Synonyms and other taxonomic changes
as subfamily Acridinae by Krauss in 1890, based on family Acrididae MacLeay 1821
Truxalides Serville 1839
as family Truxalidae by Burmeister 1840
as subfamily Tryxalinae by Krauss in 1890
as subfamily Truxalinae by McNeill in 1897.
tribe Hyalopterygini Brunner von Wattenwyl 1893
as subfamily Hyalopteryxinae by Dirsh in 1975
Explanation of Names
The common name is based on the fact that included species lack the mechanisms for making sound that are found in Oedipodinae and Gomphocerinae. However, the name is somewhat inaccurate, since many species can produce sound. Some species make fairly loud, often metallic sounds when they fly, and some species produce stridulation sounds, apparently by rubbing legs and/or wings together.
Numbers
One genus and one species in North America
(1), more diverse in tropics.
Remarks
As currently defined and with ranking levels used in the Orthoptera Species File, this subfamily is a catch-all for a number of dubiously related members of family Acrididae that don't fit comfortably into other groups for one reason or another.
In recent treatments based on morphological and molecular characteristics, the subfamily Acridinae is often limited to the small (entirely?) Old World tribe Acridini (=Truxalini), which includes only a few very closely similar genera, such as Acrida, Acridarachnea, Chromotruxalis, Glyphoclonus, Truxalis, Yendia, etc. The other genera and species placed in Acridinae (including most of those listed as tribe Acridini in the Orthoptera Species File) don't even look much like the above listed, and probably all belong to other subfamilies such as Oedipodinae, Gomphocerinae, or to their own unique small subfamilies.
American species mostly are placed in the tribe Hyalopterygini (sometimes called subfamily Hyalopteryginae), and are not very closely related to, nor even very similar to the Old World tribe Acridini. It seems probable that they should be placed as a specialized tribe within the subfamily Gomphocerinae (which they are much more like), or perhaps represent a distinct subfamily, which has [mostly] lost the stridulatory file on the hind femur.
The genus Achurum should probably also be placed in the tribe Hyalopterygini, as it seems closely related to certain member genera, including Metaleptea.
The genus
Stethophyma is another of those that doesn't fit. It is classed as Oedipodinae here. In nearly all world treatments of Grasshoppers (i.e.
Fauna Europaea), this genus (along with close relatives) is placed in that subfamily, and based on most morphological and apparently all molecular studies to date it belongs within the Oedipodinae. However, these species "look" like over-sized Slant-Faced Grasshoppers due to their coloration, smooth body, somewhat slanted face. The included species favor moist environments (thus - probably - the appearance). In the Orthoptera Species File, the genus was until recently included in the tribe Parapleurini within the subfamily Acridinae. Recently the tribe has been moved to the Oedipodinae there too.
On the flip side, there is a trend by some authors (who find distinguishing between the groups problematic) to put the Acridinae, Oedipodinae, Gomphocerinae, and others into just one single large subfamily, which bears the name Acridinae.
See Also
Gomphocerinae - (Stridulating) Slant-faced Grasshoppers
Oedipodinae - Band-winged Grasshoppers
Print References
Jago, N.D. 1996. Song, Sex and Synonymy: the Palaearctic Genus Acrida Linnaeus (Orthoptera, Acrididae, Acridinae) and Synonymy of the Subfamily Truxalinae under the Subfamily Acridinae. Journal of Orthoptera Research 5:125–129.
