Tetrigidae[1] is an ancient family in the orderOrthoptera,[2] which also includes similar families such as crickets, grasshoppers, and their allies. Species within the Tetrigidae are variously called groundhoppers,[3]pygmy grasshoppers,[4]pygmy devils[5] or (mostly historical) "grouse locusts".[6]
Diagnostic characteristics
A typical Tetrigid species that commonly inhabits arid banks of water bodies in Southern Africa. Lateral aspect, showing how the pronotum covers the hind wings. The vestigialtegmen is visible just above the anteriorcoxa.Tetrigidae Dorsal aspect. The same specimen from above. In both pictures note the unusually heavy structure of the posteriorfemur, and the correspondingly massive pulley-like femoro-tibial joint, similar to the anatomy of the Tridactylidae.
Tetrigidae are typically less than 20 mm in length and are recognizable by a long pronotum. This pronotum extends over the length of the abdomen, sometimes to the tip of the wings, and ends in a point.[4] In other Orthoptera, the pronotum is short and covers neither the abdomen nor the wings. Tetrigidae are generally cryptic in coloration.[7] Some species have enlarged pronota that mimicleaves, stones or twigs.[8][9] Other characteristics pygmy grasshoppers exhibit in comparison to other Orthoptera families are the lack of an arolium between the claws, the first thoracic sternite being modified into collar-like structure called sternomentum, a tarsal formula of 2-2-3, scaly fore wings, and developed hind wings.[10]
General biology
In temperate regions, Tetrigidae are generally found along streams and ponds, where they feed on algae and diatoms.[11] The North American species Paratettix aztecus and Paratettix mexicanus, for example, depend on aquatic primary production for between 80% and 100% of their diet.[12] Riparian species are capable of swimming on the surface of the water, and readily leap into the water when alarmed[9] Some species in the tribeScelimenini are fully aquatic and capable of swimming underwater.[10][11]
Like other Orthoptera, Tetrigidae have a hemimetabolous development, in which eggs hatch into nymphs. Unlike other temperate Orthoptera, however, temperate Tetrigidae generally overwinter as adults.[4]
Some subfamilies within the Tetrigidae, such as the Batrachideinae, are sometimes elevated to family rank besides the Tetrigidae.
Arulenus miae is a pygmy grasshopper species from the tropical mountainous rainforests of the Philippines. The species was firstly discovered in Facebook post.[5]
Paratettix aztecus eating algae
Etymology
Origin of the name of the family is not completely clear as there are different sources on its etymology. The name may be derived from Latin tetricus or taetricus, meaning harsh, sour, severe.[13] The name may also originate from the earlier name 'Tettigidae', based on Tettix (synonym of Tetrix), which was preoccupied by Tettigidae (synonym of Cicadidae).[14] Because of the preoccupation by the cicadas' family name, the second 't' in 'tt' was changed into 'r', resulting in the word Tetrigidae.
Subfamilies and Genera
Approximately 2,000 species have been described; according to the Orthoptera Species File[15] the following genera are included:
Tripetalocerinae was originally described by Bolívar in 1887[19] to gather all the Tetrigidae genera of the old world with widened antennae (e.g. Arulenus, Discotettix, Hirrius, Ophiotettix, Tripetalocera). This subfamily today includes only two species in two genera - Tripetalocera (with one species) from India and Borneo and Tripetaloceroides (with one species) from Vietnam and PR China. Members of the subfamily are characteristic within Tetrigidae by massive antennae built up of only eight segments (other Tetrigidae have usually 11-16, Batrachideinae 18-22).[20] Till recently,[20] the subfamily included two tribes - Tripetalocerini and Clinophaestini (including Clinophaestus and Birmana), but the later was moved to the subfamily Metrodorinae due to similarity to Ophiotettigini.[21]
^Ragge DR (1965). Grasshoppers, Crickets & Cockroaches of the British Isles. F Warne & Co, London. p. 299.
^ abcBorror DJ, Tripplehorn CA, Johnson NF (1989) An Introduction to the Study of Insects, 6th edition. Harcourt Brace College Publishers. New York. pg 213
^ abSkejo, Josip; Caballero, Joy Honezza S. (2016-01-21). "A hidden pygmy devil from the Philippines: Arulenus miae sp. nov. — a new species serendipitously discovered in an amateur Facebook post (Tetrigidae: Discotettiginae)". Zootaxa. 4067 (3): 393. doi:10.11646/zootaxa.4067.3.7. ISSN1175-5334. PMID27395882.
^Imms AD, rev. Richards OW & Davies RG (1970) A General Textbook of Entomology 9th Ed. Methuen 886 pp.
^ abGrimaldi D, Engel MS (2005) Evolution of the Insects. Cambridge University Press, Cambridge. pg 211
^Skejo, Josip (2017). Taxonomic revision of the pygmy devils (Tetrigidae: Discotettiginae) with online social media as a new tool for discovering hidden diversity. Zagreb: University of Zagreb, Faculty of Science, Department of Biology. pp. 1–246.
^ abPreston-Mafham K (1990) Grasshoppers and Mantids of the World. Facts of File, New York. pg 32
^ abcMuhammad, Amira Aqilah; Tan, Ming Kai; Abdullah, Nurul Ashikin; Azirun, Mohammad Sofian; Bhaskar, Dhaneesh; Skejo, Josip (2018-09-25). "An annotated catalogue of the pygmy grasshoppers of the tribe Scelimenini Bolívar, 1887 (Orthoptera: Tetrigidae) with two new Scelimena species from the Malay Peninsula and Sumatra". Zootaxa. 4485 (1): 1–70. doi:10.11646/zootaxa.4485.1.1. ISSN1175-5334. PMID30313773. S2CID52975589.
^Bastow, J. L.; Sabo, J. L.; Finlay, J. C.; Power, M. E. (2002). "A basal aquatic-terrestrial trophic link in rivers: algal subsidies via shore-dwelling grasshoppers". Oecologia. 131: 261–268.
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