Biology:Megadromus speciosus
| Megadromus speciosus | |
|---|---|
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| Megadromus speciosus found in Marlborough, New Zealand | |
Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Coleoptera |
| Family: | Carabidae |
| Genus: | Megadromus |
| Species: | M. speciosus
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| Binomial name | |
| Megadromus speciosus Johns, 2007
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| Observations of Megadromus speciosus from iNaturalist (as of August, 2024). | |
Megadromus speciosus is a species of ground beetle (family Carabidae), endemic to New Zealand and of high conservation interest.[1]
Distribution and habitat
Megadromus speciosus (Picton ground beetle) is found in just a few forest remnants, in northern South Island New Zealand.[1][2] The species is typically found under stones and logs, and in areas with deep leaf litter.[2] The habitat is heavily influenced by the presence of wild pigs, which have caused extensive damage to the soil surface and understorey vegetation, particularly at Port Underwood.[2] The species also shows a preference for undisturbed native vegetation.[2]
The species is confined to isolated populations in the Marlborough Sounds, northern South Island, New Zealand.[2] Specifically, it is found at Port Underwood Saddle and Arapawa Island.[2] The Arapawa Island population appears to be more secure, while the Port Underwood population is under threat from habitat degradation.[2] A historical report suggested the presence of the species on Blumine Island, but this was not confirmed in recent surveys.[2] Niche modelling used to study the distribution of this genus found that 50% of the predicted range of Megadromus speciosus is within the New Zealand protected areas network.[3]
Morphology
Megadromus speciosus is described as a large, stout-bodied beetle with a length of 23-26 mm.[2] The dorsal surface of the head and pronotum is greenish, while the elytra have a coppery-purple sheen.[2] Male genitalia are distinct, with an enlarged mesotibia and a forked left paramere.[2] The morphological conservatism within the genus makes species identification challenging without examining genitalia.[2]
Taxonomy
Megadromus speciosus was described in 2007 by Peter Johns from specimens collected from Nothofagus forest near Picton (Port Underwood).[1] The genus Megadromus is part of the Carabidae family, which comprises large, flightless beetles.[2]
Genetic analysis of mitochondrial DNA sequences (COI and ND1 genes), show that M. speciosus is distinct from other related species, with significant sequence divergence.[2]
Conservation status
Under the New Zealand Threat Classification System, this species is listed as "Relict" with the qualifiers of "Range Restricted" and "Biologically Sparse".[4][1] The species is formally protected under the Wildlife Amendment Act (1980) and has been included in various conservation ranking systems due to its vulnerability to habitat modification and introduced predators.[2]
The primary threat to Megadromus speciosus is habitat degradation caused by wild pigs, especially at Port Underwood Saddle.[2] The pigs have extensively damaged the soil surface and understorey vegetation, which are critical for the species' survival.[2]
References
- ↑ 1.0 1.1 1.2 1.3 Johns, Peter Malcolm (2007). "New Genera and Species of Rare New Zealand Endemic Carabids. (Coleoptera: Carabidae)". Privately Published. https://www.researchgate.net/publication/242535691.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 Pawson, Stephen M.; Armstrong, Karen F. (February 2007). "A morphological and molecular comparison of island and mainland populations of Megadromus speciosus (Coleoptera: Carabidae) from the Marlborough Sounds, New Zealand" (in en). New Zealand Entomologist 30 (1): 13–23. doi:10.1080/00779962.2007.9722147. ISSN 0077-9962. Bibcode: 2007NZEnt..30...13P. http://www.tandfonline.com/doi/abs/10.1080/00779962.2007.9722147.
- ↑ Fuller, Lauren; Johns, Peter M.; Ewers, Robert M. (2013). "Assessment of protected area coverage of threatened ground beetles (Coleoptera: Carabidae): a new analysis for New Zealand". New Zealand Journal of Ecology 37 (2): 184–192. ISSN 0110-6465. https://www.jstor.org/stable/24060780.
- ↑ Leschen, R. A.B.; Marris, J. W.M.; Emberson, R. M.; Nunn, J.; Hitchmough, R. A.; Stringer, I. A.N. (2012-07-01). "The conservation status of New Zealand Coleoptera". New Zealand Entomologist 35 (2): 91–98. doi:10.1080/00779962.2012.686311. ISSN 0077-9962. https://doi.org/10.1080/00779962.2012.686311.
Wikidata ☰ Q21323658 entry
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