FNZ 60 - Carabidae (Insecta: Coleoptera) - Introduction
Larochelle, A; Larivière, M-C 2007. Carabidae (Insecta: Coleoptera): synopsis of supraspecific taxa. Fauna of New Zealand 60, 188 pages.
( ISSN 0111-5383 (print), ; no. 60. ISBN 978-0-478-09394-0 (print), ). Published 21 Nov 2007
The family Carabidae (including tiger-beetles) is taxonomically diverse, with an estimated total of over 34,000 species in 1,927 genera (Lorenz, 2005). Carabids occupy most terrestrial habitats on nearly all continents. These beetles are abundant in the field and attract attention with their shape and coloration. They are mostly nocturnal and polyphagous predators (Larochelle, 1990) although some are diurnal or phytophagous. Most ground-beetles, in temperate zones at least, live at the surface of the ground, while some species live in the soil (e.g., Anillina), in caves (e.g., Trechini, Harpalini), or on the vegetation (e.g., Zolini, Lebiini). Most New Zealand genera are flightless, which makes their dispersal capacity somewhat limited and their populations morphologically varied, sometimes even aberrant. In 2001, Larochelle & Larivière’s Catalogue (Fauna of New Zealand 43) recorded 5 subfamilies, 20 tribes, 78 genera, and 424 species for the fauna, whereas the current work recognises 7 subfamilies, 21 tribes, 86 genera, and 461 species, comprised of 50 endemic (58 % of fauna), 17 native (20 %), and 19 adventive (22%) genera.
As a family, Carabidae exhibit a relatively high degree of morphological uniformity, making them suitable to study the ecophysiological adaptations required to cope with environmental demands. Being sensitive to their environment, they demonstrate a flexible set of responses to both abiotic and biotic factors. Carabids are commonly used as bioindicators (Larochelle & Larivière, 2003) to assess the biodiversity of ecosystems, indicate the impact of landscape changes, evaluate environmental health, predict the effect of climate changes, classify habitats for nature protection, characterise soil-nutrient status in forestry. They can also be used to control pest invertebrates (e.g., lepidopteran caterpillars). In the future, ground-beetles may become more commonly used in biological and integrated programs, e.g., as natural control agents of noxious invertebrates, especially soil insect pests, or control agents of weeds, especially their seeds.
This synopsis is aimed at systematists and identifiers. Its purpose is to provide for the first time a taxonomic review of all New Zealand supraspecific taxa of Carabidae, including: comparative descriptions for subfamilies, tribes, subtribes, genera, and subgenera; identification keys for subfamilies, tribes, and genera; habitus drawings, distributional and ecological information, and summaries of collecting techniques for all genera; the most relevant bibliographic references for all taxa; an updated checklist of species and a summary of all taxonomic changes since the publication of the catalogue by Larochelle & Larivière (2001). Furthermore, this first attempt at providing fully comparative descriptions for all taxa at each level of classification, is intended to facilitate identification and information retrieval for analysis (e.g., cladistics, ecomorphology, revisions of genera). Finally, the New Zealand carabid fauna is here presented within the context of the most recent developments in the higher classification of this group on a world basis.
This work is one more step in the authors’ goal of reaching an overall understanding of the New Zealand carabid fauna within a reasonable time frame and making relatively large amounts of information available for practical use by a wide range of end-users. The methodology is based on the concept of ‘practical taxonomy’ described by Darlington (1971), which aims to provide “a floor plan for more detailed taxonomic, ecological, zoogeographical, and evolutionary studies.”
The authors have temporarily put on hold their revisionary work on New Zealand carabid species, as started with the Harpalini (Larochelle & Larivière, 2005), in order to accelerate the treatment of the overall fauna and to fulfill a taxonomic wish expressed by many. For example, R.T. Bell (2002) in his book review of Larochelle & Larivière (2001) wrote: “I trust that it [the Catalogue] will be soon followed by a volume containing tribal and generic keys, opening the way for generic revisions and accelerating the study of this unique fauna.”
