Acanthomerosternoplini Tippmann 1955

Acanthomerosternoplini Tippmann, 1955

Acanthomerosternoplonini TIPPMANN, 1955:10; BOUCHARD et al., 2011:491; MONNÉ, 2018:499 (cat.; in syn.).

Scopadini VILLIERS, 1980:587; BOUCHARD et al., 2011:491; MONNÉ, 2018:499 (cat.; in syn.).

TIPPMANN (1955) erected the tribe “Acanthomerosternoplonini” to include his new genus Acanthomerosternoplon which included a single species, A. paradoxum (Fig. 1), described in the same work. Regarding the “Acanthomerosternoplonini”, Tippman stated that is was (translated): “Related with the tribe Cyrtinini, but pronotum with bifurcated lateral spine, profemora doubly spined, projection on prosternum lanceolate, pointing in the direction of the head.” Although he did not comment about the tarsal claws in the description of the tribe, he reported on the description of the genus (translated): “Tarsi same length, relatively short, 2 nd segment always having half-length of 1 st or 3 rd; claws almost as long as remaining three segments and strongly divergent.”

Evidently, Tippmann wrongly named the tarsomere V as “claws” and at the same time was talking about the shape of the true claws at the end of the sentence. Since the tarsal claws in A. paradoxum are divaricate and not divergent, they were mistakenly described as divergent.

Later, VILLIERS (1980) erected the tribe Scopadini, and correctly pointed out (translated): “Lacordaire does not seem to have seen the claws of Cyrtinus because it implies that they are divaricate while they are divergent. These are therefore all genera with divaricate claws that should be grouped into another tribe: Scopadini, nov. (Scopadus Pascoe, Omosarotes Pascoe, etc.)” Without doubt, André Villiers was correct since the claws in Cyrtinus LeConte, 1852 are divergent (Figs 4, 5), while they are divaricate in Scopadus (Fig. 3), and Omosarotes (Fig. 2).

Finally, JULIO & MONNÉ (2001) synonymized Acanthomerosternoplon with Omosarotes (translated): “Are proposed the transference of Scopadus nigripennis, Acanthomerosternoplon paradoxum and A. foxi for Omosarotes, thus making synonyms the genera Omosarotes Pascoe, 1860 and Acanthomerosternoplon Tippmann, 1955.” Accordingly, “Acanthomerosternoplonini” was considered a synonym of Cyrtinini since Omosarotes belonged to the latter.

BOUCHARD et al. (2011) correctly reported: “Acanthomerosternoplonini Tippmann, 1956: 10 [stem: Acanthomerosternopl-]. Type genus: Acanthomerosternoplon Tippmann, 1955 [syn. of Omosarotes Pascoe, 1860]. Comment: incorrect original stem formation, not in prevailing usage.”

Although the synonymy between Acanthomerosternoplon and Omosarotes is correct, Scopadini is a junior synonym of Acanthomerosternoplini. The best difference between Acanthomerosternoplini and Cyrtinini, as reported by VILLIERS (1980), is the shape of the tarsal claws.

Cyrtinini can be defined as proposed by VILLIERS (1980) (translated): “Head not retractile, flat or slightly sulcate between antennae. Mandibles very short. Eyes small, subdivided or divided into two separated lobes. Antennae slightly longer than body, from 10 to 11-segmented. Prothorax cylindrical, pronotum gibbous, inerme or tuberculate laterally. Elytra slightly longer than head + prothorax, depressed anteriorly, more or less tumid posteriorly. Legs moderately long, femora strongly pedunculate-clavate; metatarsomere I shorter than II-III together; claws divergent.” This description agrees well with that by DILLON & DILLON (1952). It includes: Cyrtinus, Decarthria Hope, 1834, Microloa Aurivillius, 1924, and Boricyrtinus Micheli, 2003. MICHELI (2003) did not comment about the tarsal claws in Boricyrtinus. However, it is possible to see that they are divergent (see BEZARK, 2018a). HOPE (1834) did not report the shape of the claws in the original description of Decarthria. However, according to GAHAN (1895) and VILLIERS (1980) they are divergent, which places the genus in Cyrtinini.

Acanthomerosternoplini differs from Cyrtinini as follows: eyes entire or nearly divided; antennae 11-segmented; tarsal claws divaricate. It includes: Omosarotes, Scopadus, and Sciocyrtinus Fisher, 1935. FISHER (1935) reported on Sciocyrtinus: “tarsal claws simple, divaricate.” However, the tarsal claws in Sciocyrtinus are divergent. Accordingly, the genus is maintained in Cyrtinini.

Before this work, Cyrtinini included 14 genera (TAVAKILIAN & CHEVILLOTTE, 2018). Neither AURIVILLIUS (1920) nor DILLON & DILLON (1952) mentioned the shape of the tarsal claws in Diastosphya Aurivillius, 1920. However, they appear to be divaricate in the holotype of D. bimaculata Dillon & Dillon, 1952 (see BEZARK, 2018b). As we did not examine specimens of this genus, it is provisionally kept in Cyrtinini. Enotocleptes Breuning, 1940 is also kept in Cyrtinini since we did not examine species of this genus and BREUNING (1940, 1951) provided contradictory information on the claws: BREUNING (1940) – “Die Klauen gesperrt”, suggesting that they are divergent; BREUNING (1951) – “crochets divariQués.” We also did not examine specimens of the following genera, in which the original description did not provide information on the shape of the claws: Gracilosphya Dillon & Dillon, 1952; Haplorhabdus Aurivillius, 1917; Leptocyrtinus Aurivillius, 1928; and Oloessa Pascoe, 1864. According to AURIVILLIUS (1913), the tarsal claws in Odontorhabdus Aurivillius, 1913 are divaricate; thus, after examination of specimens the genus should be transferred to Acanthomerosternoplini.