Mascarensia Franz

Jałoszyński, Paweł, 2023, Scydmaenus Latreille of Australia: Revision of species in subgenera Choleropsis Franz, Kingius Franz, Mascarensia Franz, Parallomicrus Franz, Scottiscydmaenus Franz, and description of Ascydmaenus subgen. n. (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5371 (1), pp. 1-75 : 37

Subgenus Mascarensia Franz

Mascarensia Franz, 1973: 120 (as subgenus of Scydmaenus ; not as new). Type species: Scydmaenus dendrophilus Franz, 1973 (monotypy). Note: Franz (1973) referred Mascarensia to his work in press (“Das Subgenus Mascarensia wird von mir in dem die Scydmaeniden umfassenden Band der Faune de Madagascar beschrieben. Typusart ist die gleichzeitig beschriebene Art Mascarensia reunionis m. Der Band der Faune de Madagascar befindet sich im Druck.”) and designated Scydmaenus reunionis as the type species, which was not available until the delayed publication of Franz (1986).

Diagnosis. The subgenus Mascarensia was defined as having in both sexes the hind femur strongly “eingeschnürten” (i.e., constricted) and bearing a deep and clearly delimited pit. Other characters included the head lacking any pits or grooves, a symmetrical antennal club lacking any peculiar features, the pronotum with two antebasal pits, elytra lacking distinct basal impressions and with weakly marked humeri, protarsi in males not broadened, metanepisterna fully separated from the metaventrite, and the apical region of the aedeagus demarcated by a constriction ( Franz 1973).

Remarks. The above-mentioned features can be found in the sole Australian species, except that there are two pairs of indistinct antebasal pronotal pits instead of one pair.A brief discussion of character variability in Mascarensia was given by Jałoszyński (2022). The proximal flattening with a variously developed pit on the metafemur ( Figs 101–102 ) are the only unique characters that distinguish Mascarensia from all remaining subgenera of Scydmaenus . The aedeagal structure (variable, but in all species with the distal region broadened and delimited by a weakly to strongly developed constriction) is similar to the condition found in the type species of Cholerus ( Jałoszyński 2013), but relationships between these subgenera are unclear. The submentum of Mascarensia ( Fig. 97 ) has a pair of conspicuously large, anteriorly projecting lamellate lobes that overlap with the mentum. This character can be another diagnostic feature for this subgenus. However, the structure of the submentum is unknown in the (still inadequately studied) type species of Mascarensia .

Composition and distribution. Mascarensia currently includes 11 species distributed in Asia ( Bhutan, Indonesia: Sumatra, Japan: Honshȗ, Malaysia: Sabah, Nepal, Singapore, Sri Lanka); continental Australia; and islands of the Indian Ocean: Mauritius, Réunion, and Seychelles: Praslin. In Australia only one species.

Figures

FIGURES 101–102. Scydmaenus (Mascarensia) australiensis Franz, male. Left hind leg in posterior view (101); metatrochantero-femoral articulation (102). Abbreviations: cx3, metacoxa; fe3, metafemur; tr3, metatrochanter.

FIGURES 97–100. Scydmaenus (Mascarensia) australiensis Franz, male. Mouthparts in ventral view (97); distal region of right antenna in dorsal view (98); pterothorax and abdomen in ventral view (99); apex of left elytron in dorsal view (100). Abbreviations: aest3, metanepisternum; amvp, anterior metaventral process; a5‒11, antennomere 5‒11; bst, basistipes; cd, cardo; gal, galea; hyr, hypostomal ridge; lac, lacinia; lp, labial palp; mn, mentum; mst, mediostipes; msvp, mesoventral process; mtvp, metaventral process; plb, prelabium; ppf, palpifer; pyg, pygidium; sIII‒VIII, sternite III‒VIII; smnl, submental lobe.