Torrenticola limula Gerecke & Di Sabatino, 1996

Sabatino, Antonio Di, Gerecke, Reinhard, Gledhill, Terence & Smit, Harry, 2009, On the taxonomy of water mites (Acari: Hydrachnidia) described from the Palaearctic, part 2: Hydryphantoidea and Lebertioidea, Zootaxa 2266, pp. 1-34 : 26-27

Torrenticola limula Gerecke & Di Sabatino, 1996

Torrenticola anomala Gil, 1990 nec Koch, 1837

Material examined: Spain, coll. Gil, Pyrenees, Lerida: Villanova de Meiá, fuente Blanca, 31TCG371551, 1000 m, 25.02.1986 (3/5/0); Villanova de Meiá, fuente del Regué, 31TCG304539, 1300 m, 27.2.1986 (0/2/0); coll. Gerecke: E 128 Aragon, Horta de San Juan, Faixa de la Carrasca N Mas de Josepó, rheocrene, 650 m, 17.04.1998 (2/4/1); E 132 Aragon, Beceite, Rio Mataranya, rheohelocrene Acampamento El Parrissal, 650 m, 18.04.1998 (1/1/0); E 164 Albacete, Sra del Segura, nacimiento R. Mundo, cueva Los Chorros, 1100 m, 16.04.1999 (1/3/1).

Material compared: Torrenticola gomerae Lundblad, 1996 : Canary Islands, Gomera, El Cedro, 8.4.1967 holotype 3, SMNH 7083; allotype 3, SMNH 7085; 3 SMNH 7084; Barranco El Cedro (loc.1), 14.10.1995 leg. Smit (1/1/0); Cruce de la Zarcita, eastern stream, ca. 1100 m, 10.03.2006 leg. Allgaier (1/2/0). Torrenticola xylurgella Gerecke & Di Sabatino, 1996 : Corse, Calacuccia, R. Fango, 19.02.1991 leg. Schwarz paratypes (11/44/0).

Discussion: The specimens of T. limula from mountain ranges in Spain agree from most points of view with the original description which was based on specimens from Sardinia and Corsica. Most important characters of the species are, in both sexes: (1) the P-2 ventral margin covered with fine denticles extending to the proximal surface of the segment, its distoventral extension not being clearly set off, (2) excretory pore distanced from the line of primary sclerotization; in males, (3) gonopore with weakly rounded anterior margin, (4) ejaculatory complex with large proximal chamber and relatively small proximal and distal arms. Further characteristics are found in several proportions and measurement values (in parentheses, measurements from Spanish material): Idiosoma roundish (dorsal shield W 3 445-505, Ƥ 490-555); median suture Cx-I relatively long (L 3 155-190, ratio median suture L Cx-I/II+ III 3 1.3-1.6, Ƥ 1.9-2.8); chelicera (L 3 360-430, Ƥ 400-480) and palp (total L 3 294-316, Ƥ 311-329) rather large. From our measurements of palp segments in continental populations results a relatively wide variability (relative L P- 2 30-31 %, P- 3 20-24 %). Consequently, these values are not further suitable for defining the species.

In their discussion of T. limula and T. xylurgella , two new species of the serratipalpis -species group from Corsica and Sardinia, Gerecke & Di Sabatino (1996) did not consider T. gomerae from the Canary Islands, at that time the only known European species of the group. The detection of only provisionally labelled slides containing the last taxa the late Lundblad investigated, prompted the re-examination of the type series of T. gomerae , in comparison with new material from Gomera. Torrenticola gomerae and T. xylurgella have in common (and differ from T. limula in), (1) the P-2 denticulation restricted to the distal quarter of the segment, where the distoventral extension is clearly set off, (2) the excretory pore included in the primary sclerotization and, in males, (3) the gonopore with stronger convex anterior margin and (4) ejaculatory complex being rather slender, with a short proximal chamber and stronger arms. Torrenticola xylurgella differs as follows from T. gomerae (in parentheses): (1) Idiosoma more slender, dorsal shield W <420 (> 440); (2) medial suture Cx-I relatively shorter, ratio median L Cx-I/II+III in males 1.1-1.2 (1.2-1.7), in females 1.4-1.8 (1.9-2.7); (3) palp shorter, L P-4, 80-90 (90-115), total L 230-280 (290-330). In these measurements and proportions, T. gomerae is similar to T. limula from which it differs as described above.

The new records show that T. limula is a crenophilous and hyporheophilous inhabitant of low-order streams. Gil (1990) published two further locality records for T. anomala which probably refer to T. limula also: Spain, Rubiés, fuente del Sito, 1100 m, 27.2.1986; Arén, fuente de la Oliva, 31TCG096913, 1020 m, 29.03.1987.