 7 C, D), becoming rounded on chaetigers 4–5 ( Fig. 7View FIGURE 7 D, E); gradually decreasing in size on following chaetigers ( Fig. 7View FIGURE 7 F – H), smallest on far posterior chaetigers ( Fig. 7View FIGURE 7 I). Neuropodial prechaetal lamellae rounded, small in anterior region ( Fig. 7View FIGURE 7 D – F), rudimentary throughout. Interparapodial pouches lacking.

Anterior chaetae all heavily granulated and with very long capillary tips ( Fig. 7View FIGURE 7 K, L); notopodial chaetae slightly unilimbate ( Fig. 7View FIGURE 7 K), neuropodial chaetae alimbate ( Fig. 7View FIGURE 7 L); notopodial and neuropodial capillaries arranged in two rows from chaetiger 1 onwards, with short, thin chaetae, notopodial chaetae longer with the posterior row longest; chaetae from chaetiger 18 arranged in one row, chaetae thin, without granulations and with very long capillary tips ( Fig. 7View FIGURE 7 M). Neuropodia from about chaetiger 10 also arranged in one row, chaetae thin, without granulations and with very long capillary tips ( Fig. 7View FIGURE 7 N); dorsal chaetae long and ventral chaetae short; posterior notopodia with thinner and shorter chaetae than middle notopodia. Sabre chaetae in neuropodia from chaetiger 10, one per fascicle, moderately granulated and without sheaths ( Fig. 7View FIGURE 7 O). Neuropodial hooded hooks ( Fig. 7View FIGURE 7 P) from chaetigers 12–14 (holotype: 12), up to seven per fascicle, alternating with thin capillaries, posterior hooks accompanied by up to two capillaries. Notopodial hooded hooks from chaetigers 23–39 (holotype: 30) ( Fig. 7View FIGURE 7 Q) equal in length to neuropodial hooks, but slenderer and fewer per fascicle; up to four per fascicle, accompanied by up to four thin capillaries; all hooks with four pairs of small teeth above main tooth and conspicuous secondary hood ( Fig. 7View FIGURE 7 P, Q).

Pygidium with one long, thin median cirrus and two short lateral lobes ( Fig. 7View FIGURE 7 R).

Remarks. Examination of the other species in the steenstrupi  -group ( Sigvaldadóttir & Mackie, 1993: Table 2; Blake, 1996; Sigvaldadóttir 1997; Zhou & Li 2009) shows that Prionospio oligopinnulata  nov. sp. is most similar to P. depauperata Imajima 1990  and P. kulin Wilson 1990  as all three species have subtriangular, ventrally pointed neuropodial postchaetal lamellae on chaetigers 2–3 and dorsal crests on several chaetigers. However, P. oligopinnulata  differs from P. depauperata  in that in the former the prostomium is truncated anteriorly, the notopodial and neuropodial lamellae on chaetiger 1 and on the posterior parapodia are rounded, low dorsal folds are present from chaetigers 9–14, the anterior notopodial chaetae are slightly unilimbate and the neuropodial chaetae alimbate, the sabre chaetae lack sheaths, neuropodial hooded hooks are present from chaetigers 12–14 and notopodial hooded hooks from chaetigers 23–33, and all hooks have four pairs of small teeth above the main tooth. Prionospio oligopinnulata  differs from P. kulin  in that the former has a long, blunt, prominent caruncle, well developed parapodial lamellae on chaetiger 1, rounded posterior neuropodial lamellae, low dorsal folds on chaetigers 9–14, an absence of interparapodial pouches, and hooks with four pairs of small teeth above the main tooth all with a secondary hood. Prionospio oligopinnulata  also differs from P. k ul i n and P. depauperata  in that it has a slit along the middle of the caruncle. The differences between this new species and the other species examined are provided in the key and Table 1.

Etymology. The specific name is from the Greek oligo meaning few and refers to the few pinnules distributed scarcely on the branchiae.

Type locality. Gulf of Mexico Campeche, Yucatán.

UNAM

Universidad Nacional Autonoma de Mexico

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Spionida

Family

Spionidae

Genus

Prionospio