Platystigma pronoti (Atlantic Helicopter)

[sebbe67]

Mecistogaster pronoti is known only from the type locality. The species was never collected again after its original description in 1918. Habitat is threatened by deforestation.


Espirito Santo state in Brazil.

[Bowhead Whale]

What are "Mecistogaster", exactly?

[Melanie]

a dragonfly which had lived in the rainforest.

[Bowhead Whale]

And what was the description made of it, in 1918?

[Melanie]

Sorry, but this description cannot be find in the web. It is published in an old publication by Y. Sjöstedt in 1918 and perhaps in some books about Brazilian dragonflies which i am not aware of.

[Bowhead Whale]

Oh...

[Melanie]

Scientific Name: Mecistogaster pronoti
Species Authority: Sjöstedt, 1918
Common Name/s:
English – Atlantic Helicopter
Assessment Information [top]
Red List Category & Criteria: Critically Endangered B1ab(iii) ver 3.1
Year Assessed: 2006
Assessor/s von Ellenrieder, N. & Paulson, D.
Evaluator/s: Clausnitzer, V. & Suhling, F. (Odonata Red List Authority)
Justification:
Mecistogaster pronoti is known only from the type locality. The species was never collected again after its original description. Habitat is threatened by deforestation. There is an urgent need to survey forests in vicinity of type locality.
Geographic Range [top]
Range Description: Espirito Santo state in Brazil.
Countries:
Native:
Brazil
Population [top]
Population: Current population size is unknown.
Population Trend: Unknown
Habitat and Ecology [top]
Habitat and Ecology: Atlantic rain forest.
Systems: Terrestrial; Freshwater
List of Habitats:
1 Forest
1.6 Forest - Subtropical/Tropical Moist Lowland
Threats [top]
Major Threat(s): Deforestation.
List of Threats:
5 Biological resource use
5.3 Logging & wood harvesting
5.3.5 Motivation Unknown/Unrecorded
Conservation Actions [top]
Conservation Actions: There is an urgent need to survey forests in the vicinity of the type locality. Then studies are needed to establish the species' range of distribution, biology, population trends and to evaluate threats.
Bibliography [top]
Citations:

Baillie, J. and Groombridge, B. (compilers and editors) 1996. 1996 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland.

Groombridge, B. (ed.) 1994. 1994 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland.

IUCN. 1990. 1990 IUCN Red List of Threatened Animals. IUCN, Gland, Switzerland and Cambridge, UK.

IUCN. 2006. 2006 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 04 May 2006.

Sjöstedt, Y. 1918. Wissenschaftliche Ergebnisse der Swedischen Entomologischen Reise des Herrn Dr. A. Roman in Amazonas 1914-1915. 1, Odonata. Arkiv vor Zoologi (Ark. Zool.) 11(15): 1–54.

www.iucnredlist.org/details/12921/0

[Melanie]

Sjostedts scientific description (in German) is available here: www.archive.org/details/arkivfrzoologi11kung Unfortunately with no illustration. BTW: the common name Atlantic Helicopter sounds nice.

[Sebbe]

Redescription of the holotype of Mecistogaster pronoti Sjöstedt, 1918 (Zygoptera: Pseudostigmatidae)

Mecistogaster pronoti Sjöstedt, 1918 was described based on a female holotype deposited in the Naturhistoriska Riksmuseet, Stockholm, collected in the state of Espírito Santo, Brazil. The original description has no illustrations, which makes its identification very difficult. Herewith we redescribe and illustrate this holotype. The species is red listed and considerations regarding its conservation are made.

www.researchgate.net/publication/303780124_Redescription_of_the_holotype_of_Mecistogaster_pronoti_Sjostedt_1918_Zygoptera_Pseudostigmatidae?_sg=Bg0D5khWY1tQrUz360i7HvklCrZS0Ey7tbSUzftDHRHsz4lqIVnyCrUC6nF3V90hZDhcmEKL3jgthWci1OCUZQ

[Sebbe]

Revalidation of Platystigma Kennedy, 1920, with a synopsis of the quadratum species group and the description of three new species (Odonata: Pseudostigmatidae).

Platystigma pronoti (Sj ӧstedt, 1918) n. comb.

