Metacanthops Agudelo & Maldaner, 2019

Agudelo, Antonio A., Maldaner, Caroline & Rafael, José A., 2019, Dry leaf or twig mantis? A new genus and species of Acanthopidae with sexually dimorphic cryptic strategies (Insecta: Mantodea), Zootaxa 4560 (2), pp. 331-344 : 332-334

Metacanthops Agudelo & Maldaner gen. n.

Type species: Acanthops amazonica Beier, 1930

Diagnosis: Male habitus similar to that of Metilia , but entirely brown. Body length 23–35 mm. Males resembling a dry leaf, whereas females resemble a twig. Eyes slightly conical, with a small, apical wart. Vertex with arched apex, higher than eyes, and tuberculated in females. Head and pronotum smooth in males, with multiple tubercles in females. Prothoracic femora with 6 posteroventral spines, rarely with 5 or 7 on one femur. Prothoracic tibiae with 20–21 posteroventral spines with darkened apex, and 15–17 anteroventral spines. Mesothoracic wings shorter than metathoracic ones at resting, both are longer than abdomen in males but shorter in females, costal vein sinuous and excavated in the male. Lateral abdominal expansions of males of moderate size, in general, both sexes lack prominent lobes. Cerci cylindrical, distal cercomere conical, with a concave area dorsally.

Etymology: Metacanthops is a name with an intentionally ambiguous origin, resulting from the fusion of the Greek prefix meta = µετά, meaning beyond, and Acanthops , genus to which the species was initially assigned. The generic epithet also results from the fusion of “ Met ” (in reference to Metilia ), and Acanthops .

Remarks. Metacanthops differs from Metilia in having uniformly brown forewings, whereas the same in Metilia vary from dark green to yellow. However, it is in the head where conspicuous differences between Metacanthops and Metilia , and between them and Acanthops can be observed ( Figs. 13–22 ). For instance, the compound eyes of Metacanthops are only slightly conical and bear a small apical wart, whereas the same in Metilia and Acanthops are strongly conical with a more developed apical wart; the vertex of Metacanthops rises above the compound eyes, in the males it has distinct undulations in its central area and conspicuous juxtaocular process in females ( Figs. 14–17 ), whereas in Metilia and Acanthops these features are missing. Metacanthops has a robust and tuberculated pronotum, but in Metilia the same is relatively narrower and smooth ( Figs. 18, 19 ). The number of forefemoral posteroventral spines apparently constitutes a good diagnostic character in this case, as we consistently found 6 spines in all studied specimens of Metacanthops (however, in few rare cases some specimens have 5 or 7 in only one of their prothoracic legs), whereas we consistently found 7 forefemoral posteroventral spines across all specimens of Metilia (unpublished data). In addition, the margins of tergites V and VI are slightly prominent and rectangular in Metacanthops, whereas in Metilia they are dilated, semicircular or subtriangular.

The reliability of certain characters to separate acanthopid genera, such as vertex features, wing shape, abdominal appendages and, particularly, the number of forefemoral spines, have been a matter of controversy ( Chopard 1916; Giglio-Tos 1927; Rehn 1935; Terra 1995; Roy 2002). Chopard (1916) considered that the diagnostic characters of Plesiacanthops , Metilia , Decimiana , were all of little relevance for making such distinction, and thus he considered these genera merely as "subdivisions" of Acanthops . However, Giglio-Tos (1927) and Rehn (1935) considered that those characters were valid because they are commonly used at genuslevel in other mantodean taxa. Roy (2002) recently revisited this issue and suggested that the differentiation between Metilia and Acanthops cannot be justified based on the number of forefemoral posteroventral spines. For instance, he argued that Acanthops tuberculata has 7 posteroventral spines, unlike the rest of species in the genus with only 6 spines, whereas A. amazonica (which normally presents 6, but males sometimes having 5 or 8 in either forefemur) should be transferred to Metilia , whose species also have 7 spines. Although we agree with Roy (2002) in that amazonica is not a member of Acanthops , the newly available evidence suggest that its placement among Metilia should be reconsidered. Accordingly, we now formally transfer Acanthops amazonica Beier, 1930 to Metacanthops.

Figures

FIGURES 13–22. Summary of key morphological features to distinguish Acanthops and Metilia from Metacanthops: 13, head of Acanthops erosula, female (laterofrontal view); 14, head of Metilia sp., female (laterofrontal view); 15, Head of Metacanthops fuscum n. sp., female (laterofrontal view); 16, head of Metilia sp., male (frontal view); 17, head of Metacanthops fuscum, male (frontal view); 18, pronotum of Metacanthops fuscum, female (dorsal view),19: pronotum of Metilia sp., female (dorsal view); 20, male phallic complex of Metilia sp.; 21: male phallic complex of Metacanthops fuscum n. sp; 22: male phallic complex of Metacanthops amazonica n. comb. Abbreviations: right epiphallus (rph); basisclerite (bscl); left epiphallus (lph); titillator (ti); pseudophallus (psph); hypophallus (hph); apophysis (apo). Scale bar = 1 mm.