Euconnus (Tetramelus) mauritiensis (Lhoste) Jałoszyński, 2024

Jałoszyński, Paweł, 2024, The ‘ curse of Horaeomorphus’ (almost) lifted. Revision of misplaced species from Madagascar, Comoros and Mascarenes (Coleoptera, Staphylinidae, Scydmaeninae), Zootaxa 5505 (1), pp. 1-96 : 80-82

Euconnus (Tetramelus) mauritiensis (Lhoste) , comb. n.

( Figs 304–305 )

Scydmaenus (Vinsoniana) mauritiensis Lhoste, 1956: 284 .

Horaeomorphus mauritiensis (Lhoste) ; Franz (1972): 6.

Remarks. The history of misidentification of this species is complicated and difficult to understand, and perfectly exemplifies the ‘ Horaeomorphus curse’. Lhoste (1956) described Scydmaenus mauritiensis based on six syntypes collected on 31.10.1954 by J. Vinson on Mt. Cocotte, Mauritius. His illustrations (figs 1–3, reproduced here in Figs 304–306 ) clearly show a stenichnine beetle (not Scydmaenini!) with an elongate pronotum broadest in front of base and bearing two pairs of antebasal pits, antennae with elongate proximal flagellomeres and distinctly delimited tetramerous clubs, and the aedeagus, which was not completely dissected from surrounding structures, because the illustrated dorsal wall with a transverse row of setae is most likely the tergite X, showed as it was an integral part of the median lobe. All hitherto known species of Horaeomorphus have an uneven number of antebasal pronotal pits (three or five) and gradually broadening antennae, and for these reasons this species cannot belong in Horaeomorphus . The illustrated aedeagus is also clearly different from the form of the male copulatory organ typical of Horaeomorphus .

Despite these features, Franz (1972) transferred Scydmaenus mauritiensis Lhoste to Horaeomorphus and ‘redescribed’ it. He mentions “4 leider durchwegs sehr stark beschädigte Exemplare (♀♀)” (i.e., “4 unfortunately very badly damaged specimens (♀♀)”) examined for his ‘redescription’, collected by J. Vinson on 31.10.1954 on Mt. Cocotte. Franz did not disclose a source or depository of these specimens. His ‘redescription’ fully agrees with the original description, and the aedeagus is not illustrated, but described in reference to the Lhoste’s figure. Later, Franz (1986b) again treated this species, but this time he stated that the type specimens were not found neither in Muséum National d'Histoire Naturelle, Paris nor in Natural History Museum, London. Interestingly, he mentions that he had received one specimen from L. Gomy, which belonged in the original type series. This specimen, of an unspecified sex, according to Franz (1986b) bears a label “ Mauritius Mt. Cocotte 31.X.1954 J. Vinson”, which indeed agrees with the Lhoste’s (1956) description. Moreover, Franz (1986b) designated this single specimen as a lectotype and deposited it in his private collection. However, he again ‘redescribes’ this species, as Horaeomorphus mauritiensis , but not using the lectotype for this purpose. Instead, he simply cites verbatim the entire Lhoste’s description in French and reproduces the Lhoste’s illustrations ( Franz 1986b), as if no specimens were available.

The ‘lectotype’ in Franz Coll., currently at NHMW, indeed bears the possibly original label cited by Franz (1986b), and a red handwritten “ Lectotypus ” label. However, this specimen, illustrated here in Fig. 307 , is a true Horaeomorphus (female) with three antebasal pronotal pits. Without doubt, this specimen is different from what Lhoste (1956) illustrated, and what Franz (1972, 1986b) twice ‘redescribed’. Furthermore, in Natural History Museum, London, there are two “unfortunately very badly damaged specimens” bearing the same ‘original’ Vinson’s labels, both with only partly preserved remains of very likely the same true Horaeomorphus as the ‘lectotype’. One of them is a female lacking the head, the other one is a pterothorax with only one hind leg, elytra with the scutellar shield and abdomen of a male. I dissected the abdomen, and the aedeagus ( Figs 308–311 ) can be unambiguously recognized as representing a morphological form typical of Horaeomorphus , and it belongs to an undescribed species, very likely of a SE Asian or Australian origin.

To sum up, none of the specimens with the possibly original Vinson’s labels deposited at NHMW and in Natural History Museum, London is congeneric with Scydmaenus mauritiensis Lhoste , and the lectotype designation was not valid, because it was based on a misidentified specimen. It seems clear that these specimens have been mislabeled, but I was unable to figure out what had happened with the original Vinson’s specimens used by Lhoste to describe his species .

The aedeagus of Scydmaenus mauritiensis ( Fig. 306 ) is highly similar to that of Euconnus andasyensis , and although Lhoste illustrated the endophallus as symmetrical, while all Malagasy species of Tetramelus have asymmetrical endophallic sclerites, it is possible that the dark structures in his figure represent the combined most darkly sclerotized median proximal and distolateral endophallic structures, similar to those in Euconnus matsaboryi ( Fig. 268 ) or E. pellifer .

The transfer of Scydmaenus (Vinsoniana) mauritiensis Lhoste (‘ Horaeomorphus mauritiensis ’ of Franz) to Euconnus (Tetramelus) affects the status of the name Vinsoniana , which is not a junior synonym of Horaeomorphus , but a junior synonym of Tetramelus .

Figures

FIGURES 304–311. Euconnus (Tetramelus) mauritiensis (Lhoste), reproduced from Lhoste (1956) (304–305), and Horaeomorphus sp. mislabeled with original labels for syntypes of Scydmaenus mauritiensis Lhoste (307–311). Habitus in dorsal view (304); antenna (305); aedeagus in dorsal view (306); dorsal habitus of female from NHMW (307); aedeagus of a specimen from NHMUK in ventral (308, 310) and lateral (309, 311) views.

FIGURES 264–271. Euconnus (Tetramelus) matsaboryi Franz, holotype. Habitus in dorsal view (264); head in anterodorsal view (265); head and prothorax in lateral view (only bristles on head are shown) (266); antenna (267); aedeagus in ventral (268, 270) and lateral (269, 271) views.