Iberobathynellina Camacho and Serban, 1998

Camacho, A. I., Serban, E. & Guil, N., 2000, Phylogenetical review and biogeographic remarks on the interstitial and subterranean freshwater iberobathynells (Crustacea, Syncarida, Parabathynellidae), Journal of Natural History 34 (4), pp. 563-585 : 567-574

Subtribe Iberobathynellina Camacho and Serban, 1998 Genus Guadalopebathynella Camacho and Serban, 1998

Type species: Guadalopebathynell a puchi Camacho and Serban, 1998 .

Genus diagnosis

Labrum (Lbr.): with semicircular ventral side and with eight main hook-like teeth. Thoracopod 8 (Th.8), male: outer lobe with rectangular lateral side and with posterior part longer than anterior part; exopod (Exp.) with wide lateral side and with two apical spines; dentate lobe shorter than inner lobe, with seven to eight

1. Number of segments of Antenna 1

0: 7 A, B, C, D, E, F, G, H

1: 6 I

2. Teeth of labrum (unordered character)

a: normal A, B, C, D, E, F, G, H, I

b: hook-like D

3. Thoracopod 7

0: present A, B, C, D, E, F, G, H

1: absent I

4. Number of smooth setae on segment 2 of endopod of thoracopod 1

0: 2 A, B, F

1: 1 C, G, E, G, H, I

5. Number of segments of exopod of thoracopod 6

0: 3 F, G, H

1: 2 A, B, C, D, E, I

6. Number of segments of exopod of thoracopod 7

0: 3 F, G

1: 2 A, B, C, D, E, H

2: 0 I

7. Number of smooth setae of segment 1 of exopod of thoracopod 2±5

0: 3 A

1: 2 B, C, D, E, F, G, H, I

8. Seta on segment 1 of endopod of thoracopod 2±6

0: present A

1: absent B, C, D, E, F, G, H, I

9. Number of teeth on pars incisiva of mandible

0: 6±10 A, F, G

1: 4±6 B, C, D, E, H, I

10. Number of setae on pars molaris of mandible

0: 10±16 A, G

1: 7±10 F, I

2: 5±7 B, C, D, E, H

11. Number of teeth on distal endite of maxillule 1

0: 7 A, B, F, G, H?

1: 6 C, D, E, I, H?

12. Number of spines on sympod of uropods

0: 12±27 A

1: 5±12 B, C, D, F, G, H, I

2: until 5 E

13. Cuticle of female thoracopod 8 (unordered)

a: smooth A, B, D, E, F, G, H, I

b: smooth or wrinkled C

14. Type of inner lobe of male thoracopod 8

0: with dense setae A, H

1: without setae or sparse setae B, C, D, E, F, G, I

15. Ctenidia on exopod of uropods

0: present A

1: absent B, C, D, E, F, G, H, I

16. Anal operculum of pleotelson (unordered)

0: absent A, B, D, F, G, H

1: present E, I

2: absent or present C

17. Pleopods

0: present E

1: absent A, B, C, D, F, G, H, I

teeth; inner lobe without setae at the distal end; anterior side very elongated, of similar width and length and distal rim lightly inclined from latero-outer side toward latero-inner side. Mandible (Md.): pars incisiva with ®ve to six teeth and pars molaris with seven to eight claws. Maxillule (Mx.I): distal endite with six very curved teeth. Maxillae (Mx.II): three-segmented, with a long seta on the proximal endite. Thoracopod 1±7 (Th.1±7): with exopod two-segmented. Uropod (Urp.): sympod (Symp.) with seven to eight spines; endopod (Endp.) with a long seta and exopod with four barbed setae; endp. much longer than exp. Furca (Frc.): with seven to nine spines.

Without pronounced anal operculum.

Guadalopebathynell a puchi Camacho and Serban, 1998 (®gures 1, 2)

Description

Body: total length of type male is 1.32 mm (species range n = 14: 1.1±1.33 mm), of females (n = 12) 1.25±1.63 mm. Body elongated, segments progressively widening towards posterior end of body. Head of similar length and width.

