Family RHYPAROCHROMIDAE

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Family RHYPAROCHROMIDAE

Compiler and date details

15 February 2002

Introduction

The Rhyparochromidae or seed bugs (sensu Henry 1997) are a cosmopolitan family of lygaeoid bugs. Comprising two subfamilies, 14 tribes, 372 genera and 1,850 species (Slater & O'Donnell 1995; Henry 2009), the group is the most diverse pentatomomorphan family aside from the Pentatomidae. The Australian rhyparochromid fauna includes both subfamilies, 11 tribes, 75 genera and 190 species.

The Rhyparochromidae (= Megalonotinae) were first established as a suprageneric group by Amyot & Serville (1843). Summaries of the history of the classification of the Rhyparochromidae are given by Scudder (1957), Slater & Sweet (1961), Slater (1964a) and Slater & O'Donnell (1995).

Stål (1872, 1874—as Myodochina) established the classification of the rhyparochromids, recognising six tribal divisions: Boesaria, Cleradaria, Gonianotaria, Lethaearia, Myodocharia and Rhyparochromaria. His classification was primarily based on abdominal trichobothria. Breddin (1907) revised this classification based on the position of the abdominal spiracles. The comparative morphological works of Ashlock (1957; male genitalia), Slater & Hurlbutt (1957; hind wing) and Putschkov (1958; larvae) provided a major impetus for reclassification of the rhyparochromids.

Scudder (1957) reclassified the group, recognising four tribes: Drymini, Lethaeini, Stygnocorini (including Cleradini) and Rhyparochromini (including Gonianotina and Plociomerina. His classification was based on the relative position of the abdominal trichobothria and spiracles. Putschkov (1958) emphasised the value of the larval Y-shaped suture and highlighted problems in previous classifications. Slater & Sweet (1961) incorporated information from these characters systems in a reappraisal of the tribal classification, recognising the following tribes: Beosini, Cleradini, Drymini, Gonianotini, Lethaeini, Megalonotini, Myodochini and Plinthisini.

Sweet (1967) produced the landmark work on the tribal classification of the Rhyparochromidae. He recognised 14 tribes, including those of Slater & Sweet (1961) (aside from the polyphyletic Beosini), added two new tribes (Ozophorini and Udeocorini), accepted Ashlock's (1964) new tribes (Antillocorini and Targaremini), and resurrected the Phasmosomini, Stygnocorini and the nominotypical Rhyparochromini. Slater & Woodward (1982) added an additional tribe, the Lilliputicorini.

Henry (1997), in reclassifying the Lygaeoidea, established the Rhyparochromidae as a family, with two subfamilies. He elevated the plinthisines to subfamily ranking (also suggested by Schuh & Slater 1995) and recognised them as the sister-taxon to the remainder of the rhyparochromids (Rhyparochrominae sensu stricto). This classification is followed in this Catalogue.

The world fauna was catalogued by Slater (1964a) and Slater & O'Donnell (1995). Numerous regional taxonomic works exist that have general significance to rhyparochromid workers. Péricart's (1998a, 1998b) revision of the western Palaearctic fauna is the most comprehensive regional treatment. This work describes all life stages, ecology and. Other noteworthy regional works include: Kerzhner (1964; Palaearctic genera), Slater (1964b; South Africa) and Linnavuori (1978; Sudan). Scudder (1962a, 1962b, 1963, 1967, 1968, 1970a, 1970b, 1977, 1978, 1981) reviewed the status of type specimens of many rhyparochromid species.

Between 1950 and 1980 considerable work was produced on Australian Rhyparochromidae, primarily by Gross (1958, 1965), Malipatil (1977–1983), Scudder (1957–1981), Slater and co-workers (1964–1982), and Woodward and coworkers (1956–1988). Many of the suprageneric groups, such as the Plinthisinae, Cleradini, Lethaeini, Myodochini and Targaremini are described adequately. Generic endemicity is moderately high with 40% of the genera restricted to Australia—about three-quarters of the species are endemic. Slater (1975, 1976a, 1986) analysed the biogeography of the family and recognised circum-Antarctic and Indo-Pacific distribution patterns, as well as a distinct autochthonous component. Slater (1976b) and Malipatil (1979) described immature stages of several Australian rhyparochromids and Malipatil (1980) gave an account of chromosome variation in the males of numerous Australian species.

