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Issue: Vol. 3 No. 2: 30 Apr. 2026
Type: Article
Published: 2026-04-30
DOI: 10.11646/jihs.3.2.8
Page range: 219-227
Abstract views: 36
PDF downloaded: 4

Closing a Half-Century Gap: The Discovery of the Male and Notes on Nymphal Morphology of Tetragonotum megacephalum Ruckes (Hemiptera: Pentatomidae: Discocephalinae: Discocephalini)

Laboratório de Sistemática e Diversidade de Artrópodes, Unidade Educacional Penedo, Campus Arapiraca, Universidade Federal de Alagoas, Penedo, AL, Brazil; PPG Diversidade Biológica e Conservação nos Trópicos, Universidade Federal de Alagoas, Maceió, AL, Brazil.
Laboratório de Sistemática e Diversidade de Artrópodes, Unidade Educacional Penedo, Campus Arapiraca, Universidade Federal de Alagoas, Penedo, AL, Brazil; PPG Diversidade Biológica e Conservação nos Trópicos, Universidade Federal de Alagoas, Maceió, AL, Brazil.
Museu de Zoologia, Universidade de São Paulo, São Paulo, SP, Brazil.
Museu de Zoologia, Universidade de São Paulo, São Paulo, SP, Brazil; Departamento de Ecologia e Biologia Evolutiva, ICAQF, Universidade Federal de São Paulo, Diadema, SP, Brazil.
Laboratório de Entomologia Sistemática, Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Laboratório de Entomologia Sistemática, Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Laboratório de Entomologia Sistemática, Departamento de Zoologia, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Discocephalini morphology Neotropic Pentatominae stink bug taxonomy

Abstract

Tetragonotum megacephalum Ruckes, 1965 (Pentatomidae: Discocephalinae) was described from a female collected in Bahia, Brazil. Since then, the genus and species have been cited a few times in the literature, including once in a dichotomous key to the broadheaded discocephalines genera, and another two times in checklists of pentatomoids of the Brazilian Caatinga. Based on an additional female and two male specimens, collected in the Caatinga, a seasonally dry forest restricted to northeastern Brazil, we describe the female and male genitalia of T. megacephalum, include notes on nymphal morphology, and provide a map with updated occurrence records. The male pygophore in Tetragonotum Ruckes is similar to other broadheaded discocephalines, such as Discocephala Laporte, Colpocarena Stål, Ischnopelta Stål, and Nigrisagitta Rosso and Campos, with a plate-like segment X beneath which the parameres are accommodated. Also, the pygophore posterolateral angles in T. megacephalum are projected and horizontal, and the phallus is laterally compressed. In the female genitalia, valvifers VIII are as wide as long, covering most of valvifers and laterotergites IX, and laterotergites VIII, laterotergites IX, and valvifers IX are fused to each other.

 

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