In addition to paper-based publications such as this one, the authors edit the New Zealand Carabidae website (http://www.landcareresearch.co.nz) which maintains up-to-date information on New Zealand carabids, including digital images, recent literature, and additions and corrections to previous publications.
Brief history of New Zealand carabid taxonomy
A more detailed account can be found in Larochelle & Larivière (2001); only supraspecific taxa are emphasised here.
The first endemic carabid genus to be described from New Zealand was Loxomerus Chaudoir, 1842. The describers of New Zealand’s endemic genera have been: Chaudoir (1842–1878, 4 genera), Blanchard (1843, 1 genus), Fairmaire (1843, 1 genus), White (1846, 2 genera), Bates (1867–1874, 4 genera), Laporte de Castelnau (1867, 2 genera), Putzeys (1868, 1 genus), Broun (1881–1910, 6 genera), Sharp (1886, 2 genera), Jeannel (1928–1938, 5 genera), Brookes (1932–1944, 2 genera), Britton (1940–1964, 9 genera), Rivalier (1963, 1 genus), Townsend (1971, 1 genus), Lindroth (1980, 1 genus), Moore (1980, 2 genera), Larochelle & Larivière (2005, 5 genera), and Johns (2007, 2 genera). The current monograph adds 3 new endemic genera to the fauna.
Taxonomic revisions were initiated by Jeannel (1937, Anillina; 1938 Amarotypini, Migadopini, Trechini). Tribes and genera revised afterwards have been: Broscini (Britton, 1949; Pawson et al., 2003b, Oregus); Bembidiini, except Tachyina (Lindroth, 1976, 1980; Moore 1980); Harpalini (Larochelle & Larivière, 2005), Pterostichini (Britton, 1940; Butcher, 1984, Holcaspis); Lebiini (Britton, 1941); Pentagonicini (Britton, 1941); cave-dwelling Trechini and Harpalini (Britton, 1958–1964).
Identification keys are rare, poorly developed, parsimoniously illustrated, scattered through the world literature, and sometimes written in foreign languages, e.g., French. Britton (1940) provided the first identification key to New Zealand tribes; his key is now outdated.
Klimaszewski & Watt (1997) published keys to subfamilies and tribes. Unfortunately, their keys have some difficulties and are outdated. The subfamilial nomenclature has changed (Scaritinae, Broscini = Trechinae, Broscini). The tribal nomenclature is now different (Cychrini = Pamborini; Migadopini = Migadopini + Amarotypini; Psydrini = Mecyclothoracini + Meonini + Tropopterini; Agonini = Platynini). Two of the characters they use (body pedunculation; position of scutellum relative to peduncle and elytral bases) are somewhat subjective and do not allow the assignment of numerous New Zealand genera to the correct subfamilies and tribes. The term pedunculate (with a peduncle), when referring to the body shape, is a loose concept especially difficult for identifiers to interpret, as it suggests any level of narrowing of the waist, either between the thorax and the abdomen, or at the level of the elytral bases. A more practical approach is taken in the current monograph to allow a more objective recognition of this attribute. Taxa considered to have a pedunculate body have the scutellum placed directly on a visible peduncle (between pronotum and elytra; Fig. 186) or placed partly between and above the elytral bases (Fig. 187). Taxa without a pedunculate body have the scutellum inserted entirely between elytral bases (Fig. 188). In their key to tribes, Klimaszewski & Watt use the number of paired supraorbital setiferous punctures to distinguish between Agonini (=Platynini) and Harpalini. Unfortunately this does not work for all taxa as some Ctenognathus species (Platynini) have only a single pair of supraorbital setiferous punctures like members of the tribe Harpalini. Furthermore, the recently introduced tribes Perigonini (genus Perigona) and Pseudomorphini (genus Adelotopus) have never been included in keys for New Zealand.
At the generic level, the first identification ‘table’ was provided by Broun (1893a) for the Feronidae (= Pterostichini), with the genera Rhytisternus, Trichosternus, Pterostichus, and Zeopoecilus. Matthews’ (1980) identification guide to the beetles of South Australia allows the identification of several of New Zealand’s native and adventive genera. However, a key to all described genera has not been available until now.
