Scydmaenus (Mascarensia) femoralis Nietner 1856
Creators: name: Jałoszyński, Paweł
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Staphylinidae
Scydmaenus
Scydmaenus femoralis

description: Scydmaenus (Mascarensia) femoralis Nietner
(Fig. 17)
Scydmaenus femoralis Nietner, 1856: 544.
Scydmaenus (Cholerus) femoralis Nietner; Franz, 1982: 132.
Type material. Lectotype (here designated): ♀, three labels: “ Ceylon / Nietner..s” (white, printed and handwritten, text in black frame], QR code label with collection number 8195, and newly added “ SCYDMAENUS / (MASCARENSIA) / femoralis Nietner, 1856 / LECTOTYPUS / P. Jałoszyński, 2025 ” (MIZ).
Revised diagnosis. Each elytral apex truncate and sinuate.
Redescription. Body of female (Fig. 17) strongly elongate and weakly convex, yellowish brown (teneral specimen!); setae of similar color as cuticle; BL 1.20 mm.
Head broadest across small and finely faceted eyes not projecting from head silhouette, HL 0.20 mm, HW 0.25 mm; frontal and vertexal regions confluent, weakly convex, vertex with shallow posteromedian impression; supraantennal tubercles weakly elevated. Punctures on frons and vertex fine and inconspicuous; setae sparse, short and recumbent. Antennae slender, with trimerous clubs, AnL 0.58 mm; antennomere 1 and 2 strongly elongate, 3–5 elongate, 6–8 each transverse, 9 and 10 each about as long as broad, 11 slightly broader than 10, much shorter than 9–10 combined, about 1.5 times as long as broad.
Pronotum inversely subtrapezoidal, broadest near anterior third; PL 0.35 mm, PW 0.33 mm; anterior margin strongly rounded and confluent with lateral margins, which are anteriorly strongly rounded and posteriorly nearly straight; posterior corners obtuse-angled and blunt; posterior margin distinctly arcuate; base with two pairs of small and shallow pits. Punctures on pronotal disc similar to those on frons and vertex; setae short, moderately dense and suberect.
Elytra together oval, broadest slightly anterior to middle; EL 0.65 mm, EW 0.43 mm, EI 1.53; humeral calli not elevated, basal impressions virtually absent; elytral apices truncate and each with sinuate posterior margin. Punctures and setae similar to those on pronotum.
Legs long and slender, metafemur with distinct oblique dorsal impression proximad middle, distally delimited by blunt ridge.
Male. Unknown.
Distribution. Sri Lanka, near Colombo.
Remarks. Only one specimen (a female) is preserved in coll. Nietner. He stated that “My S. femoralis I found under the soft, rotting bark of an Erythrina indica ”, but did not specify the number of specimens. Therefore, the available material must be treated as a syntype, and the single female illustrated in Fig. 17 is here designated as the lectotype. Characters of this specimen perfectly match the Nietner’s description, especially the elytra “slightly truncated at the apex and with a slight sinuosity in the truncature on either side of the suture”, and “the femora are at the place of the juncture rather abruptly narrowed, bent and slightly compressed”. The structure of the hind femora is characteristic of the subgenus Mascarensia. Franz (1982) ignored Nietner’s description and as S. femoralis misidentified a species belonging to the subgenus Cholerus, showing a set of remarkable impressions on the head dorsum in males. The body length of 2.0‒ 2.1 mm given by Franz also clearly indicates a misidentification—the lectotype female is only 1.25 mm long. The specimens examined by Franz and listed in his 1982 paper under the name S. femoralis belong to an undescribed species.
The lectotype is a teneral female, but it shows a character not known in any other member of the subgenus Mascarensia —truncate and sinuate elytral apices. Franz (1982) recorded from Sri Lanka two species of Mascarensia, S. loebli Franz, 1982, and S. ovicollis (Schaufuss 1884). The description of S. loebli contains only the section “ Penis ”, which is explained by a high external similarity to S. dendrophilus Franz 1973 that occurs in Nepal. Not even the measurements are included. Scydmaenus dendrophilus does not have any unusual structures on the elytral apices, so if S. loebli is indeed externally difficult to distinguish from S. dendrophilus, S. femoralis is not conspecific with S. loebli. The identity of Sri Lankan specimens as S. ovicollis, a species that was described based on material collected in Singapore and later recorded from Sumatra, requires verification, especially that most illustrations of aedeagi for this genus published by Franz are not suitable for species identifications, because they show the genitalia in random positions, only rarely in a strictly dorsal or ventral views. If this species indeed occurs in Sri Lanka, it is not conspecific with S. femoralis, not only because of the lack of the elytral modification, but also because of a clearly larger body size.
description: Published as part of Jałoszyński, Paweł, 2025, John Nietner collection of Sri Lankan Scydmaeninae (Coleoptera, Staphylinidae), pp. 79-109 in Zootaxa 5633 (1) on pages 89-90, DOI: 10.11646/zootaxa.5633.1.4, http://zenodo.org/record/15372835