Metopiasini
Raffray, 1904
Genus Guides
1Metopiasini is a tribe of minute rove beetles (Staphylinidae: Pselaphinae) comprising nine , eight of which are restricted to the Neotropical region. The tribe is suspected to be myrmecophilous, though direct associations remain unconfirmed. Members exhibit morphological traits consistent with subterranean or litter-dwelling habits, including reduced and elongated appendages. The genus Metopiellus, distributed from Colombia to Argentina, was recently recorded from Ecuador for the first time with two new described from Amazonian and montane cloud forest .
Pronunciation
How to pronounce Metopiasini: /mɛtoʊpiəˈsaɪni/
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Identification
The tribe can be recognized by the following combination of characters: second antennomere much longer than the third; protibia carinated anteromedially; metacoxae contiguous or nearly so; pronotum without sharp spines on the lateral edge. These traits are particularly diagnostic for the Metopiellus. Reduced and elongated appendages are common across the tribe, potentially reflecting adaptations to dimly lit microhabitats.
Habitat
Forest-floor leaf litter in tropical . Specimens have been collected from Amazonian lowland rainforest and montane cloud forest. One has been recorded from caves, suggesting for subterranean environments.
Distribution
Primarily Neotropical. Eight of nine are restricted to this region. The genus Metopiellus ranges from Colombia to Argentina, with confirmed records from Ecuador (eastern Amazonian provinces of Napo and Orellana; western Pichincha Province in montane cloud forest).
Host Associations
- ants - suspected myrmecophilySuspected based on morphological traits and early unconfirmed records; direct associations have not been repeatedly documented
Behavior
Suspected myrmecophily based on and sparse historical records, though this remains unconfirmed. Possible subterranean or hypogeal tendencies inferred from reduced , elongated appendages, and one cave collection record.
More Details
Collection methods
Specimens are typically collected by sifting forest-floor leaf litter and extraction using Winkler apparatus.
Taxonomic note
The tribe was established by Raffray in 1904 and contains nine . Recent taxonomic work has described new from previously unsampled regions, such as the first Ecuadorian records of Metopiellus.