Paraprionospio inaequibranchia ( Caullery,

Delgado-Blas, Víctor H. & Carrera-Parra, Luis F., 2018, New Phylogenetic Analysis of Paraprionospio Caullery (Polychaeta: Spionidae), with Description of a New Species from the Gulf of Mexico, Zoological Studies 57 (52), pp. 1-20 : 13-15

Paraprionospio inaequibranchia ( Caullery, 1914)

( Figs. 4 A-R)

Prionospio pinnata inaequibranchia Caullery 1914: 356-358 , fig. 2.

Paraprionospio inaequibranchia Yokoyama 2007: 267-270 , partim.

Type material: Four syntypes. Southern Africa: Siboga-Expeditie: ZMA 1568 (1), Sta. 2, Java Sea, 37 m; ZMA 1566 (1), Sta. 51, Java Sea, 69 m; ZMA 1571 (1), sta. 181, Ambon, Banda Sea, 54 m; ZMA 1688 (1), sta. 261, Banda Sea, 27 m. One of them designated as lectotype (ZMA 1688), the other are designated as paralectotypes (ZMA 1568, ZMA 1566, ZMA 1571).

Redescription: Lectotype (ZMA 1 6 8 8) incomplete specimen with 35 chaetigers, 13 mm long, 1.5 mm wide. A gravid female with ova in chaetigers 10-35. All paralectotypes incompletes with 21-35 chaetigers (11-13 mm long, 1.5-2.0 mm wide). Any variation found on paralectotypes is given in brackets. Color in alcohol yellowish-brown with no obvious patterns.

Prostomium frontally truncated to rounded, projecting slightly beyond peristomium, extending posteriorly to chaetiger 1 as a narrow caruncle ( Fig. 4A ). Eyes absent. Palps lost. Peristomium long, forming large lateral wings which enclosing completely the prostomium ( Fig. 4B ), distinct from chaetiger 1; posterior margin of peristomial wings without papillae.

Three pairs of branchiae present on chaetigers 1-3. First pair of branchiae joined basally by a prominent dorsal ridge ( Fig. 4A ); first two pairs of branchiae of similar length, the third one shortest. All branchiae with densely packed of flabellate lamellae ( Fig. 4 C-E) over most of branchial length, decreasing slightly in size distally; branchial shaft bare distal and basally; the lamellae distribution of the three pair similar as the other: first pair basally with several triangular lamellae on anterior surfaces, without anterior basal accessory lamellae; middle and distal region with flabellate lamellae enclosing lateral and posterior surfaces ( Fig. 4C ). Second ( Fig. 4D ) and third pair of branchiae basally with few triangular lamellae ( Fig. 4E ); thereafter all lamellae flabellate, continuing to the distal end. First pair of branchiae as wide as half the body width, second pair narrower, and third pair thinner, half as wide as second branchiae. Filament present at base of third pair of branchiae ( Fig. 4E ).

Anterior notopodial postchaetal lamellae well developed, triangular ( Fig. 4B ), basally wider and rounded, distally pointed on chaetigers 1-6 ( Fig. 4 F-I); longest over chaetigers 2-4 ( Fig. 4B ); oval and smaller on chaetigers 7-9 ( Fig. 4 J-L), posteriorly becoming subtriangular at least until chaetiger 13 ( Fig. 4M ), from posterior chaetigers rounded, smallest. Dorsum of chaetigers 13- 17 with transverse series of three slightly raised ridges. Dorsal crests on chaetigers 21-26 (two paralectotypes with dorsal crest missing). Ventral and dorsal edges of notopodial and neuropodial lamellae touching on chaetigers 1-2 ( Fig. 4 F- G). Notopodial prechaetal lamellae very large in anterior chaetigers ( Fig. 4B ), basal and middle edges fused with notopodial postchaetal lamellae ( Fig. 4B , G-I), with fold or cup-shaped appearance becoming more pronounced on more anterior chaetigers when lamellae increase its size, with dorsolateral edge becoming more curved ( Fig. 4 G- I).

