Arboricaria Bosmans, 2000

Mikhailov, Kirill G., 2016, On the spider genus Arboricaria with the description of a new species (Araneae, Gnaphosidae), ZooKeys 558, pp. 153-169 : 155-156

Taxon classification Animalia Araneae Gnaphosidae

Arboricaria Bosmans, 2000

Arboricaria Bosmans, in Bosmans and Blick 2000: 460-461.

Arboricaria Tuneva 2007: 250.

Type species.

Micaria cyrnea Brignoli, 1983.

Composition.

Arboricaria includes five known species listed above and one new species described below.

Despite not being followed on the world spider catalogues (see above), the original description of Arboricaria and its diagnosis both fully fit the provisions of the International Code of Zoological Nomenclature, especially Articles 13.1 and 67.4 ( ICZN 1999), i.e., diagnostic characters are sufficient for recognizing the new genus, as well as the type species is properly indicated. So there are no formal grounds to reject the validity of Arboricaria .

According to the original diagnosis, the new genus "is very close to Micaria and differs by the more flattened, wider cephalothorax, the less spinate legs and the posteriorly truncate sternum. Males differ by the large tibial apophysis, bifid or curved, the bulging bulbus and the absence of the median apophysis (= Retinaculum in Wunderlich 1980), females by the large epigyneal fossa [= groove] with distinctly chitinized posterior margin". In addition, the Micaria subopaca -group is characterized by 0-2 distal-ventral spines on the cymbium, as well as the absence of ventral spines on tibiae and metatarsi I–II ( Wunderlich 1980: 249).

Not all of the characters are equally important.

The width of the carapace is variable within the remaining Micaria (cf. Table 1 herein with table 1 in Wunderlich 1980). In Micaria sensu stricto, the carapace length/width index is 1.2-2.0.

The same concerns the size of the tibial apophysis (for large ones in Micaria , see figs 29a, 31a, in Wunderlich 1980), not bifid in Micaria , as well as in Arboricaria subopaca .

A median apophysis is absent or almost absent in Micaria rossica Thorell, 1875, wholly absent both in Micaria utahna Gertsch, 1933 and Micaria medica Platnick & Shadab, 1988.

An analysis of leg spination (see table 1 in Wunderlich 1980: 250-251) shows that Arboricaria species fall within the range of Micaria variability, yet close to its marginal part.

The shape of the posterior part of the sternum is clearly different in Micaria and Arboricaria (see Figs 1-5).

Therefore, the above diagnosis of Arboricaria must be adjusted. This genus is indeed close to Micaria , but differs in the following characters that together allow recognizing the genus: a posteriorly truncate sternum in both sexes, a bulging bulbus and a missing median apophysis, a chiefly bifid tibial apophysis, a large epigynal groove with distinctly chitinized posterior margins in females. At least, the shape of bulbus and bifid apophysis can be regarded as apomorphic characters. All these characters constitute Arboricaria as a monophyletic and sister-group to other Micaria . An extended description of Arboricaria is available in Bosmans and Blick (2000).

The distribution pattern of Arboricaria is mostly Mediterranean and on the mountain regions of central Asia, although Arboricaria subopaca extends to most of the Palearctic.