A.I (®gure 1A): with seven segments; no sexual dimorphism; length of ®rst four segments greater than that of last three, segment 5 very short; setation as in ®gure 1A (segment 5 with two aesthetascs, segments 6 and 7 with three). A.II (®gure 1B): three-segmented, last of which longest, with two smooth and one plumose terminal seta and a small, shorter seta in the middle; ®rst two segments without setae. Lbr. (®gure 1C, C¾): with eight main very curved hook-like teeth, on semicircular ventral side, and two smaller lateral teeth at either end. Md. (®gure 1D, E): pars incisiva with six (®ve to seven) well-developed teeth; pars molaris with eight teeth (seven to eight), six strong distal and two small joined proximal teeth with a large number of ®ne setae; mandibular palp does not exceed pars incisiva in length. Mx.I (®gure 1F): proximal endite with four claws (spines of diOEerent sizes); distal endite with six very curved hook-like claws concentrated from the middle towards the distal end, two smooth apical claws, the other four with spines, proximal one being smallest, and three smooth setae on outer distal margin. Mx.II (®gure 1G): three-segmented, with one long seta on basal segment; segment 2 with two long setae and one shorter at the distal end, one additional seta on inner border; segment 3 elongated with 14 setae. Th.1±7 (®gure 2A±G): seven pairs of well-developed thoracopods, length gradually increasing from pairs 1 to 5, last three pairs similar in size; well-developed epipodite on pairs 2±7, exceeding half length of basipod (Bsp.); Bsp. with one lateral, terminal seta. Th.1 (®gure 2A): short, exp. two-segmented in the ®ve completely developed specimens, immature specimens having only one segment with three setae; ®rst with two barbed setae, one ventral and one dorsal, segment 2 with two terminal setae (one plumose, the other barbed) and with two groups of ctenidia at the base of setae; endp. four-segmented: ®rst with two smooth dorsal setae, second with one smooth and one plumose seta, third with two setae, one small and smooth and the other tiny, terminal segment with two claws of diOEerent length and one seta. Th.2±7 (®gure 2B±G): exp. biarticulated, segment 1 with two terminal barbed setae, one short and one long; segment 2 with two terminal setae, one barbed, the other plumose; ctenidia at base of setae; endp. four-segmented, ®rst short and without setae; second with two groups of lateral ctenidia and one plumose and one smooth seta; third with one tiny seta; and fourth with one seta and two strong similar claws. Th.8, male (®gure 1J±M): outer lobe with rectangular lateral side and with posterior part longer than anterior part; exp. with wide lateral side and two apical spines; dentate lobe shorter than inner lobe, with seven to eight teeth upon a protuberance and hook-like; inner lobe without setae at the distal end; anterior side very elongated, of similar width and length and distal rim lightly inclined from latero-outer size toward latero-inner side. Th.8, female paratype (®gure 1I): small, rounded, with two small terminal teeth and two small teeth in the middle region. Dorsal margin of pleotelson (®gure 1N): anal operculum not pronounced; one barbed seta on lateral side. Urp. (®gure 1N): symp. almost twice the length of endp. and six/seven times longer than wide (large); with seven (six to eight) barbed spines, the most distal almost twice as long as the others which are of equal length and located from the middle towards distal end; endp. one-third longer than exp., with one inner dorsal plumose seta; exp. with two terminal barbed setae, two subterminal barbed setae of unequal length, and one plumose basiventral seta. Frc. (®gure 1N): with eight (seven to nine) similar barbed spines; two dorsal plumose setae, one large and the other shorter.

Population variation

Meristic variability occurs in the number of spines on the sympod of the uropod, on the spines on the furca, teeth on the pars molaris and the pars distalis of the mandibles and segments which form the exopod of thoracopod 1.

The exopod of the thoracopod 1 in fully mature specimens is made up of two segments; in the mandibles the pars distalis has a maximum of six teeth and the pars molaris has a maximum of eight teeth; the sympod of the uropod has a maximum of eight spines and the furca has nine.

The biggest specimens are not necessarily the most fully mature, i.e. not always those which have two segments in the exopod of the thoracopod 1. There does not exist a signi®cant correlation between the size of the specimens and the number of segments in the exopod of the thoracopod 1 (r = Õ 0.104); the greater number of spines on the sympod of the uropod (r = 0.032); and the greater number of spines on the furca (r =0.0116), there is only a slight positive correlation between the greater number of the spines on the furca and spines on the sympod of the uropod (r = 0.668).

Discussion

Guadalopebathynella is the only genus in the tribe in which the labrum and the chaetotaxie on the distal endite of the maxillula are modi®ed. Besides this, the lateral side of the external lobe of the male thoracopod 8 is between rectangular and triangular in shape whereas in the other genera it is either rectangular or triangular. We think that these characteristics justify the creation of a new genus.

Guadalopebathynella is closer to Iberobathynella than to Californibathynella . Californibathynella retains the ®rst pair of pleopods; in the other genera these do not exist and this genus is the only one in which there are ®ve teeth and two setae on the pars distalis of the maxillula. Besides, in this genus the exopod of thoracopod 1 is made up of only one segment with only two terminal setae; in the other two genera there may be one or two segments, but when there is only one it always has three setae.

Iberobathynella imuniensis Camacho, 1987 is the only species of the genus Iberobathynella with a combination of secondary characteristics similar to those of Guadalepobathynell a puchi : six teeth on the distal endite of the maxillula; similar setation on the endopod of thoracopod 1 (2/2/2/3); only one seta on the exopod of the uropod and without a pronounced anal operculum. The rest of the species of Iberobathynella (13 species) can show some of these features but never in this combination.

Subtribe Hexaiberobathynellin a Camacho and Serban, 1998