The Plinthisinae are a cosmopolitan subfamily comprising 3 genera and 111 species (Slater & O'Donnell 1995). The greatest diversity occurs in the Palaearctic (55 species) and Afrotropical (40) Regions. Slater & Sweet (1977) revised the Australian fauna of Plinthisus Stephens, describing all the known species, and assigning them to subgenera (P. (Isioscytus) Horváth, P. (Locutius) Distant and P. (Nanoplinthisus) Wagner). The plinthisine fauna of Australia includes 15 species, all but one of which are endemic—Plinthisus (Locutius) woodwardi Slater & Sweet also occurs in New Zealand. The majority of species are endemic to either semi-arid temperate areas or northern Western Australia. A few species are broadly distributed across States and territories. Slater (1975) and Slater & Sweet (1977) reported that the Australian Plinthisinae are represented by two elements: a temperate Bassian clade of flightless species that are closely related to the South African plinthisines and a northern, more tropical element, that has affinities with the Oriental fauna.

The Rhyparochrominae of the world comprise 369 genera and 1824 species (Table 10). The subfamily is represented in Australia by 74 genera and 175 species, with about 40% of the genera and 75% of the species endemic. Slater (1986) analysed the zoogeography of the tribes. Eleven of the currently accepted rhyparochromids tribes are represented in Australia, with only the Gonianotini (Holarctic), Megalonotini (mostly Palaearctic, Afrotropical and Oriental Regions) and Phasmosomini (Palaearctic Region) not represented. The greatest diversity in Australia occurs in the following tribes: Cleradini, Drymini, Lethaeini, Myodochini, Rhyparochromini and Udeocorini.

The Antillocorini is cosmopolitan in distribution and comprises 24 genera and 91 species (Slater 1986; Slater & O'Donnell 1995). Ashlock (1964) first recognised the group at suprageneric level. It is most diverse in the Neotropical Region and represented by no more than five genera in all the other zoogeographic regions. In Australia, Antillocorini is represented by three genera and five species. Botocudo Kirkaldy is broadly distributed (not in the Palaearctic Region) and represented in Australia by an endemic species, B. ornatulus (Bergroth), known only from tropical central Queensland. Lethaeaster Breddin is found in Malesia and Melanesia, and represented in Australia by L. anthocoroides Breddin, which is found in tropical north Queensland, Indonesia and Malaysia. Tomocoris Woodward is represented by three species along the east coast of Australia, and is also found in the Cook Islands. Slater (1983) reviewed the Australian members of the tribe and Schuh & Slater (1995) questioned its monophyly.

The Cleradini is mostly Indo-Pacific in distribution and comprises 20 genera and more than 50 species (Slater & O'Donnell 1995). The tribe is most diverse in Australia, there being 7 genera and 26 species, or about 40% of the world fauna; four of the genera and 23 species are endemic. Laticlerada Malipatil (5 species) and Paramahisa Malipatil (9) are the richest genera. Most species are found in the tropical regions of Queensland, although a few are broadly distributed across temperate Australia. Clerada apicornis Signoret, found in many parts of the world, is recorded from eastern Australia. Malipatil (1981) revised the Australian fauna and described many new taxa (4 genera and 16 species). Subsequently, Malipatil (1983) revised the world fauna and provided a cladistic analysis of the genera.

The Drymini is found primarily in the Eastern Hemisphere and is not indigenous in South America. The tribe comprises 56 genera and 280 species and is most diverse in the Palaearctic, Afrotropical and Oriental Regions (Slater 1986). Twelve genera and 19 species are present Australia, of which 5 genera and 16 species are endemic. The tribe is broadly distributed across Australia and the majority of species occur in Queensland (15 species). Three mainland species are also found in New Zealand (Grossander major (Gross), Paradrymus exilirostris Bergroth and Scolopostethus forticornis Gross), and Brentiscerus obscurus (Gross) occurs on Lord Howe Island. Gross (1965) described most Australian species. Slater (1975) discussed the zoogeography of the Drymini and hypothesised that drymines are adapted to shaded open woodlands and forest edges. Slater (1986) claimed that the distribution of the Australian Drymini is difficult to interpret because the paucity of knowledge of the Oriental fauna confounds biogeographic analysis.

