Aleocharina (Tinotus)

Yamamoto, Shuhei & Maruyama, Munetoshi, 2016, Revision of the subgenus Tinotus Sharp, stat. n., of the parasitoid rove-beetle genus Aleochara Gravenhorst (Coleoptera, Staphylinidae, Aleocharinae) from Japan, Taiwan, and the Russian Far East, ZooKeys 559, pp. 81-106 : 82-83

Taxon classification Animalia Coleoptera Staphylinidae

Subgenus Tinotus Sharp, 1883 stat. n.

Tinotus Sharp, 1883: 170. Type species: Tinotus cavicollis Sharp, 1883. Fixed by Fenyes 1918: 25, by subsequent designation.

Exaleochara Keys, 1907: 102. Type species: Tinotus morion Gravenhorst, 1802. Fixed by Klimaszewski et al. 2002: 284, by monotypy. As synonym of Tinotus : e.g., Bernhauer & Scheerpeltz 1926: 713; Blackwelder 1952: 163; Ashe 2000: 360; Hanley 2002: 457; Klimaszewski et al. 2002: 284; Gouix and Klimaszewski 2007: 30; Schülke and Smetana 2015: 505.

Acrimea Casey, 1911: 14. Type species: Acrimea resecta Casey, 1911. Fixed by Fenyes 1918: 20, by subsequent designation. Synonymized by Gusarov 2003: 353.

Tinotus See further references in Hanley (2002), Klimaszewski et al. (2002), and Gusarov (2003).

Diagnosis.

This subgenus is rather easily distinguished from the other congeneric taxa by 1) compact, small (<4 mm), and 2) strongly spindle-shaped body; 3) 4-5-5 tarsal formula (5-5-5 in the other subgenera of Aleochara ); 4) fully carinate mesoventrite; 5) wide and 6) truncate apex of intercoxal process of mesoventrite, 7) and its apex reaching to apex of intercoxal process of metaventrite; 8) median lobe of aedeagus with developed flagellum; 9) female spermatheca without apical invagination of spermathecal head (sensu Welch 1997) and, 10) coiled basally. Minute characters on mouthparts probably define the subgenus as well, e.g., setula a on the first segment of labial palpi located at nearly apical margin of the segment (Fig. 5; see also Sawada 1987).

Remarks.

See other characters mentioned in detail by Hanley (2002) and Klimaszewski et al. (2002).

Systematic position.

Sharp’s (1833) original description of Tinotus placed this taxon in the group Myrmedoniina (= Lomechusini ) due to its 4-5-5 tarsal formula. Since, Tinotus has also been placed in Hoplandriini (e.g., Seevers 1978) or Aleocharini (e.g., Lohse 1974), mainly based on the presence of a pseudosegment on the maxillary and labial palpi (see Hanley 2002 for a historical review).

In contrast to these ambiguities, recent studies have refuted all tribal placements other than Aleocharini . Hanley (2002) recognized Tinotus within Aleocharini , suggesting a close relationship with the genus Aleochara , based on the seven shared morphological characteristics of the genus, e.g., bifid to crescent-shaped apex of the ligula. According to the extensive molecular study of Aleochara by Maus et al. (2001), Tinotus was fully resolved within the " bilineata clade" of Aleochara . Similarly, Osswald et al. (2013), who used significantly fewer species (only four species of Aleochara , one of which is Tinotus ) but analyzed them with much more molecular markers (4599 bp), also supported the assignment of Tinotus to Aleochara .

In our morphological study of Tinotus and Aleochara species, we found numerous morphological similarities between these genera, including a long intercoxal process of mesoventrite, except for the 4-5-5 tarsal segmentation in Tinotus (5-5-5 in Aleochara ). Among the subgenera of Aleochara , Tinotus shares characters with the subgenus Xenochara Mulsant & Rey, 1874, i.e., carinate mesoventrite and fusiform body (including convexed pronotum). Remarkably, the subgenus Coprochara Mulsant & Rey, 1874 seems to be significantly more closely related to Tinotus . In fact, they share some important characters, including a completely carinate mesoventrite and a coiled spermatheca ( Yamamoto and Maruyama 2013). Maus et al. (2001) also implied that both subgenera are phylogenetically close to Tinotus . Reduction of the antennal segment or tarsal segmentation in Aleocharinae is associated rather frequently with miniaturization of their body size (e.g., tribes Hypocyphtini and Mesoporini ), and Tinotus species are possibly no exception. Therefore, no significant character exists to distinguish Tinotus from Aleochara at the genus level. We herein transfer Tinotus , as the 19th subgenus, to the genus Aleochara .