Mecodema antarcticum

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Mecodema antarcticum
Specimen from Castlecliff Beach, Whanganui, New Zealand
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Carabidae
Genus: Mecodema
Species:
M. antarcticum
Binomial name
Mecodema antarcticum
(Laporte, 1867)
Synonyms[1]
  • Brullea antarctica Laporte, 1867

Mecodema antarcticum is a carnivorous carabid beetle that burrows in sand above the high tide mark on New Zealand sandy beaches. First described by Francis de Laporte de Castelnau in 1867 as Brullea antarctica, it has since been reassigned to Mecodema.[2]

Description[edit]

Mecodema antarcticum is large (up to 25 mm), glabrous reddish brown to black with a distinct "waist" or narrowing between thorax and abdomen (peduncle), like all Mecodema.[3] Indeed, recent DNA analysis places it within that genus, a sister group to Mecodema curvidens; its distinctive differences in body shape may be adaptations to burrowing in sand.[4]

This species legs are well-adapted for digging in sand with greatly expanded coxa, femur and tibia: all tibia are greatly expanded at their distal ends, and the middle and hind pairs are also strongly curved.[5] Other features consistent with dwelling in and on sand are the short antennae, large curved mandibles, and a rather boxy shape in contrast to the longer and more elegant forest Mecodema species. The abdomen of M. antarcticum is covered in long setae to further protect it from abrasion. Its larval form was unknown for some time, and was first described in 1978.[6][7]

Description[edit]

Mecodema antarcticum is found in the supralittoral or splash zone of sandy beaches around the New Zealand coast, underneath logs or stones, hiding in the sand during the day and emerging at night to feed.[8][9] It was described by George Hudson as "usually rare",[8] but is a secretive burrowing beetle, and occasionally is discovered in reasonable numbers.[10] It was rediscovered by schoolchildren on the Whanganui coast in 2006 after not being recorded for many years.[11]

Mecodema antarcticum has been recorded being heavily preyed on by katipō spiders,[10] and it may be threatened by the introduced South African spider Steatoda capensis, either as a predator or competitor.[12]

References[edit]

  1. ^ "Mecodema antarcticum". Global Biodiversity Information Facility. Retrieved 1 August 2022.
  2. ^ "Mecodema antarcticum (Laporte, 1867)". Catalogue of Life. Retrieved 2023-03-11.
  3. ^ Britton, Everard B. (1949). "The Carabidae (Coleoptera) of New Zealand: Part III—A Revision of the Tribe Broscini". Transactions of the Royal Society of New Zealand. 77 (4): 533–581. Retrieved 14 October 2016.
  4. ^ Goldberg, Julia; Knapp, Michael; Emberson, Rowan M.; Townsend, J. Ian; Trewick, Steven A. (2014). "Species Radiation of Carabid Beetles (Broscini: Mecodema) in New Zealand". PLOS ONE. 9 (1): e86185. Bibcode:2014PLoSO...986185G. doi:10.1371/journal.pone.0086185. ISSN 1932-6203. PMC 3900486. PMID 24465949.
  5. ^ Roig-Juñent, Sergio (2000). "The subtribes and genera of the tribe Broscini (Coleoptera: Carabidae): cladistic analysis, taxonomic treatment, and biogeographical considerations". Bulletin of the American Museum of Natural History. 255: 1. doi:10.1206/0003-0090(2000)255<0001:tsagot>2.0.co;2. S2CID 85796620.
  6. ^ Harris, A. C. (1978). "The larva of Brullea antarctica (Coleoptera: Carabidae: Broscinae)". New Zealand Entomologist. 6 (4): 401–405. doi:10.1080/00779962.1978.9722304.
  7. ^ Harris, A. C. (1980). "The larva of Brullea antarctica (Coleoptera: Carabidae: Broscinae): note". New Zealand Entomologist. 7 (2): 174–175. doi:10.1080/00779962.1980.9722369.
  8. ^ a b Hudson, George Vernon (1934). New Zealand Beetles and Their Larvae. Wellington: Ferguson and Osborn. pp. 33–34.[permanent dead link]
  9. ^ Brooks, Paul (27 April 2016). "Collect beetles for museum study". Wanganui Midweek. Retrieved 2 May 2016.
  10. ^ a b Bull, R. M. (1959). "A note on the occurrence of Brullea antarctica Castelnau (Coleoptera: Carabidae) at Otaki Beach". New Zealand Entomologist. 2 (4): 9. doi:10.1080/00779962.1959.9722773.
  11. ^ Beautrais, Margie (13 February 2012). "Conservation: Seaweek tribute to national treasure". Wanganui Chronicle. Retrieved 7 March 2016.
  12. ^ Gardner-Gee, Robin; Graham, Sharen; Griffiths, Richard; Habgood, Melinda; Heiss Dunlop, Shelley; Lindsay, Helen (2007). Motuora Native Species Restoration Plan (PDF). Auckland: Department of Conservation & Motuora Restoration Society. p. 89.