Megalopinus

Eichelbaum, 1915

Species Guides

Megalopinus is a of rove beetles representing the sole genus in the Megalopsidiinae. The genus is characterized by large , with distinct di- or trisegmented clubs, a 5-5-5 tarsal formula, and unique elongated processes at the margin of the . Over 430 are known from the New World, with additional diversity in the Oriental region including a fossil species from Burmese amber. Four species occur in North America: M. caelatus, M. punctatus, M. rufipes, and M. lingafelteri.

Megalopinus rufipes by no rights reserved, uploaded by Lyn Roueche. Used under a CC0 license.

Megalopinus rufipes by (c) Zachary Dankowicz, some rights reserved (CC BY), uploaded by Zachary Dankowicz. Used under a CC-BY license.

Pronunciation

How to pronounce Megalopinus: /ˌmɛɡəloʊˈpaɪnəs/

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Identification

Distinguished from other Staphylinidae by the combination of large and distinctly clubbed with two or three segments forming the club. The elongated processes on the margin of the are unique to this within the . The 5-5-5 tarsal formula separates it from many other rove beetle genera with different tarsal segment counts. Within Megalopsidiinae, Megalopinus is the only genus, so -level characters confirm genus identity.

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Habitat

Found in decaying trees and fungus-infested logs. Specific microhabitat preferences within these substrates have not been detailed in available literature.

Distribution

Widespread across the New World with over 430 described . Four species in North America: Megalopinus caelatus (widespread), M. punctatus, M. rufipes, and M. lingafelteri (described 2023). Present in the Oriental region with 74 extant species plus one fossil species (M. extinctus from Burmese amber). Documented from Madagascar (M. puthzi, M. lemur, M. heissi), Australia (Queensland, New South Wales), and Colombia (Parque Nacional Natural Serranía de Chiribiquete).

More Details

Taxonomic uniqueness

Megalopinus is the sole in the Megalopsidiinae, making it taxonomically isolated within Staphylinidae. This phylogenetic distinctiveness has been supported by morphological and molecular studies.

Sperm pump morphology

The sperm pump, a structure in the male , has been reported in Megalopsidiinae for the first time in recent taxonomic studies. This structure was previously unknown in this and its presence has implications for understanding the evolution of internal genitalia in rove beetles.

Species discovery rate

The shows high with over 430 New World described, yet new species continue to be described regularly (e.g., M. lingafelteri in 2023, M. puthzi from Madagascar, M. casuarius from Australia), suggesting substantial undescribed diversity remains.