''Mecodema antarcticum'' is a carnivorous

carabid Ground beetles are a large, cosmopolitan family of beetles, the Carabidae, with more than 40,000 species worldwide, around 2,000 of which are found in North America and 2,700 in Europe. As of 2015, it is one of the 10 most species-rich animal fam ...

beetle that burrows in sand above the high tide mark on New Zealand sandy beaches. First described by

Francis de Laporte de Castelnau Francis may refer to: People *Pope Francis, the head of the Catholic Church and sovereign of the Vatican City State and Bishop of Rome *Francis (given name), including a list of people and fictional characters *Francis (surname) Places * Rural M ...

in 1867 as ''Brullea antarctica'', it has since been reassigned to ''

Mecodema ''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 Noth ...

.''

Description

''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 ''

''. Indeed, recent DNA analysis places it within that genus, a sister group to ''

Mecodema curvidens ''Mecodema curvidens'' Broun is a medium-bodied ground beetle that is geographically widespread throughout the central areas of the North Island The North Island, also officially named Te Ika-a-Māui, is one of the two main islands of New ...

''; its distinctive differences in body shape may be adaptations to burrowing in sand. 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 Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

ends, and the middle and hind pairs are also strongly curved. 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.

Description

''Mecodema antarcticum'' is found in the

supralittoral The supralittoral zone, also known as the splash zone, spray zone or the supratidal zone, sometimes also referred to as the white zone, is the area above the spring high tide line, on coastlines and estuaries, that is regularly splashed, but not su ...

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. It was described by George Hudson as "usually rare", but is a secretive burrowing beetle, and occasionally is discovered in reasonable numbers. It was rediscovered by schoolchildren on the Whanganui coast in 2006 after not being recorded for many years. ''Mecodema antarcticum'' has been recorded being heavily preyed on by katipō spiders, and it may be threatened by the introduced South African spider ''

Steatoda capensis Steatoda capensis is a spider originating from South Africa. Its common names include the ''black cobweb spider'', ''brown house spider'', ''cupboard spider'' and due to its similarities to the katipō spider it is commonly known as the ''fal ...

,'' either as a predator or competitor.

References

{{Taxonbar, from=Q113377988 Broscinae Taxa named by François-Louis Laporte, comte de Castelnau Beetles of New Zealand Endemic fauna of New Zealand Beetles described in 1867 Endemic insects of New Zealand