Mecodema is a genus of large flightless ground beetle (Carabidae) endemic to New Zealand. The genus is very diverse in comparison to the other three New Zealand genera (Diglymma, Oregus, Orthoglymma) within the subtribe Nothobroscina (tribe Broscini). Mecodema is geographically widespread across both the North and South Islands, as well as numerous offshore islands, including the Three Kings Is., Poor Knights Is., Aotea (Great Barrier Is.) and Hauturu (Little Barrier Is.), Kapiti Is., Stephens Is., Stewart Is., Chatham Is., Snares Is.
Genus description Head, frons and vertex often rugose and / or punctate, microsculpture or macrosculpture absent in some species groups (e.g., curvidens species); eyes prominent, almost hemispherical; a single supraorbital puncture on each side, bearing more than one setae; setose punctures of vertex absent; mandibles large, uniformly narrow to the pointed apex, sharply curved in the apical third, mandibles with a number of dorsal grooves and without a seta in the scrobe; mentum with median process, which is notched to strongly indentate (bifid); usually with 2 setiferous punctures (may be absent) below the process and generally with 4–8 setose (setiferous) punctures along the submentum sclerite; labial palpi with setae on the penultimate segment; terminal segments of all palpi slightly compressed, sub-cylindrical, truncate; ligula chitinous with a median carina, 2 apical setae present; the membranous paraglossae extended well beyond the apex of the ligula; stipes with 2–3 basal setae; antennomeres I–II glabrous, III–V with apical ring, VI–XI setose throughout; antennomeres I–III subcylindrical, IV–VII subglobose and slightly compressed. Prothoracic carina (pronotal lateral margin) distinct with an asymmetrical number of setae along each side, the last never at the posterior lateral sinuation (posterior angle); midline (median groove) and pronotal foveae (laterobasal depressions) always present; pronotal disc often with shallow depressions on each side of apical half. Elytra always striate; fused together along the suture; hind wings absent; a row of setose punctures on the 7th stria and another row (umbilical series) near the lateral carina (elytral margin). Legs slender, the protibia with a pointed apical prolongation on the outer side, greatly distally expanded to distally expanded and shovel-like; male and female tarsi identical, the basal 4 segments of the anterior tarsi are as broad as they are long, usually slightly asymmetrical.
Type species: Mecodema sculpturatum Blanchard 1853.
Species and subspecies (106)
Mecodema aberrans (Putzeys, 1868) Mecodema allani Fairburn, 1945 Mecodema altum Fong & Seldon, 2026 Mecodema alternans Laporte de Castelnau, 1867 Mecodema alternans hudsoni Broun, 1909 Mecodema angustulum Broun, 1914 Mecodema antarcticum (Laporte de Castelnau, 1867) Mecodema aoteanoho Seldon & Leschen, 2011 Mecodema argentum Seldon & Buckley, 2019 Mecodema atrox Britton, 1949 Mecodema atuanui Seldon & Buckley, 2019 Mecodema brittoni Townsend, 1965 Mecodema bullatum Lewis, 1902 Mecodema chaiup Seldon, 2015 Mecodema chiltoni Broun, 1917 Mecodema constrictum Broun, 1881 Mecodema costellum Broun, 1903 Mecodema costellum gordonense Broun, 1917 Mecodema costellum lewisi Broun, 1908 Mecodema costellum obesum Townsend, 1965 Mecodema costipenne Broun, 1914 Mecodema crenicolle Castelnau, 1867 Mecodema curvidens (Broun, 1915) Mecodema ducale Sharp, 1886 Mecodema dunense Townsend, 1965 Mecodema dunnorum Seldon & Buckley, 2019 Mecodema dux Britton, 1949 Mecodema elongatum Castelnau, 1867 Mecodema femorale Broun, 1921 Mecodema florae Britton, 1949 Mecodema fulgidum Broun, 1881 Mecodema genesispotini Seldon & Buckley, 2019 Mecodema godzilla Seldon & Buckley, 2019 Mecodema gourlayi Britton, 1949 Mecodema haakuturi Seldon & Pou, 2024 Mecodema haunoho Seldon & Leschen, 2011 Mecodema hector Britton, 1949 Mecodema howitti Castelnau, 1867 Mecodema huttense Broun, 1915 Mecodema impressum Castelnau, 1867 Mecodema infimate Lewis, 1902 Mecodema integratum Townsend, 1965 Mecodema jacinda Seldon & Buckley, 2019 Mecodema kahurangi Fong & Seldon, 2026 Mecodema kipjac Seldon & Buckley, 2019 Mecodema kokoroiho Seldon & Buckley, 2019 Mecodema kokoromatua Seldon, Leschen & Liebherr, 2012 Mecodema laeviceps Broun, 1904 Mecodema laterale Broun, 1917 Mecodema litoreum Broun, 1886 Mecodema longicolle Broun, 1923 Mecodema lucidum Castelnau, 1867 Mecodema manaia Seldon & Leschen, 2011 Mecodema metallicum Sharp, 1886 Mecodema minax Britton, 1949 Mecodema mohi Seldon & Buckley, 2019 Mecodema moniliferum (Bates, 1867) Mecodema morio (Castelnau, 1867) Mecodema ngaiatonga Seldon & Buckley, 2019 Mecodema ngaitahuhu Seldon & Buckley, 2019 Mecodema nitidum Broun, 1903 Mecodema oblongum (Broun, 1882) Mecodema oconnori Broun, 1912 Mecodema oregoides (Broun, 1894) Mecodema papake Seldon & Buckley, 2019 Mecodema parataiko Seldon & Leschen, 2011 Mecodema pavidum Townsend, 1965 Mecodema perexiguum Seldon & Buckley, 2019 Mecodema persculptum Broun, 1915 Mecodema pluto Britton, 1949 Mecodema politanum Broun, 1917 Mecodema ponaiti Seldon & Leschen, 2011 Mecodema proximum Britton, 1949 Mecodema puiakium Johns & Ewers in Johns, 2007 Mecodema pulchellum Townsend, 1965 Mecodema punctatum (Laporte de Castelnau, 1867) Mecodema punctellum Broun, 1921 Mecodema puncticolle Broun, 1915 [?=Mecodema sculpturatum Blanchard, 1843] Mecodema quoinense Broun, 1912 Mecodema rectolineatum Laporte de Castelnau, 1867 Mecodema regulus Britton, 1964 Mecodema rex Britton, 1949 Mecodema rugiceps Sharp, 1886 Mecodema rugiceps anomalum Townsend, 1965 Mecodema rusticulus Seldon & Buckley, 2019 Mecodema scitulum Broun, 1894 Mecodema sculpturatum Blanchard, 1843 Mecodema simplex Castelnau, 1867 Mecodema spiniferum Broun, 1880 Mecodema striatum Broun, 1904 Mecodema strictum Britton, 1949 Mecodema temata Seldon & Buckley, 2019 Mecodema tenaki Seldon & Leschen, 2011 Mecodema teparawhau Seldon & Buckley, 2019 Mecodema teroroa Seldon & Buckley, 2019 Mecodema tewhara Seldon & Buckley, 2019 Mecodema tibiale (Laporte de Castelnau, 1867) Mecodema tititea Fong & Seldon, 2026 Mecodema tuhoe Seldon & Buckley, 2019 Mecodema undecimus Seldon & Buckley, 2019 Mecodema validum Broun, 1923 Mecodema venator Broun, 1883 Mecodema wharekahika Seldon & Buckley, 2019 Mecodema xylanthrax Seldon & Buckley, 2019 Mecodema yconomus Seldon & Buckley, 2019 Mecodema zonula Seldon & Buckley, 2019
References
Further reading Seldon, D. S. (2015). A unique species of Mecodema (Carabidae: Broscini) from the Hawke's Bay region, New Zealand, with implications for North–South Island zoogeography. New Zealand Entomologist, 38(1), 28–35. Seldon, D. S., & Leschen, R. A. (2011). Revision of the Mecodema curvidens species group (Coleoptera: Carabidae: Broscini). Zootaxa, 2829(1), 1-45. Seldon, D. S., Leschen, R. A. B., & Liebherr, J. K. (2012). A new species of Mecodema (Carabidae: Broscini) from Northland, New Zealand, with notes on a newly observed structure within the female genitalia. New Zealand Entomologist, 35(1), 39–50. Townsend, J. I. (1965). Notes on the genus Mecodema (Coleoptera: Carabidae) with descriptions of new species from the South Island of New Zealand. New Zealand Journal of Science, 8(3), 301–318. Townsend, J. I. (1971). Entomology of the Aucklands and other islands south of New Zealand: Coleoptera: Carabidae: Broscini. Pacific Insects Monograph, 27, 173–184. NZ Entomologist Royal Society of New Zealand Landcare Research