Microcreagrella caeca caeca ( Simon, 1883 )

Zaragoza, Juan A., 2010, Arcanobisium, a remarkable new genus, representing a new subfamily with a relictual distribution from eastern Spain (Arachnida: Pseudoscorpiones: Syarinidae), Zootaxa 2491, pp. 41-60 : 51

Microcreagrella caeca caeca ( Simon, 1883)

Obisium caecum Simon 1883: 279 –280.

Microcreagris caeca (Simon) : Beier 1932: 157.

Microcreagrella caeca (Simon) : Beier 1961: 72 –74, fig. 2.

Material examined. Portugal, Setúbal, Sesimbra, Lapa do Vento, 11 April 2007: 1 female, leg. Pedro Cardoso, deposited in DEUA.

Supplementary description. Carapace, chelicera and pedipalps brownish-red, legs pale and opisthosoma desclerotised. Opisthosoma elongate, all tergites and sternites wide and easy discernible. Tergites I–XI chaetotaxy: 8: 9: 9: 9: 8: 8: 8: 8: 8: 9: 7, opisthosoma ventrally crushed, anal cone with 2+2 setae. Stigmata III and IV each with 4 setae. Pleural membrane laterally striate but also medially weakly granulate.

Body length 2.14 mm. Carapace elongate, 1.37× (0.70/ 0.51 mm), without eyes or eye-spots, with 24 setae, formula 4: 6: 8: 6. Epistome small and weakly prominent.

Chelicera with 5 setae on palm, galea long (0.06 mm) and simple. Hand 2.00× (0.38/ 0.19 mm), movable finger 0.26 mm long. Movable finger with subgaleal seta situated 0.73× from base, dental row ending far basal; fixed finger with 15 medium or small teeth, movable finger with 9 large teeth and 4 weak basal protuberances.

Apex of pedipalpal coxa triangular and long, with 2 distal setae. Trichobothrium ib dorsal, in basal half of hand, eb on antiaxial face of hand and far basal, it level with et and both close to apex of finger, est distal to ist, isb at base of finger, esb on antiaxial distal portion of finger. Trichobothrium t shorter, thicker and more acuminate than others on the movable finger, not flattened or lanceolate, and bent backward; st basal, close to t, distance b -sb 1.49× longer than sb -st, sb not forming group with st -t. A row of 4 antiaxial feather-shaped setae distal of trichobothrium isb. Pedipalps: trochanter 0.39/0.18 (2.14×), femur 0.63/0.21 (3.00×), patella 0.56/0.28 (2.04×) and its pedicel 0.19 long, chela with pedicel 1.05/0.37 (2.82×), hand with pedicel 0.54/0.37 (1.48×), finger 0.55 long.

Junction between femur-patella of leg IV perpendicular, patella 1.41× longer than femur. Subterminal seta with 5–6 apical rami and one internal small medial tooth. Femur+patella 0.53/0.20 (2.70×), tibia 0.48/0.10 (4.80×) TS 0.71, metatarsus 0.15/0.07 (2.16×) TS 0.30, tarsus 0.26/0.005 (4.91×) TS 0.36.

Remarks. Using the key provided by Beier (1963), this specimen is identified by having the chelal finger as long as the hand with pedicel as Microcreagrella caeca caeca , known from the Azores and Canarias Islands. However, the chela and hand are distinctly more slender than in the nominate subspecies; this variability should be verified with more specimens from new localities. The tarsi of each leg are not basally enlarged in this specimen, unlike the sample from Coimbra studied by Mahnert (1980).

The presence of Microcreagrella caeca in mainland Portugal, at the Botanical Garden of Coimbra, was reported by Mahnert (1980), hence it is possible that its presence there was due to the importation of plants from one of the Macaronesian islands (V. Mahnert, in litt.). However, the specimen described above was found in a cave 30 km from Lisbon and more than 200 km from Coimbra, 7 meters deep in a semi-dark zone and under a stone; the outside vegetation was xerophilic and no imported plants were present (Pedro Cardoso, in litt.). Thus it would appear that this species has a wider distribution than previously supposed, being present in continental Europe and the Macaronesian islands, as is the case for Microcreagrina hispanica (Ellingsen, 1910) .