Parvipalpus onubensis, a new species (Crustacea: Amphipoda: Caprellidea) from the Atlantic coast of Southern Spain*

An annual research programme on sediment communities from the coast of Andalucía (Southern Spain) was initiated during July-September 2000. The project, supported by the Environmental Agency of the Andalusian Government, is focused on the environmental control of the littoral zone based on the macrofaunal communities and their relationships with the abiotic variables. As a first result of this research program, several specimens of the genus Parvipalpus were found on the coast of Huelva (Atlantic coast of Southern Spain). A detailed examination revealed that these specimens belong to a new species, here-by described as Parvipalpus onubensis. More than 25 species of the Caprellidea have been collected along the Iberian Peninsula (unpublished data). Only five of these species have been reported from soft bottoms (Caprella acanthifera Leach, 1814; Pariambus typicus Kröyer, 1814; Phtisica marina Slabber, 1769; Pseudolirius kröyeri (Haller, 1897) and Pseudoprotella phasma (Montagu, 1804)). Furthermore, two new species, Caprella pseudorapax and C. sabulensis, have been recently described from sediments collected at the coastline AlgecirasTarifa and Ceuta on the Mediterranean Coast of the Strait of Gibraltar (Guerra-García et al., in press.). The type specimens (holotype, allotype and some paratypes) have been deposited in the Museo Nacional de Ciencias Naturales de Madrid, Spain (MNCN 20.04/5310). SCI. MAR., 65 (4): 333-339 SCIENTIA MARINA 2001


INTRODUCTION
An annual research programme on sediment communities from the coast of Andalucía (Southern Spain) was initiated during July-September 2000.The project, supported by the Environmental Agency of the Andalusian Government, is focused on the environmental control of the littoral zone based on the macrofaunal communities and their relationships with the abiotic variables.
As a first result of this research program, several specimens of the genus Parvipalpus were found on the coast of Huelva (Atlantic coast of Southern Spain).A detailed examination revealed that these specimens belong to a new species, here-by described as Parvipalpus onubensis.
The type specimens (holotype, allotype and some paratypes) have been deposited in the Museo Nacional de Ciencias Naturales de Madrid, Spain (MNCN 20.04/5310).

MATERIAL AND METHODS
Benthic sediment samples were collected with a Van Veen grab (0.05 m 2 ).The samples were sieved through a 0.5 mm mesh and the infauna was preserved in 5% buffered-formalin containing Rose Bengal solution to ease sorting.Granulometry of the sediment was determined by Buchanan and Kain's method (Buchanan and Kain, 1984).Sediment organic matter (%) was analysed by ashing to 500ºC (mean value for three replicates per sample).For microscopical study, caprellid specimens were dissected under a stereomicroscope.Permanent mounts were made in polyvinyl lactophenol.All figures were drawn with the aid of a camera lucida.ceding 2 articles together; propodus twice as long as width, palm convex, serriform, with a pair of grasping spines near proximal end; dactylus provided with long, acute denticules.Gnathopod 2 inserted in the anterior half of pereonite 2; basis ca.3/4 of pereonite 2 in length; carpus short, ca.1/3 of merus in length; ischium cylindrical; palm of propodus scarcely setose, provided with a proximal tooth located in a round prominence.

Family
Penes located medially, well developed and curved at the middle, length ca. 3 times width.Abdomen without appendages; a single dorsal lobe with 2 large plumose setae.
Pereopods are missing in holotype.Mouthparts and pereopods are, therefore, described from a paratype (female).
Pereopods 5-7 increasing in length respectively; palm of propodus without grasping spines; dactylus carrying a long plumose seta on proximal end.
Mouthparts: Upper lip symmetrically bilobed, pubescent apically.Inner lobes of the lower lip almost fused; outer lobes finely setose on distal part.Inner lobe of the maxilliped rectangular and distally expanded, carrying a row of plumose setae and a tooth; outer lobe, twice as long as inner one, provided with 4 teeth and 5 simple setae; palp 4-articulate, articles 2 and 3 setose.Mandibular palp 2-articulate, carrying a strong seta distally; incisor and lacinia mobilis 4-toothed; a row of 3 plumose setae on left mandible and 2 on the right one; molar well developed; molar flake, present in the right mandible, rounded.Maxilla 1 outer lobe with 6 forked teeth distally; palp 2-articulate, the distal one with 4 teeth setae and 3 spiniform teeth; a row of 4 setae on lat-eral face.Maxilla 2 inner and outer lobes oval, carrying simple setae on end; outer lobe a little longer than inner lobe.
Allotype female, 2.33 mm in length.Flagellum of antenna 1 with 3 articles.Oostegite 3 setose on anterior margin.Gnathopod 1 and 2 similar to those in male.
Etymology: The specific name onubensis refers to "Onuba" the roman name of Huelva, the type locality.

Intraspecific morphological variation:
The number of articles in the flagellum of antenna 1 is a constant character in all mature males (5) and females (3) studied.
Carausu (1941) described Parvipalpus major on the basis of the specimens collected from the 338 J.M. GUERRA-GARCÍA et al.Mediterranean coast of France and Monaco.This species, considered traditionally as a Mediterranean endemism (Krapp-Schickel, 1993) had not been reported since its original description until Laubitz and Sorbe (1996) collected it in deep-water samples from the Southern Bay of Biscay (Atlantic Ocean) and redescribed the species.The four species of Parvipalpus described so far (P.capillaceus, P. linea, P. major and P. onubensis) are compared in Table 1.Parvipalpus onubensis differs from the remaining species mainly in the body length, in the number of flagellar articles of antenna 1, in the incisor and lacinia mobilis and the penes.
The specimens of P. onubensis were collected in gross sand (according to Buchanan and Kain (1984)) with abundant biodetritic remains and low values of the organic matter (lower than 2%).The crustacean community of the bottoms where the new species was found was dominated by the gammaridean amphipods Ampelisca sp, Dexamine spinosa (Montagu, 1813), Harpinia sp, Melita palmata (Montagu, 1804), Photis longipes (Della Valle, 1893) and Pontocrates arenarius (Bate, 1858) and the decapods Callianassa sp and Liocarcinus sp.Another two caprellid species were found living together with P. onubensis: Phtisica marina Slabber, 1769 and the recently described Caprella sabulensis Guerra- García et al. (in press), which extends its distribution to the Atlantic Ocean with the present paper.