Achilia pachycera Jeannel, 1963

Kurbatov, Sergey A., Cuccodoro, Giulio & Sabella, Giorgio, 2018, A revision of the Chilean Brachyglutini – Part 3. Revision of Achilia Reitter, 1890: A. frontalis species group (Coleoptera: Staphylinidae: Pselaphinae), Revue suisse de Zoologie 125 (1), pp. 165-188 : 170-172

publication ID	https://doi.org/ 10.5281/zenodo.1196048
DOI	https://doi.org/10.5281/zenodo.5589997
persistent identifier	https://treatment.plazi.org/id/A7582020-FF82-FFFF-FEED-FA7856EFEE92
treatment provided by	Plazi
scientific name	Achilia pachycera Jeannel, 1963
status

Treatment

Achilia pachycera Jeannel, 1963 View in CoL

Figs 6-8 View Figs 1-12 , 17, 21 View Figs 13-23 , 83

Achilia pachycera Jeannel, 1963: 353 View in CoL , 363 figs 10 (head and antennae), 11 (aedeagus). ‒ Jeannel, 1964: 10.

Achilia pseudovalidicornis Franz, 1996: 116 View in CoL fig. 64 (aedeagus) syn. nov.

Type material (5 ex.): CENTRAL CHILE: Región Araucanía: Malleco prov.: MNHN; 1 ♂ (holotype of A. pachycera ); Nahuelbuta; 1961; F. Castri. – MNHN; 1 ♂ and 2 ♀ (paratypes of A. pachycera ); same data; F. Castri. – NHMW (coll. Franz); 1 ♂ (holotype of A. pseudovalidicornis ); National Park of Nahuelbuta ; Cordillera Nahuelbuta; 04.XI.1986; H. Franz .

Additional material (150 ex.): See Appendix 1.

Description: Body 1.40-1.50 mm long, usually entirely reddish with black head and palpi yellowish, sometimes with abdomen and pronotum reddish brown. Head with eyes longer than temples. Pronotum wider than head, with maximal width on anterior half; median antebasal fovea as large as lateral ones. First abdominal tergite with basal striae slightly diverging, extending to about one-third of paratergal length, and separated at base by more than one-third of tergal width.

Male: Head similar to A. excisa , flanked on entire length by two very deep pits with outer edge toothed at level of eyes; narrow frontal protuberance slightly convex at base, and distinctly flattened and enlarged anteriorly up to vertexal sulcus. Antennae similar to A. excisa (see Fig. 13 View Figs 13-23 ). Metasternum with large median impression; posterior margin densely pubescent. Legs with ventral margin of mesotrochanters ( Fig. 21 View Figs 13-23 ) forming long and thin spine; profemora and mesofemora slightly thickened; mesotibiae ( Fig. 17 View Figs 13-23 ) bearing subbasal spur slightly recurved externally and apically rounded; metatibiae slightly sinuate on distal half. Abdominal tergites unmodified; first abdominal ventrites with deep median impression with raised edges; all other ventrites distinctly flattened at middle; ventrite I with short median carina extending from posterior margin to posterior edge of median impression. Aedeagus 0.26- 0.30 mm long; similar to A. excisa (see Fig. 1 View Figs 1-12 ), except copulatory pieces ( Figs 6-8 View Figs 1-12 ) consisting of pair of long medial sclerites recurved and strongly sclerotised at base, apically enlarged or pointed, and associated on each side with three or sometimes more short pointed sclerites. Parameres very wide with long seta on poorly developed outer lobe; tips strongly recurved posteriorly and bearing wide and long subapical seta.

Female: Similar to male except: head lacking lateral pits; antennomeres IX and especially X shorter and less enlarged than male; metasternum, abdominal ventrites, and legs unmodified.

Collecting data: Collected from November to February in Nothofagus and Araucaria forests, where it was found from 1100 m to 1300 m. Most specimens came from sifted samples of leaf and log litter, moss, dead trunks, vegetable debris; two specimens were collected by flight intercept traps.

Distribution: Achilia pachycera is known only from the Nahuelbuta District (Malleco Province, Araucanía Region) ( Fig. 83 View Fig : blue triangles).

Comments: Jeannel (1963: 353) first mentioned A. pachycera as a member of the A. spinifer group, however some pages later (1963: 363-364) he correctly places it as a member of his A. frontalis group.

According to Jeannel (1964: 10), A. pachycera is very similar to A. validicornis (now a junior synonym of A. excisa ), from which it differs by the shape of the male frontal protuberance (anteriorly widened in A. pachycera , and constricted in A. validicornis ).

From the abundant material we studied, we could not separate the females of the two species, while the males can be distinguished by the following characters: frontal protuberance of head anteriorly more enlarged in A. pachycera , lateral pits of head of A. pachycera generally deeper and with larger tooth on their outer margin than in A. excisa , features of mesotrochanters (cf. Figs 20, 21 View Figs 13-23 ) and mesotibiae (cf. Figs 16, 17 View Figs 13-23 ) slightly different, as well as metasternum (with medial sulcus in A. excisa , and bearing a large impression in A. pachycera ) and abdominal ventrites (slightly flattened at middle for A. excisa , clearly flattened for A. pachycera ). Achilia pachycera also differs from A. excisa by the morphology of the copulatory pieces of the aedeagus, which exhibit constant and stable differences, especially with respect to the location of the three pointed pairs of internal sclerites, which are either fused ( Figs 1, 4-5 View Figs 1-12 ) or disconnected ( Figs 6, 8 View Figs 1-12 ). Within the light of these slight but nevertheless constant differences, we consider it appropriate to maintain A. pachycera as a valid species.

Examination of the holotype and only known specimen of A. pseudovalidicornis revealed that both external and aedeagal characters fit perfectly our concept of A. pachycera Jeannel, 1963 . Therefore we conclude that A. pseudovalidicornis Franz, 1996 must be considered to be a junior synonym of A. pachycera Jeannel, 1963 (syn. nov.).