ONE MORE PIECE IN THE GENUS PUZZLE : A NEW SPECIES OF IBEROBATHYNELLA SCHMINKE , 1973 ( SYNCARIDA , BATHYNELLACEA , PARABATHYNELLIDAE ) FROM THE IBERIAN PENINSULA

A new Iberian species of the genus Iberobathynella is described from the groundwater of Ojo Guareña cave, in the north of Spain (Burgos). The new species belongs to the subgenus Espanobathynella and presents a unique combination of characters, as follow: female thoracopod 8 with wrinkled cuticle and 1 tooth (the rest of species in this subgenus show a smooth cuticle); seven-eight spines on the furca; 10-12 spines on the sympod, four barbed setae on the exopod and an unarmed endopod of the uropod; labrum with 9 main teeth in the female and 8 in the male; maxilla with one, four and 15 setae on its three segments, respectively; seven teeth on the distal segment of the maxillule; seven teeth on the pars incisiva and seven-nine teeth on the pars molaris of the mandible and antennule with 7 segments.


Introduction
With the discovery of one more new species, the tribe Iberobathynellini (Camacho and Serban, 1998) now comprises 26 species in the Iberian Peninsula and four in the rest of the world (three in North America and one in North Africa).This makes it the most diverse and studied group of the family Parabathynellidae (Crustacea, Syncarida, Bathynellacea) (Camacho & Serban, 2000;Camacho, 2003bCamacho, , c, 2005)).
Of the 20 species of iberobathynellids known to date, none shows the combination of characters present in the new species described here.The new species belongs to the genus Iberobathynella Schminke, 1973 (with 21 species) (see table 1), and to the subgenus Espanobathynella Camacho et Serban, 1998 (with four species).This is the first time that this subgenus has been found in Burgos, and the especies has been named I. (E.) burgalensis n.sp.for that reason.This subgenus is the least diversified of the genus since it includes only three species, with a very limited distribution, known from the Eastern part of Asturias (Picos de Europa) and the Sierra de la Collada (Asturias and Cantabria).The other subgenus present in this area, Asturibathynella, comprises 11 species showing a broader distribution.
This discovery is also relevant for the investigation of the group from a phylogenetic point of view.Some of these new combinations of characters give continuity to the range of currently known character series and fill in gaps which will be very useful in resolving relationships between species (Camacho et al., 1997(Camacho et al., , 2000;;Guil & Camacho, 2001).

Methods
The specimens studied occurred in one sample obtained from Burgos, North of Spain.
The material was collected with a 0.1 mm mesh hand net (plankton type) from water in a small pool in a cave.All specimens comprising the type series were completely dissected, and kept as permanent preparations (special metal slides, glycerine gelatine stained with methylene blue as mounting medium).Anatomical examinations were performed using an oil immersion lens (100X).The descriptions are based on the type series.The material is deposited in the Museo Nacional de Ciencias Naturales, Madrid (MNCN).
VARIABILITY.The female is similar to the male, except for the thoracopod 8 and the number of main teeth of the labrum (Fig. 5C), nine in all females studied and eight in all males.The variability affects: the number of teeth on the pars incisiva of the Md.(the specimens studied have between seven and nine teeth); the number of spines on the sympod of the uropod (10 to 12); and the number of spines on the furca (6 to 8).The holotype (male) is the only specimen studied that has a small dorsal seta on segment 1 of the endopod of the Th. 5 (in the other legs this segment has a small dorsal spine).In the other specimens all legs (except the Th. 1) have a small dorsal spine on the first segment of the endopod.
The species of subgenus Iberobathynella (Iberobathynella) Schminke, 1973 have a seta on the first segment of the endopod of Th. 2 to 7. The other species of genus Iberobathynella do not have it.
ETYMOLOGY.The species name is derived from the province of Burgos, in the North of Spain which is full of caves and where many different species of Bathynellacea have been found.
REMARKS.The new species belongs to the subgenus I. (Espanobathynella) Camacho et Serban, 1998 (see Table 2).It has seven teeth on the distal endite of the maxillule combined with: one seta on segment one of the Mx.II; 2 setae on segment one and three setae on segment 2 of the endopod of the Th.1; no seta developed on segment one of the endopodod of Ths. 2 to 7; and the external lobe of Th 8 male has the sloping main axis.There are three generic characters that have to be modified in the diagnosis (Camacho et Serban, 1998) due to the incorporation of the new species: pars incisiva of the Md with 4 to 7 teeth, pars molaris with 6 to 9 teeth and endopod of the uropod with 1 or 0 setae.2) have a female Th. 8 with a wrinkled cuticle like the new species.Other characters shared between the new species and other members of the subgenus are summarized in table 2. For example, the absence of setae on the endopod of the uropod (shared with I. (A.) cornejoensis Camacho, 2005).But members of the subgenus never have seven teeth on the distal endite of the Mx.I as do the species of the subgenus Espanobathynella and Iberobathynella (Camacho et Serban, 1998).
The new species is easily recognised based on the combination of carácter states shown in table  2. In addition, the overall appearance and size of the different lobes of the male thoracopod 8, are also diagnostic.

Distribution
Figure 6 shows the distribution of the new species and also the distribution of the rest of species in the subgenus Espanobathynella found in the North of the Iberian Peninsula.
The new species of Iberobathynella was found in Burgos where no other species of the subgenus Espanobathynella occur (Camacho, 2003c).To date, 21 species of this endemic genus are known on the Iberian Peninsula.Mainly concentrated in the north and west; in the south and east they are known from two localities only.
The subgenus Espanobathynella is restricted to a small part of Cantabria and Asturias (Eastern part of Asturias, Picos de Europa and the Sierra de la Collada, between Asturias and Cantabria) (see Fig. 6).I. (E.) espaniensis inhabits only the type locality, Cueva del Infierno (Covadonga, Asturias) whereas I. (E.) magna shares the same type locality and also occupies numerous caves in the Sierra de la Collada (Asturias and Cantabria).I. (E.) cantabriensis dwells in several caves of the Sierra de la Collada.The new species lives in the Ojo Guareña cave, where the species I. (A.) guarenensis is also found, but in different parts of this vast cave system.Another species, I. (A.) cornejoensis, is found in another cave connected to the main cave and in the interstitial environment of the river Trema (Cornejo) that flows over the Ojo Guareña system.
Serban et Comas, 1978as nine main teeth on the labrum, like the females of the new species.In addition, both have the same number of teeth on the pars molaris of the Md.But I. (E.) burgalensis n.sp has more teeth on the pars distalis of the Md.than any other species in the genus, and less setae on the third segment of the MxII (15 only).The new species has 2 segments on the exopod of the first thoracopod, as I. (E.) magna and I. (E.) espaniensisSerban et Comas, 1978.But I. (E.) burgalensis n.sp shows four unique characters in the subgenus: absence of basal seta on the exopod of uropod; absence of seta on the endopod of uropod, wrinkled cuticle in the female Th. 8, and only one spine on the latter Th.Several species of the subgenus Asturibathynella Camacho etSerban, 1998 (viz.I. (A.)asturiensis Serban et Comas, 1978; I. (A.) parasturiensis Camacho et Serban, 1998; I. (A.) rouchi Camacho & Coineau, 1987; I. (A.) guarenensis Camacho, 2003b and I. (A.) lamasonensis Camacho, 2005) (table ber