Pseudopolydora multispinosa, Radashevsky & Malyar & Pankova, 2021

Radashevsky, Vasily I., Al-Kandari, Manal, Malyar, Vasily V. & Pankova, Victoria V., 2021, Pseudopolydora (Annelida: Spionidae) from the Arabian Gulf, Kuwait, European Journal of Taxonomy 773 (1), pp. 120-168 : 156-159

Pseudopolydora multispinosa sp. nov.

urn:lsid:zoobank.org:act:6079E358-FCE7-444E-861D-7B3D7FE93A4F

Figs 1D , 20–21

Pseudopolydora cf. corniculata – Al-Kandari et al. 2019: 9. — Not Radashevsky & Hsieh 2000.

Diagnosis

Prostomium with two long, pointed fronto-lateral extensions. Caruncle to end of chaetiger 6. Occipital antenna long, cirriform. Chaetiger 5 with numerous spines in notopodia – up to 32 in the anterior row and 27 in the posterior row, and well developed notopodial postchaetal lamellae. Branchiae posteriorly present beyond the middle of the body. Formalin-fixed specimens intensely stained with MG on the ventral side of body from chaetiger 8 onwards.

Etymology

The species name refers to the large number of heavy spines in the notopodia of chaetiger 5.

Material examined

Holotype KUWAIT • 1spec.; Arabian Gulf, Al-Salmiya, cove near Lebanese Restaurant ; 29.32778° N, 48.09299° E; 5 Mar. 2015; Vasily I. Radashevsky leg.; middle intertidal; fine sand; MIMB 40906 .

Description

Holotype

About 10 mm long, 1 mm wide for about 40 chaetigers with small regenerating posterior chaetigers and pygidium. Pigmentation absent on palps and body. Prostomium anteriorly bifurcated, with two long, pointed fronto-lateral processes (left process broken) ( Fig. 20D–E ), posteriorly extending to end of chaetiger 6 as a low caruncle ( Fig. 20B–C ). Long cirriform occipital antenna present on caruncle between palps. Two pairs of black eyes arranged trapezoidally. In life, palps longer than body, flexible, with frontal longitudinal groove lined with fine cilia, and short compound non-motile cilia arising directly from palp surface arranged on sides of groove and sparsely scattered on lateral and abfrontal palp surfaces.

Chaetiger1well separated from peristomium,with short winged capillaries in neuropodia and well developed cirriform noto- and neuropodial postchaetal lamellae; notochaetae absent. Chaetiger 2 notochaetae all slender capillaries with narrow limbation. Anterior-row notopodial capillaries on chaetiger 3 with slightly enlarged wing; capillaries on chaetiger 4with wing slightly wider than on chaetigers 3, intermediate between those on chaetigers 3 and 5. Anterior-row capillaries on chaetigers 3, 4, 6 and 7 arranged in J-shaped series; posterior-row capillaries on these chaetigers arranged in vertical series ( Fig. 20A ). Posterior notopodia with a few long alimbate capillaries arising from elongated fleshy notopodial lobes. Posterior neuropodial lobes also elongated and fleshy, each with a series of hooks on top.

Chaetiger 5 as same in size as chaetigers 4 and 6, with dorsal superior capillaries, two kinds of dorsal spines arranged in a double U-shaped row, and ventral capillaries; postchaetal lamellae well developed in both rami, same as on chaetigers 4 and 6 ( Figs 20A–B , 21A ). Dorsal superior and ventral capillaries similar in size, number and arrangement to those on chaetigers 4 and 6 ( Fig. 21A ). Outer (anteriorrow) notopodial spines with distal part of stem curved, gradually narrowing, with wide, distally pointed limbation ( Fig. 21B–C ), 32 in a series. Inner (posterior-row) notopodial spines simple falcate ( Fig. 21B– C ), 27 in a series. Posterior upper part of U-shaped series of spines at same level as anterior upper part. Newly developed spines in posterior upper part of U-shaped series slightly larger than older spines in anterior upper part of series.

Hooks in neuropodia from chaetiger 8, up to 30 in a series, not accompanied by capillaries. Hooks bidentate, with upper tooth closely applied to main fang; shaft with constriction on upper part and lower part bent at right angle ( Fig. 21D–E ).

Branchiae from chaetiger 7 to chaetiger 29, flattened, with surfaces oriented perpendicular to body axis, free from notopodial postchaetal lamellae.

Nototrochs from chaetiger 5 onwards, composed of single rows of cilia. On branchiate chaetigers, nototroch cilia long, arranged in transverse lines and extending onto branchiae; on posterior abranchiate chaetigers, cilia arranged in U-shaped bands, with arms directed posteriorly. Nototrochs on chaetigers 5 and 6 interrupted in the middle by caruncle; nototrochs on succeeding chaetigers complete. Intersegmental ciliation absent.

