Thursday, February 23, 2023

[PaleoEntomology • 2022] Alienopterix santonicus • A Metallic Cockroach from the Late Cretaceous Ajkaite Amber (Bakony Mts, western Hungary) documents Alienopteridae within the Mesozoic Laurasia


Alienopterix santonicus  
Szabó, Szabó, Kóbor & Ősi, 2022. 

 artwork by Márton Zsoldos  facebook.com: Zsoldos Paleo Art

Abstract
Cockroaches (Blattaria s. str.) were documented from numerous amber localities around the world, representing both extinct and extant families. Alienopteridae is an extinct cockroach family known only from the Cretaceous of Gondwana (Brazil, Botswana, Myanmar amber) and the Cenozoic of North America. Alienopterix santonicus sp. n. from the Late Cretaceous amber of the Ajka Coal Formation (Bakony Mts, western Hungary) extends the rich geographical distribution of the family into Laurasia during the Mesozoic. As a member of the presumably pollinator cohort Alienopteridae, this species could have played an important role in the Ajka Coal ecosystem during the Santonian. The microrectangular structures of the forewing suggest that the new species likely possessed a metallic colouration already known from the group. Combined with the disruptive body pattern this could have served as an advanced camouflage. The microrectangular structures of the forewing were compared to integument microstructures of extant insects with metallic colouration. Various arthropod taxa are already known from ajkaite, and the new discovery further emphasizes the importance of this amber.

Keywords: Fossil insect, Santonian, Blattaria, Umenocoleoidea


Order Blattaria, Latreille 1810 
= Blattodea Brunner von Wattenwyl, 1882 
(cockroaches without termites, mantodeans and chresmodids)

Superfamily Umenocoleoidea Chen et Tian, 1973
Family Alienopteridae Bai et al., 2016
 = Aethiocarenidae Poinar et Brown, 2017

Type genus: Alienopterus Bai, Beutel, Klass, Wipfler et Zhang in Bai et al. (2016). 
Stratigraphic range: Barremian—Eocene
Geographic range: Gondwana and Laurasia (by the present study)


Subfamily Alienopterixinae Vršanský in Vršanský et al. (2021b)

Genus Alienopterix Mlynský, Vršanský et Wang, in Vršanský et al. (2018)

Type species: Alienopterix ocularis Mlynský, Vršanský et Wang, 2018

Stratigraphic range: Cenomanian—Santonian
Geographic range: North Myanmar amber and Hungarian ajkaite amber (present study)

Alienopterix santonicus sp. n. (SARA AT.10.24.1), holotype.
a Habitus in dorsal view. b Habitus in ventral view. c Head in dorsal view. d Details of antennules.
Scale bars: 0.5 mm (a, b), 0.2 mm (c), 0.1 mm (d)

Alienopterix santonicus sp. n.

Type material. SARA AT.10.24.1. (holotype, ?male).

Type locality. Ajka-Csingervölgy, appr. 1 km SE of the city Ajka (Bakony Mts, Hungary).

Horizon and age. Ajka Coal Formation, unknown shaft of the Ajka-Csingervölgy coal minery; Upper Cretaceous, Santonian (86.3–83.6 Ma).

Etymology. The name santonicus is derived from the Santonian age of the Ajka Coal Formation where the specimen originates from.

Differential diagnosis. Genus Alienopterix currently includes three valid species: A. mlynskyi, A. ocularis and A. smidovae. Alienopterix santonicus sp. n. clearly differs from all known species of the genus based on the combination of the following characters. Unlike in A. santonicus sp. n., epicranial sutures are visible in A. mlynskyi. Antennomeres of A. mlynskyi are less than two times as long as wide, while those of A. santonicus sp. n. are more than two times as long as wide. The species A. ocularis lacks the characteristic secondary structure of the forewing, while forewings of A. santonicus sp. n. are covered with microrectangular structures. Unlike A. santonicus sp. n., A. ocularis has a distinct, campaniform pronotum. Also, antennal segments of A. ocularis are subequal, while those of A. santonicus sp. n. are more than two times as long as wide. Antennal segments of A. smidovae are subequal and rich in short and dense sensillae, while those of A. santonicus sp. n. are more longer than wide and comparatively sparse in sensillae.
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Artistic reconstruction of Alienopterix santonicus sp. n., with hypothetical greenish-reddish colouration
(artwork by Márton Zsoldos)


  Márton Szabó, Péter Szabó, Péter Kóbor and Attila Ősi. 2022. Alienopterix santonicus sp. n., A Metallic Cockroach from the Late Cretaceous Ajkaite Amber (Bakony Mts, western Hungary) documents Alienopteridae within the Mesozoic Laurasia. Biologia. DOI: 10.1007/s11756-022-01265-7