Jacaena, Thorell

Deeleman-Reinhold, Christa, 2001, Forest Spiders of South East Asia With a revision of the sac and ground spiders (Araneae: Clubionidae, Corinnidae, Liocranidae, Gnaphosidae, Prodidomidae and Trochanteriidae)., Forest Spiders of South East Asia With a revision of the sac and ground spiders- Family Liocranidae, Leiden, Netherlands: Brill Leiden; Boston; Köln, pp. 400-505 : 465

Genus Jacaena Thorell

Jacaena Thorell, 1897: 230 . Type species: J. distincta Thorell, 1897 , no figures, ♀. Burma, Tenasserim.

This genus was described by Thorell (date of issue 2 january 1897) in the Clubionidae in the subfamily Thamphilinae (=Sphingiinae). This subfamily was composed of the genera Thamphilus, Sphingius and Jacaena . Thamphilus Thorell 1895 was soon synonymised with Sphingius (Simon, 1897, HNAII: 158). Apparently, Simon did not see any specimens of Jacaena , but he did somehow receive Thorell’s data before the first part of HNAII went to press. Consequently, he mentioned the genus only in a footnote (1897, HNA II: 157, date of issue 15 february 1897), where he placed it close to Sphingius . Simon ranged Sphingius erroneously in the Molycriae, a tribe he wrongly believed to belong to the subfamily Micariinae and which originally included Molycria and Myandra . Bonnet 1959, (2[5]:4395) recognised the genus Thamphilus, but subsequent cataloguers Roewer, Brignoli and Platnick followed Simon in synonymising Thamphilus with Sphingius . Today, the Micariinae are mainly defined by the apomorphic iridescent scales on the abdomen, which alienate them from all groups treated here. It is now clear that for Sphingius and Jacaena there is no close relationship at all with either Myandra or Molycria . Simon’s reassessment of the taxonomic position of both these genera was very much beside the mark. The genus Jacaena : “genre....différant surtout des autres (Molycriae) par ses tibias antérieurs armés de deux séries d'épines”. Roewer (1954) followed Simon; Reiskind (1969: 166) moved Sphingius to the Corinninae and moved the bulk of Micariinae as a whole to the Gnaphosidae , and in this latter family Jacaena remains in Platnick 1989, 1991 and 1998. During my stay in Genova 1986 and 1989, I found there was no specimen labelled Jacaena distincta in existence. However there was one female labelled Cadicus distinctus, agreeing fully with the description of J. distincta , including the unusual pattern of the upper- and underside of the abdomen, and which was taken at the same locality Tenasserim: Mooleyit. No species by the generic name of Cadicus has ever been published. I consider this case as an inadvertent omission by Thorell to adjust the name on the label to that in the description and I recognise the specimen as the type of Jacaena . Jacaena distincta is closely related to Sesieutes . The principal distinction between the two is in the extraordinary structure of the vulva, which is shared with J. mihun sp. n. described below. This argument is used here to maintain Jacaena as a valid genus.

Described species.— Jacaena distincta Thorell, 1897 , ♀, Myanmar (Burma); J. mihun sp. n., ♂♀, C and N Thailand, this volume.

Diagnosis.— Jacaena is similar in most respects to Sesieutes . It is distinct from Sesieutes in the construction of the vulva: this consists of a pair of seemingly non-differentiated, meandering and coiling tubes without distinct spermathecae. In the type species the male is unknown; in Jacaena mihun males, described below, the embolus is transformed into a short broadened rigid appendage. The clypeal lobe is reduced.

Old material studied.— Jacaena distincta , 1 ♀, Burma, Tenasserim, MCSNG.

Data on Behaviour.— Ground-living.

Distribution.— Southeastern Myanmar (Burma) and Thailand.