Iberobathynella (A.) cornejoensis, Camacho, 2005

Camacho, Ana Isabel, 2005, Expanding the taxonomic conundrum: Three new species of groundwater crustacean (Syncarida, Bathynellacea, Parabathynellidae) endemic to the Iberian Peninsula, Journal of Natural History 39 (21), pp. 1819-1838 : 1825-1830

Iberobathynella (A.) cornejoensis n. sp.

( Figures 3 , 4 )

Material examined

Gravel bank on the Trema stream (26 November 2003) (coordinates X: 448805, Y: 4763430, Z: 638), La Mina cave (26 April 2003) (coordinates X: 448875, Y: 4764802, Z: 673), and Redonda cave (26 April 2003) (coordinates X: 448858, Y: 4764811, Z: 668) (type locality) all of these in Cornejo (Burgos), collected by PASCALIS team (three males, one juvenile, one female and three juveniles, one female and three males, respectively). All adult specimens were studied. The holotype is a male and the type series contains 10 specimens (paratypes) ( MNCN 20.04 /5912) .

Description

Body. Total length of males 0.90–1.37 mm (holotype 1.06) and of females 1.03–1.04. Body elongated, segments progressively lengthening and widening towards posterior end of body. Head of similar length and width.

Antennule ( Figure 3A ). With seven segments; no sexual dimorphism; length of first three segments equal to length of last four; setation as in Figure 3A (segment 5 with one aesthetasc and segments 6 and 7 with three aesthetascs).

Labrum ( Figure 3B ). With eight main teeth, and two smaller lateral teeth at either end.

Mandible ( Figure 3C ). Pars incisiva with four well-developed teeth; pars molaris with five teeth, distal three with denticles, two small joined proximal teeth without denticles but with a large number of fine setae; mandibular palp does not exceed pars incisiva in length.

Maxillule ( Figure 3D ). Proximal endite with four claws (spines of different sizes); distal endite with six claws, two apical ones smooth, the other four with spines; three subterminal smooth setae on outer distal margin.

Maxilla ( Figure 3E ). Three-segmented, with one seta on basal segment; segment 2 with two long setae, and one shorter seta at the distal end, one additional seta on inner border; segment 3 elongated with 14 setae.

Thoracopods. Thoracopods 1–7 ( Figure 4A–G ): well developed, length gradually increasing from 1 to 5, 5–7 similar in size; well-developed epipodite on 2–7, exceeding half length of basipod; basipod with one lateral, smooth, terminal seta. Thoracopod 1 ( Figure 4A ): short, exopod one-segmented in all completely developed specimens, with three setae (two terminal, one seta plumose and the other barbed), and with one group of ctenidia at distal margin of the exopod; endopod four-segmented: first segment with two smooth dorsal setae, second with one smooth dorsal seta and one plumose ventral seta, third with two setae, one small and smooth, and the fourth, tiny, terminal segment with two claws of similar length and one smooth seta. Thoracopods 2–7 ( Figure 4B–G ): exopod biarticulated, segment 1 with two terminal setae, one short and smooth and one long and barbed; segment 2 with two terminal setae, one barbed, the other plumose; ctenidia at distal margin of the segments; endopod four-segmented, segment 1 short and without setae; 2 with two groups of lateral ctenidia and one plumose and one smooth seta; 3 with one tiny seta; and 4 with one seta and two strong claws of similar length. Thoracopod 8, female ( Figure 3F ): not very small, triangular and with smooth cuticle, with two teeth. Thoracopod 8, male ( Figure 3G–I ): massive, almost square; basal region massive; outer lobe almost triangular not separated from basal region; dentate lobe with 8–12 teeth; basipod rounded and with one short seta at the end, endopod small with two smooth setae of similar size; exopod small; inner lobe not fused with basipod and almost square.

Dorsal margin of pleotelson ( Figure 4H ). With anal operculum slightly pronounced, well developed; one plumose seta on lateral side.

Uropod ( Figure 4I ). Sympod almost twice length of endopod and more than three times longer than wide; with six barbed spines, the most distal longer than the others, which are of equal length and located on the front two-thirds; endopod very slightly longer than exopod, in lancet form, without setae; exopod with four barbed setae (one terminal, one subterminal, and the other two in middle of the exopod) and one small, plumose seta basiventrally.

Furca ( Figure 4H ). Solid, with five barbed spines (terminal longest); two dorsal plumose setae, one large and the other shorter.

Etymology

The species is named after the town Cornejo where it was found.

Remarks

Iberobathynella (A.) cornejoensis n. sp. belongs to the subgenus I. ( Asturibathynella ) (six teeth on distal endite of maxillule, amongst other characters). Within this subgenus it belongs to the group of species which have two setae on the endopod of segment 1 of thoracopod 1, and one seta on segment 1 of the maxilla. This group consists of the species: I. (A.) imuniensis Camacho, 1987 , I. (A.) rouchi Camacho and Coineau, 1987 and I. (A.) celiana Camacho 2003b (see Table III). In this subgroup only the species I. (A.) imuniensis has 14 setae on segment 3 of the maxilla, like the new species, while the other two species have 16 and 15, respectively.

The species I. (A.) imuniensis and I. (A.) celiana have four barbed setae on the exopod of the uropod, like the new species, but both have setae (one and three, respectively) on the endopod of the uropod, while the new species has no setae. This is the only case in the whole genus where we find this character. The new species, like I. (A.) celiana , has a slightly pronounced anal operculum but I. (A.) celiana has six segments on the antennule, while the new species has seven (which is the norm in this genus). The female thoracopod 8 in the new species is similar to that of I. (A.) imuniensis . The number of spines on the sympod of the uropod is the lowest in the subgenus: most species having more than five. There are only five spines on the furca in the new species; no other species in the subgenus has so few spines. Some of the characters exhibited by the new species are present in other species in the subgenus (see Table III), but the combination of all of them is unique to the new species. Furthermore, the absence of setae on the endopod of the uropod is a unique character, as is the presence of only five spines on the furca. From the total characters combination as well as these two characters we can say that I. (A.) cornejoensis n. sp. is without doubt a new species.

Figures

Figure 3. Iberobathynella (Asturibathynella) cornejoensis n. sp., male. (A) Antennule; (B) labrum; (C) mandible; (D) maxillule; (E) maxilla; (F) thoracopod 8 female (dorsal view); (G) thoracopod 8 male (latero-external view); (H) thoracopod 8 male (latero-internal view); (I) thoracopod 8 male (internal view). Scale bars in mm.

Figure 4. Iberobathynella (Asturibathynella) cornejoensis n. sp., male. (A) Thoracopod 1; (B) thoracopod 2; (C) thoracopod 3; (D) thoracopod 4; (E) thoracopod 5; (F) thoracopod 6; (G) thoracopod 7; (H) pleotelson and furca (dorsal view); (I) uropod (latero-internal view). Scale bar in mm.