Prionospio gabriellae, Delgado-Blas & Fonseca-González, 2023

Delgado-Blas, Víctor H. & Fonseca-González, Idalyd, 2023, Two new species of spionids from the genera Apoprionospio Foster, 1969 and Prionospio Malmgren, 1867 (Annelida: Spionidae) from the Colombian Caribbean, Zootaxa 5256 (2), pp. 158-172 : 167-169

Prionospio gabriellae sp. nov.

Figures 4A–I ; 5A–E

Material examined: Caribbean Sea: Sanguaré Natural Reserve, Gulf of Morrosquillo , Sucre (09°42′30.6″N, 75º41´29.0″W), in Thalassia testudinum seaweeds, holotype ( CEMUA: ANNE: 002066 ); Sixty-seven paratypes ( CEMUA: ANNE: 002282 ), colls. Delgado-Blas, VH., Fonseca-González, I., and Londoño-Mesa, MH., June 12 th 2019 .

Description: Holotype complete, 14.3 mm long for 71 chaetigers, 0.45 mm wide. Color in alcohol opaque white. 8 Paratypes complete 4.3–5.7 mm long, 0.25–0.3 mm wide, with 59–69 chaetigers. 59 Paratypes incomplete 2.4–7.2 mm long, 0.25–0.4 mm wide, with 19–41 chaetigers. Prostomium subtriangular, rounded on anterior margin, with a small medial peak in the dorsal region, tapered posteriorly, with blunt caruncle extending to the posterior edge of chaetiger 2 ( Figs 4A , 5A ), with large triangular nuchal organs on either side. Two pairs of subdermal black eyes, arranged in a trapezoid; the anterior pair, crescent to rounde in shape ( Fig. 5B ); the posterior pair, oval and very large ( Figs 4A , 5A ). Almost all specimens with palps missing, except one specimen with a pair of long palps with heavily scalloped ridges and ciliated groove, without basal sheaths ( Fig. 4B ), and some ones with regenerated palps ( Fig. 4C ). Peristomium small, collar-shaped, surrounding the prostomium, fused dorsally with very large rounded notopodial lamellae of chaetiger 1 ( Figs 4C , 5C ). Neuropodial postchaetal lamellae of chaetiger 1 rounded and very small ( Fig. 4C ), much smaller than 1/3 the size of the notopodial lamella.

Five pairs of long, thick branchiae present on chaetigers 2–6: first and fifth pairs longest, generally first pair longer than fifth ( Figs 4C , 5B ). All branchiae with thick, tapered tips ( Fig. 4C ). Pairs 1, 4, and 5 with long, dense digitiform pinnules on the posterior face, and long, naked, smooth, distal tips ( Figs 4A , A’, 5B). Pairs 2 and 3 cirriform, with sparsely lateral ciliation and blunt tips ( Fig. 4C, D ); equal in size, shorter than pinnate pairs, but larger than notopodial lamellae ( Fig. 4C ).

Notopodial postchaetal lamellae foliaceous and wider on chaetigers 2–6 ( Figs 4C, D , 5C ), lamellae shorter and subtriangular on chaetiger 2, largest on chaetigers 4–6, with blunt tips ( Fig. 4C, D ); lamellae of chaetigers 7–8 subtriangular, subsequent notopodial lamellae round ( Fig. 5C, D ), and small on far posterior chaetigers. Chaetigers 2–4 overlapping the ventral and dorsal edges of the noto- and neuropodial lamellae. Notopodial prechaetal lamellae very large in the branchial region, basally fused with notopodial postchaetal lamellae ( Figs 4C , 5C ), progressively decreasing in size after chaetiger 8, on posterior chaetigers rudimentary. Very low dorsal ridges across the dorsum ( Fig. 4E ) on chaetigers 8–29, highest on chaetigers 16–25.

Neuropodial postchaetal lamellae square on chaetiger 2 ( Fig. 4C ); all neuropodial lamellae rounded, biggest on chaetiger 3 ( Figs 4C , 5C ), and small on far posterior chaetigers. Prechaetal lamellae very small ( Fig. 4C ), rudimentary throughout. Inter-parapodial pouches lacking.

