Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

FNZ 60 - Carabidae (Insecta: Coleoptera) - Methods and conventions

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
ZooBank: http://zoobank.org/References/842D820C-05B3-4072-B094-73070E640945

Methods and conventions

Materials

This synopsis is based on 15 years of laboratory research and extensive fieldwork carried out in over 1000 localities, an extensive survey of the world literature up to now, identification of carabids and recording of information associated with adult specimens from the following entomological museums and collections:

AMNZ Auckland Institute and Museum, Auckland, New Zealand.
CMNZ Canterbury Museum, Christchurch, New Zealand.
LUNZ Entomology Research Museum, Lincoln University, Lincoln, New Zealand.
MONZ Museum of New Zealand Te Papa Tongarewa, Wellington, New Zealand.
NZAC New Zealand Arthropod Collection, Landcare Research, Auckland, New Zealand.
OMNZ Otago Museum, Dunedin, New Zealand.
UCNZ Department of Zoology, University of Canterbury, Christchurch, New Zealand.

Collecting and preparation

Adult ground-beetles are generally collected using the following techniques (in order of decreasing importance): pitfall trapping; turning fallen trees, logs, pieces of wood, stones, moss carpets, and plant rosettes; raking the leaf litter; sifting the leaf litter and moss; sifting soil samples from the base of trees and the underside of big stones; lifting the loose bark of logs and fallen trees; dismantling logs and rotten stumps; breaking branches of fallen trees; digging at the base of plants; using Malaise traps, pan traps, and interception traps; using light traps or head-lamps at night; collecting in caves with head-lamps or baited traps; collecting at twilight on dunes and beaches; sweeping or beating the vegetation; fogging the canopy; pyrethrum spraying of the rotten bark of dead standing trees; smoking tree-stumps; sugaring trees; sifting fermented sawdust or garden compost; inspecting soil crevices and the tunnels of small vertebrates; raking loose gravel at the water’s edge; pouring water over the ground and treading the soil with feet; throwing dead leaves and fallen fern branches into the water; turning drift material along the seashore, lake shores, or stream banks.

Adult carabids often disappear from the ground surface in the summer; the only way to assess their abundance, breeding period, or overall life cycle is by quantitative pitfall trapping conducted over a period of at least one or two years.

Adults are best preserved dry. All life stages can be collected in 70–75% ethanol. If a molecular study is intended, adults as well as immatures can be kept in 95–100% ethanol.

All specimens should be labelled with the locality name (including area code: Crosby et al. 1976, 1998, and geographical coordinates such as latitude and longitude), collection date, collector’s name, and biological data (e.g., general habitat, microhabitat, behaviour).

Most features of the external morphology and the male genitalia can be viewed under an ordinary dissecting microscope. Although the examination of the male genitalia is not necessary to separate most genera, it may be useful in some cases.

Dissections can be performed as follows: Pinned specimens (individually or in batches) are warmed for 5–10 minutes in hot alcohol (70–75% ethanol). Once softened, each specimen is transferred to a cavity slide containing ethanol. A pair of fine forceps is used to extract the male genitalia from the abdomen. This is done under the microscope by inserting the forceps into the rear aperture, cutting through the lateral membranes that unite the last two terga and sterna, pulling out the aedeagus and associated genital ring, separating these structures from each other, and then cleaning the aedeagus of any residues and detaching the parameres. The dissected genitalic structures are then transferred to a new cavity slide containing glycerol for further study. After examination, the male genitalia are mounted on rectangular cards or triangular points, or are put into glycerol-filled microvials, and re-attached to original specimens for permanent storage.

Taxonomic review process

The main steps followed in the course of this study are listed here with the hope that this will help future students of Carabidae:

  1. Existing descriptions and keys to supraspecific taxa occurring in New Zealand were gathered from the world literature, e.g., Ball & Bousquet (2001) and Arndt et al. (2005) for subfamilies, Jeannel (1941–1942) and Lindroth (1961–1969) for tribes, and a wide range of publications for genera. 
  2. For each tribe, the external morphology of at least 10 specimens belonging to each species within every genus, was examined; character matrices (one per tribe) were built including as many generic characters as possible. This provided the base for generic descriptions and identification keys. 
  3. Tribal characters gathered from the world literature were assessed for all genera occurring in New Zealand, using the above-mentioned specimen samples. 
  4. Subfamilial characters were also assessed in the same way as for genera and tribes. 
  5. Character matrices built at each classificatory level (see 2, 3, 4) were used to draft descriptions for each subfamily, tribe, and genus. Writing the final descriptions also involved transferring selected characters from lower to higher ranking categories, when appropriate. 
  6. Identification keys were built in the same way as descriptions, with emphasis on the most diagnostic characters of the external morphology. 
  7. Only differential descriptions were prepared for subtribes and subgenera. No keys were prepared for these categories.
  8. Illustrative material accompanying descriptions and identification keys was prepared as a final step. 
Taxonomically relevant characters

The characters presented in the descriptions are subsets of the totality of adult characters (about 100) studied, and represent the most important differences between, or variation amongst, closely related taxa. Characters or states of characters not mentioned in the generic descriptions are as detailed in tribal descriptions; the same applies to tribes and subfamilies.

