Arabelia, Bosselaers, Jan, 2009

Bosselaers, Jan, 2009, Studies in Liocranidae (Araneae): redescriptions and transfers in Apostenus Westring and Brachyanillus Simon, as well as description of a new genus, Zootaxa 2141, pp. 37-55 : 49-51

Arabelia gen. n.

Figs. 2 K ; 7 A–G; 8 H; 9.

Diagnosis. Arabelia is close to Andromma Simon 1893 from Africa ( Ethiopia, Central and South Africa), but differs from this genus by its single chilum, flattened as opposed to slender PMS, presence of feathery hairs, spineless ti and mt III, absence of true claw tufts and presence of epigynal hood. Arabelia can be distinguished from all other liocranids by the almost spineless legs III and IV and the combination of large CO of the vulva and a narrow, anterior epigynal hood.

Description. Small (2–4) spiders. Carapace unicolorous reddish brown ( Fig. 9 ), fading to orange in ethanol ( Fig. 8 H ). A short but distinct fovea in posterior third. Chilum small and weakly sclerotised, single, triangular. PLB weak and thin, isolated. Eyes in two transverse rows of four, in fr view AER slightly recurved and PER slightly procurved (Fig. 7 D); in do view both eye rows recurved (Fig. 7 A). All eyes subequal, AME circular, LE oval, PME subtriangular. ALE and PE pearl, AME with dark retina restricted to median half of eye. MOQ widest posteriorly. Clypeus slightly larger than diameter of AME. Chelicerae yellow-brown, slightly bulging, tapering towards tip. Fangs sickle-shaped, with one large, knee-shaped seta and a row of long curved setae in front. Sternum shield shaped, smooth, yellow-brown in ethanol. Small PCT present, no ICS. Labium subtrapezoidal, with thickened anterior rim, slightly longer than wide. Endites subrectangular, frontally rounded, with oblique depression, apical hair tuft and serrula. Legs unicolorous pink in living animal ( Fig. 9 ), fading to yellow ochre in ethanol ( Fig. 8 H ). No rh, no trochanter notch. Patellar indentation long and narrow, 1/2–2/3 of pa length. Leg formula 1423. Femora with one basal do spine, ti I and II with 5 ve spine pairs, mt I and II with 3 ve spine pairs, legs III and IV almost spineless. Sparse ve preening brush on mt III and IV. Tarsi without claw tufts, but with several pairs of tenent hairs, claws pectinate.

Abdomen pink ( Fig. 9 ), fading to pale yellow in ethanol ( Fig. 8 H ), covered with pointed grey hairs. Small and weak inframamillary sclerite present (Fig. 7 G). ALS conical, separated by their width, with short apical segment. PMS large and compressed, with three large cylindrical gland spigots and one minor ampullate gland spigot. PLS cylindrical, separated by their length, with large white apical segment 1/3 of total length of spinneret bearing two large cylindrical gland spigots (Fig. 7 G).

Epigyne with small anterior hood (Fig. 7 F), vulva with anterior CO, posterior ST1 and small ST2 (Fig. 7 E).

Etymology. The genus name Arabelia refers to the Belgian Arachnological Society Arabel ( Jocqué 2004; http://www.arabel.ugent.be/), which organised expeditions to the Greek islands, during which the new species was collected.

Discussion. Whether Arabelia should be placed in Corinnidae or Liocranidae remains a matter of debate, since both families lack distinct synapomorphies ( Platnick & Baptista 1995; Bosselaers & Jocqué 2002; Wunderlich 2008). Eye morphology, leg spination and clear myrmecophyly (see below) suggest a proximity of Arabelia to Andromma , a genus which is traditionally placed in Liocranidae ( Platnick 2009) , but ended up in the corinnid clade in an analysis by Bosselaers & Jocqué (2002). However, the affinities of enigmatic dionychan genera such as Andromma and Hortipes (which also has almost spineless legs III and IV) remains unclear and their place in cladograms has not yet stabilised. Arabelia is attributed to Liocranidae based on its flat carapace, narrow eye field, lack of conspicuous abdominal sclerotisation and presence of an anterior epigynal hood similar to Liocranum and Mesiotelus .

Figures

FIGURE 9. Arabelia pheidoleicomes sp. n., Lesbos, Agiasos, pine wood near Megali Limni, live animal on underside of stone, among Pheidole ants.

FIGURE 2 A – K. Leg spination schematics. A, legend; B, Apostenus humilis, male holotype; C, Apostenus humilis, female, MNHN 25; D, Apostenus ochraceus, female; E, Agraecina rutilia, female holotype; F, Agraecina lineata, female, MNHN 5653; G, Cybaeodes liocraninus, holotype; H, Cybaeodes testaceus, female holotype, MNHN 3107; I, Cybaeodes madidus, female holotype, MNHN 1677; J, Cybaeodes marinae, female, Italy, Castelporziano, AMNH; K, Arabelia pheidoleicomes, female holotype.

FIGURE 8 A – H. Dorsal views of specimens. A, Apostenus humilis, holotype; B, Apostenus ochraceus, Lesbos, Kratigos; C, Agraecina rutilia, holotype; D, Agraecina lineata, female, MNHN 5653; E, Cybaeodes liocraninus, holotype; F, Cybaeodes testaceus, holotype; G, Cybaeodes madidus, holotype; H, Arabelia pheidoleicomes sp. n., Lesbos, Agiasos, Megali Limni. Scale bars: 0.5.