Theridula aelleni ( Hubert, 1970 )

Knoflach, Barbara, Rollard, Christine & Thaler, Konrad, 2009, Notes on Mediterranean Theridiidae (Araneae) – II, ZooKeys 16 (16), pp. 227-264 : 257-260

Theridula aelleni ( Hubert, 1970) stat. n., comb. n.

Figs 80-84

Theridion aelleni Hubert, 1970: 190 , figs 1-4, male female, type locality: Tunisia, Gr. des Chauves-Souris, El-Haouaria, 3.10.1967. Resurrected from synonymy with Theridion spinitarse O. P.- Cambridge, 1876 (contra Brignoli 1984), comb. n.

Type material examined. Female holotype, male allotype, MHNG, Tunisia, Gr. des Chauves-Souris, El Haouaria, 3.10.1967, leg. P. Strinati, M. Frainier and V. Aellen, det. M. Hubert 1969.

Further material examined. Spain: Cadiz, Embalse de Palmones, 1 ♀ (in collection J. van Keer), 16.3.1994, leg. J. van Keer.

Description, identification. Hubert (1970).

Measurements (n=3, holotype female/ allotype male/ female from Spain): Total length 2.4/2.0/3.2, carapace length 1.0/0.9/1.1, width 0.9/0.8/1.0, length femur I 1.3/1.4/1.5, tibia I 1.2/1.3/ 1.2 mm.

Somatic features, colouration. Specimens from Tunisia uniformly pale yellow, probably faded (but see Hubert 1970). The female from Cadiz shows an indistinct pattern: Carapace light brown with faint dusky margins and median band. Sternum dusky grey. Legs uniformly pale yellowish. Abdomen grey, with three pairs of pale transverse, oval patches, arranged in diagonal paramedian rows. Venter uniformly grey. Spinnerets contrastingly light. Male chelicerae longer than in female. Abdomen globular, a little longer than wide, without protuberances. For further details see Hubert (1970).

Male palp ( Figs 80-82 ). Tibia rather asymmetrical, retrolaterally fairly extended ( Fig. 80 ), but prolaterally excavated ( Fig. 82 ), its distal rim in ventral-prolateral view oblique and almost reaching patella ( Fig. 81 ). Two trichobothria present on retrolateral side of tibia. Cymbium elongate and slender, its base occupying prolateral side of palp, where it is markedly incised. Cymbial hood in dorsal-median position. Subtegulum and tegulum constitute the main part of genital bulb and are densely crossed by wide loops of sperm duct. The embolus forms a straight element inserted deeply within the tegulum. Subtegulum with strongly protruding sclerotised basal shaft, which is embedded within a cavity and surrounded by a noticeably developed basal haematodocha. Distal part of embolus conspicuously screwed. Embolar base encircled by a membranous apophysis, which interlocks with cymbial hood and thus is interpreted as the median apophysis.

Epigynum /vulva ( Figs 83-84 ). Copulatory orifices roughly circular, ca. 0.6 mm wide, with marked, sclerotised outlines. They are clearly separate, but less than their diameter apart. Their distance to epigastric furrow equals about their diameter. Copulatory ducts rather short, forming a small coil, at entrance rather wide, narrowing towards receptacula. Receptacula seminis barely larger than copulatory orifices.

Taxonomic remarks, generic placement. The former synonymy of Theridion aelleni with T. spinitarse by Brignoli (1984: 301) was concluded from illustrations only and cannot be supported here. Along with the present analysis of type material the resurrection of T. aelleni has to be confirmed (for comparison see Theridion spinitarse above). However, the generic placement among Theridion evidently implies some difficulty. The new allocation offered here may be surprising and not fully satisfactory when considering the general appearance of hitherto known Theridula species, which is known to be striking, mainly through a tuberculate and wide abdominal shape, often combined with bright colour. Especially the unmodified abdomen of T. aelleni at first glance argues against placement within Theridula , but would suggest resemblance with the only hitherto known species of Paratheridula (see Levi 1957b). However, a transfer of the species into Theridula is suggested, mainly owing to characters of the male palp: 1. Membranous median apophysis adjoining embolus and arresting towards cymbial hood (= distal haematodocha according to Levi 1954, 1966 and Levi and Levi 1962, Heimer 1982; median apophysis according to Agnarsson 2004: 596). 2. Distal part of embolus screw-shaped. 3. Asymmetry of tibia. 4. Prolateral incision of cymbium. 5. Female genitalia of concordant structure. In Paratheridula a median apophysis (distal

membrane) is reported to be completely missing, which appears to be the main criterion for its separation from Theridula ( Levi and Levi 1962) .

Distribution. Theridula aelleni is so far known only from the type locality in Tunisia and from Spain.

Figures

Figures 80-84. Theridula aelleni (Hubert) from Tunisia. Male palp, retrolateral (80), ventral (81), prolateral view (82). Epigynum/vulva, ventral (83), dorsal view (84). 80-82 and 83-84 drawn at same scale. Scale lines: 0.20 (80-82) and 0.10 mm (83-84).