Brachythops

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Taxonomy

Family: Tenthredinidae
Family common name: common sawflies
Subfamily: Selandriinae
Tribe: Selandriini
Genus: Brachythops Curtis, 1839
Subgenera: none

Background

The Tenthredinidae are the most species-rich family and are found throughout the world, in all continents but Antarctica. They are known as the “common sawflies.” They can generally be recognized by a cylindrical body and long, segmented antennae. Otherwise, they come in a variety of colors, sizes, and forms (Goulet 1992).

Sawflies in the Selandriinae subfamily are relatively small and slender. The range of Selandriinae is worldwide; it occurs on all continents except Antarctica (Goulet 1992). It is the most common and diverse group of tenthredinids in tropical regions, particularly in Central America, South America, and Southeast Asia (Smith 1969e). Selandriinae contains the only known sawflies that feed on non-vascular plants, specifically ferns (Smith et al. 2013). The subfamily can be distinguished from other subfamilies by wing venation (Goulet 1992).

Brachythops are about 5–6.5 mm in length and mostly black with an orange abdomen and short, stout antennae (Smith 1969e).

Diversity

There are four described extant species worldwide. Two species occur in North America (Taeger et al. 2010).

A key to Nearctic species is included in Smith 1969e.

Diagnostic characteristics

Subfamily characters

• fore wing vein Rs+M curved near intersection with vein Sc+R (Smith 1969e)
• fore wing vein M meeting Sc+R basal to intersection of Rs+M and Sc+R (Smith 1969e)
• fore wing vein 2r-m present (Goulet 1992)

Genus characters​

• clypeus margin straight or shallowly emarginated (Smith 1969e)
• malar space length twice the diameter of the front ocellus (Smith 1969e)
• occipital ridge absent (Smith 1969e)
• pedicel as long as wide (Smith 1969e)
• fore wing cell 1M slightly narrowed at apex; veins M and m-cu not parallel (Smith 1969e)
• fore wing anal crossvein absent (Smith 1969e)
• the intersection of fore wing veins M and M+Cu1 widely separated from intersection M and cu-a (Goulet 1992)
• hind wing vein 1r-m intersecting vein Sc+R (Goulet 1992)
• tergite 1 wide medially, membranous area narrow (Goulet 1992)
• mesepisternum with upside-down V-shaped furrow dorsally (Goulet 1992)
• tarsal claw with small inner tooth (Smith 1969e)

May be confused with

Brachythops can be confused with similar species in the subfamily Selandriinae. It can be distinguished from most other genera by the upside-down V-shaped furrow on the mesepisternum (Goulet 1992).

Exotic pest species of concern

none

Host associations

In North America, Brachythops feeds on Carex spp. (sedge) (Smith 1969e).

Life history

unknown

Distribution

World: This genus is Holarctic and has a range encompassing North America, central and northern Europe, eastern Russia, and China (Wei et al. 2006, Lelej and Taeger 2007, Taeger et al. 2010).

North America: Brachythops has a northern distribution and is found in Alaska, Yukon Territory, and Northwest Territories, and south through Canada into Colorado, Wisconsin, and New York in the United States (Smith 1969e).

Map data from: GBIF.org (29 October 2019) GBIF Occurrence Download Brachythops

Details about data used for maps can be found here.