Neuropodial postchaetal lamella triangular on chaetiger 1 ( Fig. 4F ), triangular on chaetiger 2 ( Fig. 4G ), becoming wider and rounded with a small central projection on chaetiger 3 ( Fig. 4H ), rounded on chaetigers 4-9 ( Fig. 4 I-L), diminishing progressively in size to chaetiger 9; thereafter becoming a small triangular lobe ( Fig. 4M ). Neuropodial prechaetal lamellae very small ( Fig. 4B , F-I), rudimentary throughout. Interparapodial pouches on chaetigers 9-19 (paralectotypes on chaetigers 11/17-18/28). Ventral crest absent on chaetiger 8.

Chaetae of first five chaetigers arranged in three rows, thereafter arranged in two rows, with chaetae of posterior row longest. All notopodial chaetae unilimbate, smooth ( Fig. 4N ), larger than those of neuropodia. Anterior neuropodial chaetae smooth, weakly bilimbate, anterior row broadest, ( Fig. 4O ), and shorter than those of posterior row. Sabre chaetae from chaetiger 9, with up to three per neuropodium, each chaeta stout, strongly granulated, without limbation ( Fig. 4P ). Neuropodial hooded hooks ( Fig. 4Q ) from chaetiger 9, with up to 15 per neuropodium, alternating with long, slender, alimbate chaetae. Notopodial hooded hooks ( Fig. 4R ) from chaetiger 30 (paralectotypes on 30-33), with up to three per notopodium, alternating with long and thin capillary chaetae. All hooded hooks, with three pairs of apical teeth above main fang and striated secondary hood ( Fig. 4 Q-R); with long, slightly curved shaft.

Posterior segments missing from all specimens.

Distribution: Herein, we restring the distribution of this species to the region of the Banda Sea and Java Sea.

Remarks: Prionospio pinnata inaequibranchia was described by Caullery (1914) based on specimens collected off Southern Africa from 54 to 1000 m depth. Recently, Yokoyama (2007) redescribed Paraprionospio inaequibranchia based on the syntypes and a specimen from Gadavari estuary, India, reported as P. lamellibranchia by Hartman (1974) and specimens collected from Malaysia. Yokoyama (2007) noted that the shape of the notopodial postchaetal lamellae is elongate, subtriangular on chaetigers 1-3, becoming low rounded and shorter from chaetiger 4 to about chaetiger 11. However, Yokoyama did not provide details on the notopodial lamellae which are anteriorly curved or folded, tapering dorsally with a gently curving at the dorsolateral border. The fold or cup-shaped appearance becomes more pronounced on more anterior chaetigers when the lamella is larger, with the dorsolateral edge becoming more curved. This cup result from the fusion of the medial edges of the pre- and postchaetal lamellae rather than folds in the postchaetal lamellae. Also, Yokoyama (2007) reported two pairs of dark-brown eyes in trapezoidal arrangement, neuropodial hooks with 4-5 pairs of accessory teeth, and notopodial hooks with 4 pairs. However, the presences of these eyes and the number of the apical teeth are based on the specimens from Malaysia and India. None of the type specimens have eyes and all noto- and neuropodial hooks have three pairs of accessory teeth. We do not consider the specimens from Malaysia and India as belonging to Paraprionospio inaequibranchia .

Figures

Fig. 4. Paraprionospio inaequibranchia (Caullery, 1914). Lectotype ZMA1688. (A) anterior region, dorsal view; (B) anterior region, dorso-lateral view; Paralectotype ZMA1568. (C) first branchia; (D) second branchia; (E) third branchia and filament; (F) parapodium of chaetiger 1; (G-I) parapodium of chaetigers 2-4; (J-L) parapodium of chaetigers 7-9; (M) parapodium of chaetiger 13; (N) capillary notochaeta, chaetiger 2; (O) capillary neurochaeta, anterior chaetiger; (P) sabre chaeta, chaetiger 10; (Q) neuropodial hooded hook, chaetiger 11; (R) notopodial hooded hook, chaetiger 34. Scale bars: A-I = 571.2 µm; J-L = 571 µm; M = 200 µm; N-R = 50 µm.