Body length was measured from apex of mandibles to apex of elytra (with the specimen in dorsal view), and is cited as a range.
Characters with the highest diagnostic value have been illustrated or photographed. Most illustrations provided in this work represent the most commonly encountered state of a character. The user must allow some degree of variation when working with individual specimens.
Characters selected for identification are those generally easily observed, which do not require genitalic dissection.

Illustrations and digital photographs

Illustrations (except habitus drawings and Fig. 118-119), including maps, were prepared and laid out using the software package CorelDRAW® graphics suite. Originals of habitus drawings and Fig. 118-119 were scanned, modified, and laid out using the same software. Photographs were captured through a Leica MZ-12.5 stereomicroscope, a LeicaDC500 digital camera, and the increased-depth-of-field computer system Auto-Montage (Synoptics U.K.). Further photo-processing was done with the software packages Adobe® Photoshop® and CorelDRAW® graphics suite.

Subfamilial and tribal concepts

Already existing world descriptions for subfamilies and tribes were adopted and adapted to the New Zealand situation (see section Taxonomic review process).

Generic concept

A genus should be a monophyletic group composed of one or more species separated from other genera by a decided gap. The phylogenetic framework to study Australasian Carabidae, however, is insufficiently elaborated to test this hypothesis for New Zealand genera. Consequently, existing generic concepts have in general been accepted. In addition, new genera are proposed for species not fitting the correlated character complex of species included in already described genera. Recognition of these generic taxa provides new hypotheses that will hopefully be tested by future students of the higher classification of Carabidae.

A cladistic analysis, preferably integrating morphological and genetic information, is needed to determine the phylogenetic position of New Zealand genera within the family Carabidae. Only then can an attempt be made to decipher the evolutionary history of the New Zealand taxa, e.g., to confirm or reject the hypothesis that certain genera are Gondwana relicts, to reconstruct the sequence of speciation and colonisation events, and to understand their evolution in general or that of their habitat relationships.

Taxonomic arrangement

In this synopsis subfamilies, tribes, and subtribes are arranged phylogenetically. The higher classification follows Arndt et al. (2005) for subfamilies, and Larochelle & Larivière (2001) for tribes and genera. The subtribal group-name Nothobroscina was created by Roig-Juñent (2000) for five New Zealand endemic broscine genera. The subtribal group-name Zolina was established by Roig-Juñent & Cicchino (2001) for two genera (one native, one endemic).

Further study of Australasian Carabidae is needed before phylogenetic relationships can be hypothesised for genera. Consequently, genera and subgenera are treated alphabetically within higher categories.

Genus-group names

Synonymies already provided by Larochelle & Larivière (2001) are not repeated here.

Biostatus

This is indicated for all genera (A=Adventive; E=Endemic; N=Native, not endemic), see Checklist of supraspecific taxa (p. 12). The biostatus categories are defined in the Glossary (Appendix A, p. 106). A combination of criteria was used to assess whether taxa were adventive including: recency of first New Zealand record in the literature and collections; fit of current geographical and ecological distribution with recognised natural patterns, or similarity of such distribution with that of other adventive arthropods; and dispersal ability, especially in relation to flightlessness and distance from the nearest overseas populations.

Geographic distribution and ecology

For New Zealand distribution records, the area codes of Crosby et al. (1976, 1998) are given in alphabetical order, for the North Island, South Island, Stewart Island, and the Offshore Islands, respectively.

Two-letter abbreviations for the area codes of Crosby et al. (1976, 1998) used in this publication are as follows (see Maps 1–3):

New Zealand. North Island: AK, Auckland; BP, Bay of Plenty; CL, Coromandel; GB, Gisborne; HB, Hawke’s Bay; ND, Northland; RI, Rangitikei; TK, Taranaki; TO, Taupo; WA, Wairarapa; WI, Wanganui; WN, Wellington; WO, Waikato. South Island: BR, Buller; CO, Central Otago; DN, Dunedin; FD, Fiordland; KA, Kaikoura; MC, Mid Canterbury; MK, Mackenzie; NC, North Canterbury; NN, Nelson; OL, Otago Lakes; SC, South Canterbury; SD, Marlborough Sounds; SL, Southland; WD, Westland. Stewart Island, SI. Offshore Islands: AN, Antipodes Islands; AU, Auckland Islands; BO, Bounty Islands; CA, Campbell Island; CH, Chatham Islands; KE, Kermadec Islands; SN, Snares Islands; TH, Three Kings Islands.

Maps summarising generic distributions are provided on pp. 166–175.

The ecological information provided is based on specimen label data, field and laboratory observations by the authors, and from the literature. In order to eliminate spurious records an effort was made to summarise available information by using the smallest common denominator amongst the greatest number of observations for each taxon. The terminology and style of presentation adopted here follow closely Larochelle & Larivière (2001). Many technical terms are also defined in the Glossary (Appendix A, p. 106).

References

Under References, only the most important taxonomic references are given for each taxon, with an indication of their contents between parentheses. Most references provided by Larochelle & Larivière (2001), dealing mainly with non-taxonomic aspects, are not repeated here.

Type data

Such information is listed for new species, in the following format: type status (holotype, lectotype, etc.) followed by sex, acronym of entomological collection or museum serving as repository, and original label data with a forward slash (/) indicating a different label. A forward slash already written on a label is indicated between quotation marks (“/”).

Material examined

For newly-described species, the number of specimens examined and the acronyms of their repositories are indicated.