Metrodorinae, Bolivar, 1887

Cadena-Castañeda, Oscar J., Quintana-Arias, Ronald Fernando, Infante, Ivette Coque, Silva, Daniela Santos Martins & Tavares, Gustavo Costa, 2025, Studies on pygmy grasshoppers: On the current Metrodorinae sensu lato classification (Orthoptera: Tetrigidae) with emphasis on American and Malagasy taxa, Zootaxa 5597 (1), pp. 1-265 : 243

About Metrodorinae s. str.

According to the morphological and comparative studies conducted in this contribution, a new scheme for the classification of the subfamily and its tribal organization is proposed, focusing primarily on American and Malagasy taxa. Taxa from Asia and Oceania will be the subject of future studies to complete the overview of this contribution. At the moment, American taxa are considered Metrodorinae s.s., as they share general characters that were mainly proposed since the time of Bolívar and remain constant, unlike taxa from the Old World.

An important contribution to the definition of the subfamily Metrodorinae was the work of Pavón-Gonzalo et al. (2012). There, an interesting morphological study was conducted to delimit the species Allotettix simoni (Bolívar, 1890) and Allotettix peruvianus ( Bolívar, 1887), with a detailed morphological description of the former, including the last nymphal instar. Additionally, they provided a molecular characterization and analysis of phylogenetic relationships, which resulted in Metrodorinae not being monophyletic; its diagnostic characters are homoplastic and cannot separate the subfamily from other established ones. Although the authors did not focus on phylogenetic relationship analysis, their findings shed light on the taxonomic challenges to be faced in the future. It is understandable that at the time of publication of that contribution, species identification was still complicated, as they pointed out in their article, and as also evidenced by our own experience at the beginning of our first contributions to Neotropical tetrigids ( Cadena-Castañeda & Cardona-Granda, 2015; Silva et al., 2019a).

To understand the impact of the contribution of Pavón-Gonzalo et al. (2012), it was necessary to analyze the taxa studied by them, which involved Tetrix ceperoi ( Bolívar, 1887), Tetrix depressa Brisout de Barneville, 1848 (in 2012, this species was still included in Depressotetrix Karaman, 1960 ), Paratettix meridionalis (Rambur, 1838) , Paratettix pullus Bolívar, 1887 ( Tetriginae ), Allotettix simoni and Metrodora sp. ( Metrodorinae ). The phylogenetic relationship of the taxa was interpreted as ( Allotettix ( Tetrix + Depressotetrix ) + ( Metrodora + Paratettix )). Here, we transferred Allotettix to the subfamily Tetriginae , which is supported by the Tetrigidae clade presented by Pavón-Gonzalo et al. (2012), and that would be a clade with taxa from Tetriginae except for Metrodora sp.

All the species studied by Pavón-Gonzalo et al. (2012) are distinguishable in the photographs of the tree ( Pavón-Gonzalo et al., 2012: 164), except Metrodora sp. , which is a crucial taxon as it represents a possible new species, identified within the type genus of Metrodorinae . So, verifying the identification of Metrodora sp. is essential. Unfortunately, there was no photograph of the specimen in the paper, and it was based on a single adult male specimen from “El Portachuelo,” Aragua, Venezuela. Attempts were made to trace the possible deposition of this single specimen in the Museo Nacional de Ciencias Naturales (MNCN), Spain, and the Museo del Instituto de Zoología Agrícola Francisco Fernández Yépez (MIZA), Venezuela. Still, it was not found in either of the two entomological collections (Mercedes París (MNCN) and José Clavijo (MIZA), pers. comm.). Contact was made with the papers’ authors, and a kind response was received from Mario García-París, who informed us that “unfortunately, there are no photographs of the specimen, and it should be in the entomological collection of Venezuela (MIZA).” This suggests that the sole specimen of Metrodora sp. is lost, leaving us with difficulty. Unfortunately, the identity of this important specimen cannot be verified, and likewise, the non-monophyly of Metrodorinae cannot be confirmed either.

As mentioned before, identifying Neotropical tetrigids is still not easy. When Pavón-Gonzalo et al. (2012) conducted their research, it was even more challenging due to the limited bibliographic and photographic information available back then. Nowadays, significant contributions have been made, refining the taxonomy of American tetrigids further, and much bibliographic and photographic information can be accessed through the internet, available on platforms like OSF, or with the assistance and availability of curators from various entomological collections. As well-known and as discussed in this contribution and others, many morphological convergences are observed in Tetrigidae , and genera from different subfamilies can be confused or misidentified, exacerbated by the poor descriptions of many taxa. This could possibly have occurred in the identification of Metrodora sp. ( Pavón-Gonzalo et al., 2012); it might have been misidentified with a species of Tetriginae present in northern South America (between Panama and St. Vincent Island), such as Micronotus quadriundulatus (Redtenbacher, 1892) (see Cadena-Castañeda et al., 2021), which superficially could be confused with Metrodora s. l. This hypothesis could explain the relationship between species of Paratettix with Metrodora sp. nov. in the phylogenetic hypothesis by Pavón-Gonzalo et al. (2012).