Stiphromyrmex robustus

While the type and subsequent material studied by Wheeler has been lost, another specimen has been found is designated as the neotype.

Identification
Radchenko and Dlussky (2017) - The monotypic genus Stiphromyrmex is mainly characterized by the 12-segmented antennae with the big 3-segmented club, by the short and stout mesosoma that is distinctly narrower than the head; the promesonotum convex, the promesonotal suture and metanotal groove are absent; the propodeum with the very big, massive curved spines, directed upward and backward at an angle ca. 55°; the middle and hind tibiae are with simple spur. The frontal lobes poorly developed, only partly covering the antennal sockets. The clypeus is with two longitudinal carinae. The maxillary palpes are 4-segmented, labial palpes – 3-segmented (Wheeler 1915).

Distribution
This taxon was described from Baltic Amber (Eocene).

Castes
Known only from the worker caste.

Nomenclature

 * † robustus. †Stigmomyrmex robustus Mayr, 1868c: 97, pl. 5, fig. 101 (w.) BALTIC AMBER (Eocene). Combination in †Stiphromyrmex: Wheeler, W.M. 1915h: 67.

Worker
Radchenko and Dlussky (2017) - Neotype. HL 0.88, HW 0.77, SL 0.59, OL 0.21, ML 1.07, PNW 0.61, PL 0.40, PW 0.19, PPL 0.19, PPH 0.19, PPW 0.24, HTL 0.53, ESL 0.43, ESD 0.37, total length ca. 3.25 mm. `Ratios. HL/HW 1.14, SL/HL 0.67, SL/HW 0.77, OL/HL 0.24, PL/HL 0.45, PPL/HL 0.22, PPL/PPH 1.00, ESL/HL 0.49, ESL/ESD 1.16.

Type Material
Radchenko and Dlussky (2017) - The holotype of Stiphromyrmex robustus, as well as two specimens investigated by Wheeler, seem to be lost. There are no any parts of the old amber collections, including material of E. Berendt, in the MIBUG (E. Sontag, personal communication, 2016), as well as in the GZG.BST (A. Gehler, personal communication, 2017), where part of the old Konigsberg’s collection is preserved (see also Dlussky and Radchenko 2006a). Therefore, we designate here the neotype of S. robustus: worker, Baltic amber, No. 8483, MZ PAN. The neotype specimen completely matches the descriptions and figures of Mayr (1868) and Wheeler (1915). As the mentioned descriptions are comprehesive, we do not formally redescribe the neotype specimen, only provide the morphometrics data.