The Lethaeini is a cosmopolitan tribe comprising 35 genera and 153 species (Slater & O'Donnell 1995). The greatest diversity of taxa occurs in the tropical and subtropical parts of the Afrotropical, Oriental and Australian Regions (Slater 1986). The tribe is represented in Australia by 11 genera and 25 species, and most of the species and 7 genera are endemic. Slater (1975) reports that lethaeine distribution resembles that of the Plinthisinae, with south temperate (Coleocoris Gross, Carabocoris Gross, Exomyocara Slater & Woodward and Myocara Bergroth) and tropical (Neolethaeus Distant) components. The temperate component includes mostly flightless (coleopteroid) species with restricted distributions, particularly in Western Australia (four endemic species). Gross (1958) and Woodward (1962, 1968, 1980a, 1980b, 1981; Woodward & Malipatil 1977; Woodward & Slater 1962) described most of the Australian taxa. A number of new taxa are known to exist in Australian collections.

The Lilliputocorini is circumtropical in distribution and comprises the nominotypical genus, Lilliputicoris Slater and Woodward, and eight species (Slater 1986, Slater & O'Donnell 1995). In Australia, Lilliputicoris is represented by two species: L. punctatus (Woodward) is found in northern Australia and Papua New Guinea and L. terrareginae Slater & Woodward is restricted to tropical north Queensland.

The Myodochini is a cosmopolitan tribe of 73 genera and 322 species (Slater & O'Donnell 1995). Aside from the nominotypical tribe, this is the most speciose rhyparochromine tribe. Myodochine diversity is greatest in the Western Hemisphere (Slater 1986). They are relatively depauperate in Australia numbering 12 genera and 27 species, of which two genera and 13 species are endemic. The tribe has an Indo-Pacific distribution pattern and the majority of genera and some species are broadly distributed in the tropics of the Eastern Hemisphere. Nearly all the Australian species are found in tropical coastal Queensland; a south temperate component is lacking. Malipatil (1978) revised the myodochines of the Australian Region, describing eight new genera and 12 new species. Harrington (1980) revised the Myodochini of the world and proposed many new synonymies and new combinations. She also provided a cladistic and biogeographic analysis of genera and argued that the radiation of the tribe was post-Gondwanan.

The Ozophorini is a speciose tribe of 24 genera and 175 species (Slater & O'Donnell 1995), which is most diverse in the Neotropical and Oriental Regions (Slater 1986; Chen & Ashlock 1987; Schuh & Slater 1995). Ozophorini is represented in Australia by two genera (Bedunia Stål and Ethaltomarus Scudder) and five species, three of which are endemic. Slater & Woodward (1974) described the Ethaltomarus species. Slater (1975) regarded the Ozophorini to be a recent addition to the Australian fauna.

The Rhyparochromini is the most diverse tribe of Rhyparochrominae and presently comprises 39 genera and 370 species. The group is found in all major zoogeographic regions aside from the Neotropical Region, but is most diverse in the Afrotropical, Palaearctic and Oriental Regions. The tribe is poorly represented in Australia, there being 7 genera and 30 species; all seven genera are found extralimitally but species endemicity is high (67%). Most genera are also found in Melanesia and the Oriental Region. The most diverse genera are Dieuches Dohrn (13 species), Elasmolomus Stål (5 species) and Stizocephalus Eyles (7 species). Many species are broadly distributed across continental Australia, and some of these are also found to the north of Australia. Stizocephalus has a predominantly south temperate distribution. The most significant works relevant to the Australian fauna are Gross & Scudder (1963), Eyles (1970, 1973) and Scudder (1975).

The Stygnocorini is a moderate-sized tribe of 16 genera and 73 species. It is absent from the Western Hemisphere and is most diverse in the Afrotropical and Palaearctic Regions. In Australia, the tribe is represented by an endemic species, Tasmanicola truganinae Slater & Sweet, which is broadly distributed from the Atherton Tableland to Tasmania. Slater (1986) argued that this species has affinities with taxa in montane South Africa and New Zealand.

The Targaremini is restricted to the Australian Region and comprises 23 genera and 57 species (Slater 1986; Slater & O'Donnell 1995). Centres of endemism of targaremines exist in eastern Australia, New Zealand, New Caledonia and Vanuatu (Slater 1986). In Australia the fauna is represented by six genera and nine species, with almost half of the genera and most of the species being endemic. Slater (1976a) reported that the Australian members of the tribe are associated with mesic forest (including Nothofagus forests) and woodland habitat. The majority of species are flightless and Malipatil (1977) and Slater (1986) have alternatively suggested dispersalist and vicariant explanations for their distribution. Genera are found jointly in Australia and New Caledonia (Hebrolethaeus Scudder and Lachnophoroides Distant) and Australia and New Zealand (Geratarma Malipatil). Woodward (1953, 1956, 1978, 1986) described the majority of the Australian species. The New Zealand Targaremini were revised by Eyles (1967) and Malipatil (1977).

