Starengovia Snegovaya, 2010

Jochen Martens, 2017, On Starengovia Snegovaya, a genus of Asian nemastomatines (Arachnida: Opiliones: Nemastomatidae), Revue suisse de Zoologie 124 (2), pp. 187-201 : 187-188

Genus Starengovia Snegovaya, 2010

Type species: Starengovia kirgizica Snegovaya, 2010: 351 (by monotypy).

Remarks: A genus of Nemastomatidae in the subfamily Nemastomatinae , presently comprising two species. Gender of genus name is female.

Emended diagnosis: Small species (up to 1.7 mm body length, females being larger than males), dorsal scutum with lines of anvil-shaped tubercles along margins of all scutal areas. Pairs of marked para-median tubercles on opisthosomal areas of dorsal scutum. Apophysis on basal cheliceral article of male well-marked but low, with a distad-directed hook, discharge area for secretion in a bowl-like excavation on medial side of apophysis. Its inner wall perforated by numerous minute pores, apparently the extrusion area for cheliceral gland secretion.

Genital morphology of males: Characterized by rather unspecialized truncus penis, moderately slender, not markedly inflated; muscle-containing inflated base of penis large, rather compact, deeply incised medially, occupying about one fourth to one third of truncus length, truncus in straight continuation of inflated base. Glans inconspicuous, small, short, not well differentiated from truncus; armament of glans simple, with few stiff spicules in a dorsally and ventrally symmetrical arrangement, stylus short, straight to slightly curved.

Distribution: Hitherto only two males of one species were known from Kyrgyzstan, a second species is here described from Pakistan. Staręga (1986) provisionally named a single female from the Tadjik Republic as “ Mediostoma ” pamiricum Staręga, 1986 . The locality of this specimen is about half way between and approximately 360 km from Starengovia records in Kyrgyzstan and in Pakistan and thus this female may also belong to Starengovia . This assumption is backed by characters of external morphology ( Fig. 6B ; see Discussion).

Name: It refers to Wojciech Krzysztof Staręga (1939- 2015), a distinguished Polish arachnologist who worked on systematics and taxonomy of European, Asian and African harvestmen ( Żabka, 2015).

Relationships: Rows of anvil-like tubercles forming lines and encircling the dorsal scutum magnum or parts of it and all or some of the dorsal scutal areas (probably equivalents to “somites”) are present in several nemastomatine genera and are documented for Mitostoma Roewer, 1951 , Carinostoma Kratochvíl, 1958 ( Martens, 1978a) and Acromitostoma Roewer, 1951 ( Rambla, 1983) . These structures are excessively developed in all New World ortholasmatines. According to the (still incomplete) molecular-based results of Schönhofer & Martens (2012), these dorsal ornaments developed independently in at least two different lineages. Two of the relevant genera analyzed, namely Carinostoma and Mitostoma , are placed on different branches of the molecular-based tree and are not closely related.

Alternatively, this dorsal armament may have been lost at various stages of nemastomatine evolution. This assumption is backed by the fact that nearly all ortholasmatine genera and species exhibit rich and elaborate scutal ornamentations. It is reduced in the few known Asian species ( Shear & Gruber, 1983; Shear, 2010; Zhang & Zhang, 2013). Thus, lines of anvil-shaped tubercles may represent a plesiomorphic character within the Nemastomatidae , an element of the nemastomatid “Bauplan”. In addition, equally shaped thorns turn up as coxal-rim denticles in most species of Nemastomatidae . If plesiomorphic, this character would not be useful to infer phylogenetic relationships.

Figures

Figs 5 - 6 B. Body of male in lateral view (5 - 6 A) and in dorsal view (6 B). (5) Starengovia kirgizica. (6 A) S. ivanloebli sp. n. (6 B) Mediostoma pamiricum Staręga, 1986; reproduced from Staręga (1986). Scale: 1 mm.