The history of carabid classification has been extensively discussed by Ball (1979), Bousquet & Larochelle (1993), Ball et al. (1998b), and Arndt et al. (2005). The classification presented by Arndt et al. (2005) takes into account the major changes brought about by recent scientific research, at the subfamily level only and it is followed here. The tribal classification used by Larochelle & Larivière (2001) and kept here, is based mostly on the classification in Erwin (1991) which still receives general acceptance from the scientific community. Table 1 offers a comparison between the higher classification used in the present work and in Larochelle & Larivière (2001).
The identification of New Zealand genera can be achieved by specialists or non-specialists using a combination of tools: habitus drawings, comparative descriptions, identification keys, supporting distributional and ecological information, and access to a reference (or synoptic) collection authoritatively identified by a carabid specialist. The New Zealand Arthropod Collection (NZAC, Landcare Research, Auckland) is the largest such authoritative reference collection, containing representatives of most New Zealand genera and species, including type specimens as well as homotypes (specimens compared with types) identified by renowned experts.
When identified to genus by a non-specialist, specimens can be sent to a specialist who will undertake an authoritative identification at the species level (Mayr & Ashlock, 1991). If attempted by non-specialists, species level identification in the context of a largely unrevised fauna like the New Zealand carabids (less than two-thirds having been described) has a high probability of being erroneous. To be absolutely certain of their identifications even specialists have to dissect male genitalia, whether groups have been recently revised (e.g., Harpalini) or not. Consequently, it is imperative that non-specialists always have their identifications confirmed by specialists.
Specimen-based information should never be published or databased unless a carabid specialist has confirmed the identity of genera and species involved.
Revisions and field surveys
Most taxonomic revisions published until now have been based mainly on type material or small collections made before the general national insect surveys of the 1960s and 1970s. More specialised intensive carabid inventories started only in the 1990s.
Considering the material currently contained in New Zealand entomological collections and museums, the authors predict a fauna much richer than currently known, likely to reach 800 species-group taxa, once specialised inventory techniques are employed and revisions of all tribes and genera are conducted.
Most New Zealand carabid genera are in need of revision or of further revision. This is indicated in the Note section provided under genera in the main text. Various factors have led to such assessment, e.g., monotypic genera that may be polytypic, genera in need of more detailed taxonomic work, genera potentially containing several conspecific entities, genera needing further clarification in the light of overseas treatments, etc.
‘Hit-and-run taxonomy’ – isolated or random descriptions of new taxa – for groups badly needing thorough taxonomic revisions (most New Zealand tribes and genera) should be avoided as much as possible. This is a misguided action even when aimed at resolving tag-names for alleged conservation imperatives and for ‘iconic’ taxa. “The description of isolated new species in poorly known groups of animals is usually a handicap to subsequent workers”; “many more synonyms are created through isolated descriptions than through more substantial revisions” (Mayr & Ashlock, 1991). Isolated species descriptions are rendered even more problematic and frustrating to taxonomists and identifiers when not including illustrations of the male genitalia and comparative diagnostic characters against already described close relatives, and when not presented in the context of previously published revisions and identification keys. To be most relevant species-level taxonomic revisions for a largely undescribed fauna such as that of New Zealand should ideally be carried out at least at the generic level.
Comprehensive revisions can be done only with adequate material from all species of a genus and from all major New Zealand collections and museums. The material under study should be composed of sufficiently long series from the same populations for a proper assessment of intra- and interpopulational variability. Numerous samples from the periphery of the range of each hypothesised species are also essential to resolve the taxonomic limits of taxa. Finally, a number of geographic areas of New Zealand display high species diversity, extremely variable taxa, or aberrant forms, e.g., Whangarei (ND) to Thames (CL), Palmerston North (WI) to Nelson (NN), Picton (SD) and Blenheim (MB), the Canterbury Plains (NC, MC, SC) to the Mackennzie Country (MK). Such material should be given special attention and it is especially important for it to be considered within the wider taxonomic and biogeographic contexts so as not to confuse local variation with true speciation.