The Udeocorini comprises 14 genera and more than 30 species (Slater & O'Donnell 1995) and is restricted to the Australian (Australia, New Zealand and Timor) and Neotropical Regions. Slater (1986) argued that udeocorines have a Gondwanan origin. The udeocorine fauna of Australia is composed of 10 genera and 24 species, and most of the taxa are endemic. Slater (1975) argued that, within Australia, the Udeocorini is an ancient dry-adapted group, that has a predominantly south temperate distribution. Udeocorines are also represented in tropical Australia and both Telocoris species also co-occur in Timor. Daerlac Signoret (6 species) and Euander Stål (4 species) are the most diverse genera. Gross (1962) revised the Australian fauna and described the majority of taxa. Slater et al. (2009) revised the Australian genus Laryngodus Herrich-Schaeffer, including the description of two new species.

The habitats and habits of rhyparochromids are relatively well known. Sweet (2000) summarised their biology and documented the few species of occasional economic importance. Other key references, particularly those concerned with feeding behaviour, include Eyles (1963, 1964) and Sweet (1960, 1964a, 1964b)). The majority of rhyparochomids are ground-dwelling seed-predators, feeding mostly on fallen mature seeds (Schuh & Slater 1995). The preponderance of wing polymorphism in epigaeic rhyparochromids is thought to be linked to permanency of habitat. Many species are flightless and wing-shortening is a common condition amongst members of the Plinthisinae, Lethaeini, Targaremini and Udeocorini (Slater 1975; Malipatil 1977).

The host associations of most species are unknown and the degree of host-specificity is poorly understood. Sweet (1960) established that many North American species can be reared on sunflower seeds. Numerous species have been collected in the 'seed-shadow' of plants. Slater (1975) reported a number of Australian rhyparochromids in association with the fallen seeds of plant species in heathland habitats (often Myrtaceae, Fabaceae and Epacridaceae). He also indicated that species assemblages of rhyparochromids (Antillocorini, Drymini, Lethaeini, Ozophorini and Udeocorini) are sometimes associated with the same host plant.

Malipatil (1979) examined the biology of a number of Australian species of Myodochini, Rhyparochromini, Udeocorini and Lethaeini. He made observations on wing polymorphism, mimicry, predation and parasitism, host plants, feeding habits and ovipositional behaviour.

Members of the Cleradini are haematophagous, feeding on the blood of vertebrates (Harrington 1980; Malipatil 1983; Schuh & Slater 1995). They have been collected mostly from the nests of birds, marsupials and rodents (Sweet 1967, Harrington 1988, Malipatil 1981). In Australia, Laticlerada laticollis Horváth and L. monteithi Malipatil are known from the nests of possums (Bergroth 1914, Wilton-Smith 1978). The introduced species, Clerada apicocornis, is known to occasionally feed on human beings (Illingworth 1917) and is implicated in the transmission of Chagas' disease in South America (Malipatil 1981).

Aside from the Cleradini, rhyparochromids are remarkably homogeneous in their biology. Exceptions include some Australian myodochine and udeocorine species which are found 'up-on-plants' (Malipatil 1979). There are also reports of occasional arthropod-feeding by rhyparochromids (Slater & Carayon 1963) although no such records exist for Australia.

Diagnosis

Rhyarochromids are small, dull insects, that are either brown or mottled with dark and pale contrasting markings. The head usually bears trichobothria. Ocelli are present. The antennae and labium are 4-segmented. The fore femora are often swollen and often armed on the ventral surface with strong spines. Most species have a fused curving suture between sterna IV and V, terminating at the trichobothrial furrow (not in Plinthisini). The male vesica has a helicoid process. (Sweet 1967; Schuh & Slater 1995; Henry 1995)

Published	As part of group	Action Date	Action Type	Compiler(s)
15-Aug-2012		15-Aug-2012	MODIFIED
		12-Feb-2010	(import)

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