Lachnopus

Schönherr, 1840

Lachnopus is a of broad-nosed (: Entiminae: Geonemini) comprising 73 described , making it the most diverse and widespread entimine weevil genus in the Caribbean Region. The genus was established by Schönherr in 1840 and has experienced unstable taxonomic placement, having been assigned to Cyphides, Barynotini, and currently Geonemini. Its validity as a distinct genus from Exophthalmus was confirmed by Franz (2012). Girón et al. (2018) recognized six species groups within the genus based on morphological phylogenetic analysis.

Lachnopus by (c) Heather Mazzaccaro, some rights reserved (CC BY), uploaded by Heather Mazzaccaro. Used under a CC-BY license.

Lachnopus by (c) Jared Shorma, some rights reserved (CC BY), uploaded by Jared Shorma. Used under a CC-BY license.

Identification

According to van Emden (1944), diagnostic characters include: weakly and evenly convex throughout; antennal extending to or slightly passing beyond middle of ; between eyes conspicuously narrower than surface of rostrum; not constricted posteriad of eyes; eyes only moderately convex; humeri only slightly wider than margin of ; unarmed; ventrally denticulate; and metatibial corbel lacking .

Images

Habitat

Island across the Caribbean, including orchid-associated environments and agricultural settings with citrus. Specific habitat data is limited for most .

Distribution

Caribbean Region, spanning the Lucayan Archipelago (The Bahamas and Turks and Caicos Islands), Greater Antilles, Cayman Islands, and Cozumel Island (Mexico). Some occur in Florida (L. argus, L. floridanus, L. hispidus).

Host Associations

Myrmecophila thomsoniana - Lachnopus vanessablockae collected on this Cayman banana orchid; first reported occurrence of Lachnopus as
Citrus - associatedLachnopus coffeae introduction to Grand Bahama associated with citrus transport from Puerto Rico; potential pest status

Behavior

Lachnopus vanessablockae has been observed as a of orchids, representing the first documented instance of in this . Lachnopus coffeae has been to new islands via human transport of citrus plants.

Ecological Role

of orchids (documented for L. vanessablockae on Myrmecophila thomsoniana); potential agricultural pest (L. coffeae on citrus).

Human Relevance

Lachnopus coffeae has been to Grand Bahama, likely via citrus transport from Puerto Rico, suggesting potential for economic impact on citrus . Some may serve as of ornamental orchids.

Similar Taxa

ExophthalmusHistorical confusion regarding distinctness from Lachnopus; separated by Franz (2012) based on morphological characters
IschionoplusPhylogenetic analysis places Ischionoplus as sister to the major Lachnopus clade; both belong to tribe Geonemini

More Details

Taxonomic instability

The placement of Lachnopus within Entiminae has shifted repeatedly: from Lacordaire's Cyphides (with Eustylini and Naupactini ) to Barynotini in van Emden (1944) and O'Brien and Wibmer (1982), now recognized as Geonemini.

Species groups

Girón et al. (2018) proposed six groups within Lachnopus, with three well-recognized subgroups in phylogenetic analysis: (1) widespread L. coffeae–L. lineicollis grade; (2) Hispaniolan L. proteus–L. mercator clade; (3) L. hispidus–L. guerinii clade (Cuba, Florida, Jamaica).

Phylogenetic status

Phylogenetic analysis of 61 morphological characters suggests Lachnopus may not be as currently circumscribed, though most fall within a major L. coffeae–L. guerinii clade.