Megadytes ducalis

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Megadytes ducalis
Megadytes ducalis Sharp, 1882 (Dytiscidae) Holotype Brazil (42556946761).jpg
Holotype of Megadytes ducalis, housed in the Natural History Museum, London
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Dytiscidae
Genus: Megadytes
Species:
†M. ducalis
Binomial name
†Megadytes ducalis
Sharp, 1882

Megadytes ducalis is a species of water beetle in the family Dytiscidae. It is the largest species in the family. [2] Until recently, the species was only known from a single specimen that was collected in the 19th century from Brazil, [3] but more specimens, also collected in the 19th century from Brazil, were discovered in 2019. [4] Although listed as extinct by the IUCN, the limited studies conducted on water beetles in Brazil means that it might still survive. [3]

Contents

History

The first specimen of M. ducalis was collected in the 19th century from an unknown locality in Brazil and is kept at the Natural History Museum, London. [3] Rumors indicated it was found in the bottom of a canoe in the Amazon. [2]

In 2019, a study reported 10 additional specimens (including the first female of the species), all collected in the late 19th century, discovered incidentally in the National Museum of Natural History of France. While the original holotype lacked any exact location data, the new specimens all indicate that they were collected in Santo Antonio da Barra (now known as Condeuba) in the southern part of Bahia, Brazil. Villagers in the region were involved in insect trade, capturing the much sought after specimens of Hypocephalus armatus found around the region. [4]

As a consequence of the lack of recent records, the IUCN lists it as extinct. [1] Considering the absence of information about the species and the limited studies conducted on water beetles in Brazil, it might still survive. [3]

Morphology

Megadytes ducalis is a large and robust beetle with total length ranging from 42.9 to 47.4 mm (1.69–1.87 in). It is distinctly larger than congeners such as M. lherminieri and M. magnus , and not as broadly oval in shape as them. The two sexes of M. ducalis are externally similar, except for females being shiny without any signs of striae on the dorsal surface, and lacking protarsal disks and yellow setae on ventral surface of mesotarsomere I. [4]

Distribution

This species appears to have a restricted distribution in the cerrado, with the only known specimens being from Condeuba in Bahia, eastern Brazil. [4] If it still survives, it is likely to be seriously threatened from habitat loss. [4]

Related Research Articles

<span class="mw-page-title-main">Dytiscidae</span> Family of beetles

The Dytiscidae – based on the Greek dytikos (δυτικός), "able to dive" – are the predaceous diving beetles, a family of water beetles. They occur in virtually any freshwater habitat around the world, but a few species live among leaf litter. The adults of most are between 1 and 2.5 cm (0.4–1.0 in) long, though much variation is seen between species. The European Dytiscus latissimus and Brazilian Megadytes ducalis are the largest, reaching up to 4.5 cm (1.8 in) and 4.75 cm (1.9 in) respectively. In contrast, the smallest is likely the Australian Limbodessus atypicali of subterranean waters, which only is about 0.9 mm (0.035 in) long. Most are dark brown, blackish, or dark olive in color with golden highlights in some subfamilies. The larvae are commonly known as water tigers due to their voracious appetite. They have short, but sharp mandibles and immediately upon biting, they deliver digestive enzymes into prey to suck their liquefied remains. The family includes more than 4,000 described species in numerous genera.

<i>Dytiscus latissimus</i> Species of beetle

Dytiscus latissimus is a large species of aquatic beetle in family Dytiscidae. It is native to Europe and considered threatened.

<i>Megadytes</i> Genus of beetles

Megadytes is a genus of diving beetles in the family Dytiscidae. They are found in slow-moving or static freshwater habitats throughout most of the Neotropics, ranging from Florida and Mexico, through the West Indies and Central America, to South America as far south as central Argentina. The adult beetles measure about 1.65–4.75 cm (0.6–1.9 in) long depending on the exact species and the largest is also the largest in the family.

Meridiorhantus orbignyi is an extinct species of predaceous diving beetle in the family Dytiscidae. This species was formerly a member of the genus Rhantus.

<i>Coptotomus</i> Genus of beetles

Coptotomus is a genus of predaceous diving beetles in the family Dytiscidae, the only genus of the subfamily Coptotominae. There are about six described species in Coptotomus, found in North America and the Neotropics.

Hydroporus subpubescens is a species in the family Dytiscidae, in the order Coleoptera ("beetles"). It is found in North America.

Agabetes acuductus is a species of predaceous diving beetle found in the United States and Canada. Its habitat includes wooded wetlands, in the leaf litter of shaded pools, and cattail ponds.

Celina slossoni is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.

Agabus obliteratus is a species in the family Dytiscidae, in the order Coleoptera ("beetles"). It is found in North America.

Ilybius fraterculus is a species of predaceous diving beetles in the family Dytiscidae. It is found in North America.

Sanfilippodytes compertus is a species of predaceous diving beetles in the family Dytiscidae. It is found in North America.

Agabus ancillus is a species of predaceous diving beetles in the family Dytiscidae. It is found in North America.

<i>Bidessonotus inconspicuus</i> Species of beetle

Bidessonotus inconspicuus is a species of predaceous diving beetles in the family Dytiscidae. It is found in North America.

Oreodytes scitulus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.

<i>Graphoderus liberus</i> Species of beetle

Graphoderus liberus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America.

Megadytes fraternus is a species of predaceous diving beetle in the family Dytiscidae. It is found in North America and the Neotropics.

<span class="mw-page-title-main">Cybistrini</span> Tribe of beetles

Cybistrini is a tribe of predaceous diving beetles in the family Dytiscidae. There are 7 genera and 128 described extant species in Cybistrini. The same set is also called Cybistrinae by authors viewing is as a subfamily of Dytiscidae.

Liadroporus is an extinct genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Liadroporus, L. elegans.

Mesoderus is an extinct genus of predaceous diving beetles in the family Dytiscidae. There are at least four described species in Mesoderus.

Mesodytes is an extinct genus of predaceous diving beetles in the family Dytiscidae. There is one described species in Mesodytes, M. rhantoides.

References

  1. 1 2 World Conservation Monitoring Centre (1996). "Megadytes ducalis". IUCN Red List of Threatened Species . 1996: e.T12944A3400572. doi: 10.2305/IUCN.UK.1996.RLTS.T12944A3400572.en . Retrieved 16 November 2021.
  2. 1 2 G.N. Foster; D.T. Bilton (2014). "The Conservation of Predaceous Diving Beetles: Knowns, Unknowns and Anecdotes". In D.A. Yee (ed.). Ecology, Systematics, and the Natural History of Predaceous Diving Beetles (Coleoptera: Dytiscidae). pp. 437–462. ISBN   978-94-017-9109-0.
  3. 1 2 3 4 Adriano Pereira Paglia (2007). Espécies ameaçadas da fauna brasileira: análise dos padrões e dos fatores de ameaça (PDF). Instituto de Ciências Biológicas - Universidade Federal de Minas Gerais.
  4. 1 2 3 4 5 Hendrich, Lars; Manuel, Michael; Balke, Michael (2019-04-18). "The return of the Duke—locality data for Megadytes ducalis Sharp, 1882, the world's largest diving beetle, with notes on related species (Coleoptera: Dytiscidae)". Zootaxa. 4586 (3): 517–535. doi: 10.11646/zootaxa.4586.3.8 . ISSN   1175-5334. PMID   31716121.


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