Achilia excisa
Creators: name: Kurbatov, Sergey A.
name: Cuccodoro, Giulio
name: Sabella, Giorgio
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Achilia
Achilia excisa

description: Achilia excisa (Schaufuss, 1880)
Figs 1, 4-5, 13, 16, 20, 53, 55, 57, 83
Bryaxis excisa L. W. Schaufuss, 1880: 494;
Achilia excisa Jeannel, 1962: 407, 408 fig. 157 (head).
Bryaxis validicornis Reitter, 1885: 325, 328 pl. 2 fig. 9 (head) syn. nov.
Achilia validicornis Jeannel, 1962: 407 figs 155 (habitus), 156 (aedeagus). ‒ Jeannel, 1964: 10.
Type material (2 ex.): MNHN (ex coll. Raffray); 1 ♂ (lectotype of A. excisa, by present designation); Cuba (labelling mistake). – MNHN; 1 ♂ (lectotype of A. validicornis, by present designation); Chili.
Additional material (1432 ex.): See Appendix 1.
Description: Body 1.35-1.50 mm long, entirely reddish with darker head and palpi yellowish, or with black head, pronotum and abdomen reddish brown, and elytra, antennae, and legs reddish. Head with eyes longer than temples. Pronotum slightly wider than head, with maximal width on anterior half; median antebasal fovea large as lateral ones. First abdominal tergite with basal striae slightly diverging, extending to less than one-third of paratergal length, and separated at base by about onethird of tergal width.
Male: Head as in Figs 53 and 55, flanked on entire length by two deep lateral pits with outer edge toothed at level of eyes (Fig. 57); narrow frontal protuberance slightly convex at base and flattened anteriorly to vertexal sulcus. Antennae (Fig. 13) with scape and pedicel longer than wide; antennomere III as wide as long; antennomeres IV- VIII slightly transverse; antennomeres IX and X strongly transverse with protruding mesal margins bearing long bristles; antennomere X very large, wider and longer than IX; antennomere XI elongate, as long as VIII-X combined. Metasternum slightly raised in middle, this area with wide median sulcus. Legs with ventral margin of mesotrochanters (Fig. 20) forming long and stout spine; profemora and mesofemora slightly thickened; mesotibiae (Fig. 16) bearing long subbasal spur slightly recurved externally; metatibiae slightly sinuate on distal half. Abdominal tergites unmodified; first abdominal ventrites with faint median impression, all other ventrites flattened at middle; ventrite I with distinct median carina extending from posterior margin to posterior edge of median impression. Aedeagus (Figs 1, 4-5) 0.26-0.30 mm long; dorsal plate ovoid with dorsal longitudinal struts divergent; copulatory pieces consisting of pair of long medial sclerites recurved and strongly sclerotised at base, and apically forked and pointed, associated on each side with three pointed sclerites. Parameres very wide with wide and 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 thickened than for male; antennomere XI as long as VII-X combined; metasternum, abdominal ventrites, and legs unmodified.
Collecting data: Collected from October to February, mainly in Valdivian rainforests, but also in Saxegothaea forests, where it was found also in remnants and in boundary forests at elevations ranging from sea level to 1000 m. Most specimens came from sifted samples of leaf and log litter, moss, dead trunks, vegetable debris and sometimes mushrooms, and from flight intercept traps. Rarely collected by windows traps and car nets.
Distribution: Achilia excisa is relatively common (Fig. 83: red circles) in the central region of Chile from Chiloé Province to Malleco Province. In the MNHN we have examined 3 females from Zaparral 20.IX.1957, G. Kuschel (Región Valparaíso, Petorca Province) belonging to the A. frontalis group, which, lacking the males, we cannot attribute with certainty to any species.
Comments: Schaufuss (1880: 494) described Bryaxis excisa based on three specimens, two labelled as being from Cuba, whose provenance was guaranteed by Zahlmeister Riehl, and one from Chile, with whose provenance Schaufuss had doubts. Reitter (1885: 325, 328) described Bryaxis validicornis on the basis of two males collected in Valdivia, one by Lady Kindermann and the other by Riehl, but he did not mention Bryaxis excisa. Jeannel (1962: 407-408) redescribed these two species under the generic name Achillia (misspelling), and distinguished them from others by the form of the lateral pits of the head: reaching beyond the posterior edge of the eyes and with the lateral margin not toothed in A. excisa, and not reaching the posterior edge of the eyes and with the lateral margin toothed in A. validicornis.
Concerning Achilia excisa Jeannel (1962: 408) considered it unlikely that it was from Cuba, and asserted that it was certainly collected in Chile, despite mentioning the type, preserved in MNHN, was labelled as being from Cuba.
We examined all the material of the MNHN collection and found in Raffray’s collection one specimen of A. excisa labelled as “ Cuba /Type [red label]/ A. excisa Raffray det.”, and one specimen of A. validicornis labelled as “ Chili /Type [red label]/ A. validicornis Raffray det.”. We consider these two male as the lectotypes of A. excisa and A. validicornis, respectively, and have labelled them accordingly.
The aedeagi of the two above-mentioned specimens are partially damaged, nevertheless they appear similar in respect to both the shape of the parameres and the structure of copulatory pieces. Our study of the very abundant additional material shows also that the differences highlighted by Jeannel in the features of the head between A. excisa and A. validicornis were overestimated and pertain to intraspecific variation, and particularly that the lateral pits of the male of the lectotype of A. excisa are toothed at level of eyes; consequently we here place A. validicornis (Reitter, 1885) as the junior synonym of A. excisa (Schaufuss, 1880) (syn. nov.).
Achilia excisa is a very common species in Central Chile, and the genus is so far unknown outside of central and southern Chile and southern Argentina. Thus we consider that the occurrence of this species in Cuba can be ruled out with a high level of confidence, and that this locality record is most likely due to a labelling mistake.
description: Published as part of 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), pp. 165-188 in Revue suisse de Zoologie 125 (1) on pages 166-169, DOI: 10.5281/zenodo.1196048