Prionospio fallax Soederstroem , 1920

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: 5

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Prionospio fallax Soederstroem , 1920


Prionospio fallax Soederstroem, 1920 

Prionospio fallax  Söderström, 1920: 235-237, figs 135, 144-145; Sigvaldadóttir and Mackie 1993: 207-211, figs 3-5, tables 1-2.

Material examined.

Atlantic Ocean, La Coruña: 1 specimen ( MNCNM 16.01/15809), A Malata, Ría de Ferrol, 43°29'30"N, 8°14'40"W, coll. J Parapar, 26 October 2000; Mediterranean Sea. Andalucia: 2 specimens ( MNCNM 16.01/8756), Punta Torrox, Malaga, 36°43'33"N, 3°57'28"W, coll. G San Martín, February 1995.


Incomplete specimens, 4.5-6.5 mm long for 39-49 chaetigers, 0.5 mm wide. Prostomium bottle-shaped, truncated anteriorly with lateral edges rounded, posteriorly tapered, with a long, blunt caruncle extending to anterior edge of chaetiger II. Two pairs of brown eyes, arranged in a trapezoid; anterior pair small, rounded; posterior pair large, reniform. Four pairs of branchiae present on chaetigers II–V; pairs 1 and 4 equal in size with sparse lateral digitiform pinnules and long naked distal tips; pairs 2 and 3 apinnate, triangular with dense lateral ciliation and sharply pointed tips; shorter than pinnate pairs. Noto- and neuropodial postchaetal lamellae smallest on chaetiger I, rounded in both rami; notopodial lamellae foliaceous, largest on chaetigers III–IV; progressively decreasing in size through chaetigers V–X, becoming rounded. Neuropodial postchaetal lamellae largest in branchial region; lamellae large, subtriangular, ventrally pointed on chaetiger II; those of chaetiger III with dorsally pointed tip; rounded on middle chaetigers, becoming rather inconspicuous on posterior chaetigers. High dorsal crest on chaetiger VII only; no crests on following chaetigers. Interparapodial pouches absent. Sabre chaetae from chaetiger X, up to two per fascicle; neuropodial hooded hooks from chaetigers XII–XIV; notopodial hooded hooks from chaetigers XL–XLIII; hooks multidentate with three to four pairs of small teeth above main tooth and secondary hood.


These specimens match the redescription given by Sigvaldadóttir and Mackie (1993), except that we found some specimens with eyes and others without eyes; one specimen had a single large brown eyespot. Possibly, the variation is due to the preservation of the specimens.


Silty (mud with much detritus) sediments, depth 25-140 m.


Northeast Atlantic, from northern Scotland (Shetland Islands) to the Mediterranean.