Anterior chaetae all capillaries limbate, thin, with long capillary tips ( Fig. 4D ); anterior row with chaetae slightly granulated and posterior row striated and lacking granulations ( Fig. 4F ); notopodial and neuropodial capillaries of chaetiger 1 arranged in one rows, with short and thin chaetae, notopodial chaetae longer; from chaetiger 2 onwards arranged in two rows, anterior row shorter than posterior row; chaetae on middle and posterior notopodia arranged in one row, dorsal chaetae very long and ventral chaetae short. Sabre chaetae in neuropodia from chaetigers 12–13 (one specimen in chaetiger 12), one or two per fascicle, robust, very long, moderate granulated, with long tips but no sheaths ( Fig. 4G ). Neuropodial hooded hooks from chaetigers 13–14, up to eight (5–8) per fascicle, accompanied by up to three capillaries (chaetiger 38) ( Fig. 4G ). Notopodial hooded hooks from chaetigers 29–43, up to 2 per fascicle, accompanied by capillaries ( Fig. 4H ); all hooks with four pairs of small teeth above the main tooth and a small secondary hood ( Fig. 4G, H ). Neuropodial hooks with a small principal hood, and notopodial hooks with large hoods.

Pygidium with one long dorso-medial cirrus and two short lateral lobes ( Figs 4I , 5E ).

Etymology. The name of the species is dedicated to the daughter of the second author Gabriela Colorado Fonseca, a sweet young woman, sensitive to nature, who enjoys painting and loves the sea, and is already a little guardian of marine life.

Type locality. Caribbean Sea , Sanguaré Natural Reserve, Sucre, Colombia .

Remarks: Prionospio gabriellae sp. nov. is distinguished from all other Prionospio species with five branchial pairs by having dorsal crests across the dorsum on chaetigers 16–25. Closely related species are P. heterobranchia Moore, 1907 and P. caribensis Delgado-Blas, 2014 all sharing the following characters with Prionospio gabriellae sp. nov.: dorsal folds on several postbranchial chaetigers, very large notopodial prechaetal lamellae fused with the notopodial postchaetal lamellae, neuropodial postchaetal lamellae of chaetigers 4 and 5 rounded and neuropodial hooded hooks with 4 pairs of teeth.

Prionospio gabriellae sp. nov. differs from P. heterobranchia and P. caribensis in that the former has a small medial peak in the dorsal region of prostomium, the first neuropodial lamellae is very small, the shaped of branchial pairs 2 and 3 are cirriform, neuropodial postchaetal lamellae of chaetiger 2 is square, all chaetae of chaetiger 1 are arranged in a row. In addition, P. gabriellae sp. nov. differs from P. heterobranchia in that the former has very low anterior neuropodial prechaetal lamellae.Also, P. gabriellae sp. nov. differs from P. caribensis in that the former has a small peristomium, all the anterior chaetae with granulations and striated, the sabre chaetae appear from chaetigers 12–13, and sabre chaetae are less granulated, and the pygidium having two lateral lobes.

Figures

FIGURE 4. Prionospio gabriellae sp. nov. holotype (CEMUA: ANNE:002066: A. Anterior region, dorsal view. A’. Branchiae structure. Paratype (CEMUA: ANNE:002282): B. Palp. C. Anterior region, lateral view. D. Parapodium and branchiae from chaetigers 3–4. E. Dorsal ridges and notopodial postchaetal lamellae from chaetigers 16–18, F. Notopodial chaeta from anterior chaetigers. G. Parapodium and chaetae from chaetiger 14. H. Notopodial hooded hooks. I. Posterior region and pygidium, ventral view. nopl: Notopodial prechaetal lamellae. Scale bars: a–e, 12.5 µm; a’, f–h, i, 5 µm.

FIGURE 5. Prionospio gabriellae sp. nov. Paratype (CEMUA: ANNE:002282): A. Anterior region, dorsal view. B. Anterior region, right lateral view. C. Anterior region left lateral view. D. Middle region, ventral view. E. Posterior region and pygidium, ventral-lateral view. Scale bars: a, c, 62.5 µm; b, 37.5 µm; d, 31.3 µm; e, 42.5 µm.