Pygidium bilobed, with two semi-oval lateral lobes, white due to numerous spindle-shaped glandular cells with striated contents.

Glandular pouches in neuropodia from chaetiger 1, largest and paired in chaetigers 6 and 7, single in other neuropodia.

Digestive tract without gizzard-like structure and pigmentation.

Nephridia from chaetiger 4 onwards, very narrow in chaetigers 4–6, prominent, greenish from chaetiger 7, in female fertile chaetigers opening to exterior via single middorsal nephridiopore.

MG staining

Weakly stained prostomium, caruncle, dorsal side of peristomium and ventral side of seven anterior chaetigers. Intensely stained ventral side from chaetiger 8 ( Fig. 20A, E–F ). As usual for other species, pale greenish staining on the anterior chaetigers and on the dorsum disappeared soon after placing the specimen into clean ethanol; intense violet staining on the ventral side from chaetiger 8, on the contrary, remained for hours ( Fig. 20F ).

Habitat

The only individual of P. multispinosa sp. nov. was found in a silty tube in a muddy sand intertidal habitat.

Reproduction

Pseudopolydora multispinosa sp. nov. is probably gonochoristic. The holotype is a female without oocytes but with glandular cells in the wall of the distal part of enlarged nephridia typical for female fertile chaetigers in Pseudopolydora worms. The enlarged nephridia open to the exterior via single middorsal nephridiopore, appearing first on chaetiger 13. The oocytes may thus develop from chaetiger 12 onwards.

Remarks

Pseudopolydora multispinosa sp. nov. is unusual among Pseudopolydora in having numerous spines in the notopodia of chaetiger 5 (up to 32 in the anterior row and 27 in the posterior row), well developed notopodial postchaetal lamellae on chaetiger 5 (as same as on chaetigers 4 and 6), and branchiae posteriorly arranged beyond the middle of the body. The majority of Pseudopolydora adults have notopodial postchaetal lamellae on chaetiger 5 totally lacking or greatly reduced, and branchiae limited to the anterior half of body. The only known individual of P. multispinosa sp. nov. has a unique pattern of MG staining: an intensely stained ventral side of the body from chaetiger 8 onwards, which remained for hours after placing the specimen into clean ethanol.

Pseudopolydora multispinosa sp. nov. appears similar to P. corniculata Radashevsky & Hsieh, 2000 from Taiwan described by Radashevsky & Hsieh (2000). They have prostomia with long pointed frontolateral horns, caruncles extending beyond chaetiger 5, chaetiger 1 with long cirri-form postchaetal lamellae in both rami, chaetiger 5 with postchaetal lamellae well developed in both rami, notopodial spines of chaetiger 5 of similar morphology, and bilobed pygidia. Pseudopolydora multispinosa sp. nov. differs, however, by the large number of spines in the notopodia of chaetiger 5.

Distribution

Arabian Gulf: Kuwait ( Fig. 1D ).

Figures

Fig. 1. Maps showing records (yellow circles) and type localities (stars) of Pseudopolydora spp. from the Arabian Gulf, Kuwait (see Supp. Table ESM1). A. P. antennata (Claparède, 1868). B. P. arabica Radashevsky & Al-Kandari, 2020 (red star = type locality: Al-Salmiya, Kuwait). C. P. kuwaiti sp. nov. (red star = type locality: Al-Judailiat). D. Yellow star = type locality of Pseudopolydora auha sp. nov.: Auha Is.; red star = type locality of P. melanopalpa sp. nov.: Sulaibikhat Bay; green star = type locality of Pseudopolydora multispinosa sp. nov.: Al-Salmiya, Kuwait.

Fig. 20. Adult morphology of Pseudopolydora multispinosa sp. nov., holotype (MIMB 40906, formalinfixed and stained with MG). A–C. Anterior end, left lateral (A) and dorsal (B–C) view. D–F. Anterior end, ventral view, showing changing of MG staining in time after return of the specimen to clean ethanol: after 1 minute (D), after 15 minutes (E), after 1 hour (F). Abbreviations: ch5 = chaetiger 5; la = lateral peristomial lip; ve = ventral peristomial lip. Scale bars = 200 µm.

Fig. 21. Chaetal morphology of Pseudopolydora multispinosa sp. nov., holotype (MIMB 40906, formalin-fixed and stained with MG). A. Parapodia of chaetiger 5.B–C. Notopodial spines of chaetiger 5. D. Neuropodium of chaetiger 12, showing glandular cells intensely stained with MG around a series of hooded hooks. E. Hooded hooks from neuropodium of chaetiger 12. Abbreviations: arrow showing the direction towards the inside of the U-shaped row of spines; no = notopodial postchaetal lamella; su = dorsal superior capillary chaetae; ve = ventral capillary chaetae. Scale bars: A = 50 µm; B–E = 20 µm.