Macrelmis

Motschulsky, 1859

Species Guides

Macrelmis is a of riffle beetles in the Elmidae, first described by Motschulsky in 1859. The genus contains at least three described in North America (M. moesta, M. shoemakei, M. texana) and additional species in South America, including three newly described from southeastern Brazil. Species are organized into ten defined species groups based on morphological characteristics. Larval stages have been described for some species, including M. aequalis from Argentina and M. isis.

Macrelmis shepardi by (c) Matthew Pintar, some rights reserved (CC BY), uploaded by Matthew Pintar. Used under a CC-BY license.

Macrelmis texana by (c) Justin Williams, some rights reserved (CC BY), uploaded by Justin Williams. Used under a CC-BY license.

Pronunciation

How to pronounce Macrelmis: //məˈkrɛl.mɪs//

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Identification

Macrelmis can be distinguished from related by features of the male genitalia, which form the basis for group definitions. The genus has been divided into ten species groups: aristeae, celsa, isus, granigera, milleri, striata, alea, amazonica, grandis, and jureceki. Larvae possess morphological characteristics typical of Elmidae but differ from the related genus Austrelmis in specific larval traits.

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Habitat

As members of the Elmidae (riffle beetles), in this inhabit running water environments. Larvae are aquatic and occur in lotic systems.

Distribution

The has a Neotropical distribution. North American records include at least three . In South America, species occur in southeastern Brazil (Rio de Janeiro, Minas Gerais, São Paulo states) and Argentina. GBIF records indicate presence across multiple departments in Colombia including Valle del Cauca, Antioquia region, and other areas.

Life Cycle

Mature larvae have been described for M. aequalis and M. isis. Larvae are aquatic and represent the primary feeding and growth stage before and as .

Similar Taxa

AustrelmisLarvae of Austrelmis and Macrelmis have been compared in morphological studies; both belong to Elmidae but differ in specific larval characteristics.

More Details

Species Groups

The has been reorganized into ten groups based on male : six redefined groups (aristeae, celsa, isus, granigera, milleri, striata) and four newly designated groups (alea, amazonica, grandis, jureceki).

Taxonomic History

The was first established by Motschulsky in 1859. Recent taxonomic work has focused on defining groups and describing new species from previously undersampled regions in South America.