Figures 12 , 18 , 33–36

Sj ӧstedt (1918: 31); Davies & Tobin (1984: 57); Garrison & Ellenrieder (2016: 20); Machado (1992: 19); Bridges (1994: 39); Tsuda (2000: 58); Machado, Drummond & Martins (2005: 96); Heckman (2008: 205); Garrison, Ellenrieder & Louton (2010: 391); Schorr & Paulson (2016); Machado & Lacerda (2016: 63).

Material examined. Holotype ♀: Brazil, Espírito Santo (no further information available) . Holotype deposited in the NHMS.

Diagnosis. Head with dorsum black and orange-white spots anteriorly and another medially to antennae base. Pronotum dark brown with pair of pale yellow stripes anteriorly and laterally to middle lobe. Border of medial and apex of lateral portions of posterior prothorax lobe pale yellow. Median portion straight, separated from lateral portions by deep incision at each side ( Fig. 12 ); lateral portions with apex rounded ( Fig. 12 ). Mesepisternum ( Fig. 18 ) black with antehumeral grayish-yellow stripe occupying whole extension of sclerite. Mesepimeron dark brown with grayish-yellow stripe not reaching lower part of sclerite. Metapleuron ( Fig. 18 ) whitish yellow with black stripe adjacent to metapleural suture occupying dorsal ¾ of sclerite. Venter of pterothorax whitish yellow, with narrow middle dark stripe occupying its anterior ½. It is impossible to know whether this stripe reaches the posterior part of the venter, because it is damaged. Supplementary tooth of tarsal claws absent. Wings dominantly hyaline with apical area milky-white reaching a row of cells posterior to RP1. Pseudostigma in both wings weakly indicate pale yellow color ( Figs. 33, 35 ). At high saturation, the color of apical area changes; the white color becomes pale blue and the pseudostigma appears very evident, yellow, with six cells in Fw and eight in Hw ( Figs. 34, 36 ). Costal vein becomes orange and RA to RP1 yellow ( Figs. 34, 36 ). Abdomen dominantly brown. Cercus dark, with apex rounded. Ovipositor (stylus lacking) reaching posteriorly about level of hind border of S10.

Measurements (mm): Hw 40. Abdomen 54.

Male: unknown.

Remarks. Mecistogaster pronoti is transferred here to Platystigma based on its small size, absence of supplementary tooth of tarsal claw and presence of pale apical areas on the wings. The species was described by Sj ӧstedt (1918) based on a single female specimen from the state of Espírito Santo, Brazil, and has never been found again. According to Heckman (2008), “ M. pronoti is a rare or unrecognized species.” The holotype of P. pronoti has been recently redescribed and illustrated by Machado & Lacerda (2016), thus allowing its easy identification. The main character separating P. pronoti from the other Platystigma species is the peculiar form of the hind prothoracic lobe, whose median portion is clearly separated from the lateral ones. P. pronoti has been listed as Critically Endangered in Brazil’s, Portarias MMA n o 444/445 (2014) and IUCN (2006) red list, and a strategy for its conservation has been proposed by Machado & Lacerda (2016).

www.mapress.com/zt/article/view/zootaxa.4242.3.4

[Sebbe]

Livro Vermelho da Fauna Brasileira Ameaçada de Extinção volume vii – invertebrados 2018.

Mecistogaster pronoti is endemic to Brazil and is known only from the female type specimen from Espírito Santo. In the Atlantic Forest, the larvae of Mecistogaster species are frequently found in tree hollows. Females of this genus have been observed ovipositing in these environments. These are forest species and, considering the intensity of habitat loss with conversion to agriculture and urbanization within the range of occurrence, it can be concluded that their population is severely fragmented with continued decline of vegetation and loss of habitat quality. Furthermore, there have been no records of this species for at least 96 years, despite the fact that it has been sought by experts for several years in Espírito Santo, southern Bahia and Rio de Janeiro. For these reasons, Mecistogaster pronoti has been categorized as Critically Endangered, Possibly Extinct (CR-PEX), by criterion B1ab(iii,iv).

www.gov.br/icmbio/pt-br/centrais-de-conteudo/publicacoes/publicacoes-diversas/livro_vermelho_2018_vol7.pdf

[Sebbe]

It was assessed as Critically Endangered/Possibly Extinct in the 2022 edition of the Brazilian Red List.