Wednesday, August 16, 2017

[PaleoEntomology • 2017] Mesosticta davidattenboroughi • Mesostictinae subfam. nov., An Archaic Group of Platystictid Damselflies (Odonata: Zygoptera) from mid-Cretaceous Burmese Amber

Mesosticta davidattenboroughi
 Zheng, Wang, Nel, Jarzembowski, Zhang & Chang, 2017


Odonatans are quite rare in the fossil record compared with the other insects, especially in Cretaceous amber inclusions. The extant family Platystictidae is one of the most diverse Zygoptera, but short of fossil records. In this paper, a new species, Mesosticta davidattenboroughi sp. nov., is described from mid-Cretaceous Burmese amber, representing the third-known fossil species of Platystictidae. Mesosticta davidattenboroughi sp. nov. has a long IR1 beginning one cell distal of the base of RP2, confirming the previous attribution of Mesosticta Huang, Azar, Cai & Nel, 2015 to Platystictidae. It differs from other species of Mesosticta in having a long IR1 and a basally crossed subdiscoidal cell. The fossil genus Mesosticta shares the diagnostic characters of the modern platystictid genera, viz. a basally recessed ‘CuP’ (shared by all species), a very long IR1 (only in Mesosticta davidattenboroughi sp. nov.), and a specialized subdiscoidal area mostly rhomboidal in shape (only in Mesosticta electronica Zheng, Zhang, Chang & Wang, 2016). Based on the platystictid damselflies from Burmese amber, a new subfamily Mesostictinae subfam. nov. is established. Mesostictinae subfam. nov. represents the first fossil group of modern platystictid damselflies, documenting the appearance of Platystictidae as early as mid-Cretaceous. It differs from modern Platystictidae by the presence of fewer postnodal and postsubnodal crossveins, a short MP, the base of RP2 being nearer to the subnodus and the nodus lying more distally.

Keywords: Platystictidae, Zygoptera, Odonata, Cenomanian, Cretaceous, Burmese amber

Figure 1. Mesosticta davidattenboroughi sp. nov., holotype, NIGP164541, photograph of specimen. 

Order Odonata Fabricius, 1793
Suborder Zygoptera Selys-Longchamps, 1854
Superfamily Platystictoidea Kennedy, 1920
Family Platystictidae Kennedy, 1920
Subfamily Mesostictinae subfam. nov.
Type genus. Mesosticta Huang, Azar, Cai & Nel, 2015.

Mesosticta Huang, Azar, Cai & Nel, 2015 
Type species. Mesosticta burmatica Huang, Azar, Cai & Nel, 2015. 
Included species. Mesosticta electronica Zheng, Zhang, Chang & Wang, 2016; Mesosticta davidattenboroughi sp. nov. 

Mesosticta davidattenboroughi sp. nov. 

Type species. NIGP164541, two complete forewings attached to body.

 Diagnosis. Forewing characters: IR1 long, originating one cell distal of base of RP2, nearer to N than to Pt; Arc aligned with Ax2; subdiscoidal cell basally crossed by one vein. 

Etymology. In honour of Sir David Attenborough, on his 90th birthday, for his appreciation of dragonflies. 

Locality and horizon. Hukawng Valley, Kachin Province, Myanmar; lowermost Cenomanian, lowermost Upper Cretaceous.

Figure 7. Hypothetical position of Mesosticta davidattenboroughi sp. nov. in phylogenetic tree of Zygoptera. All line drawings are based on forewings (phylogeny based on Dijkstra et al. 2014; line drawing of Sinosticta ogatai Matsuki & Saito, 1996 after Wilson 1997; line drawing of Palaemnema picicaudata Kennedy, 1938 after Kennedy 1938; line drawings of Platysticta deccanensis Laidlaw, 1915 and Protosticta himalaiaca Laidlaw, 1917 after Fraser 1933).

Daran Zheng, Bo Wang, André Nel, Edmund A. Jarzembowski, Haichun Zhang & Su-Chin Chang. 2017. Mesostictinae subfam. nov., An Archaic Group of Platystictid Damselflies (Odonata: Zygoptera) from mid-Cretaceous Burmese Amber.  Journal of Systematic Palaeontology.   DOI: 10.1080/14772019.2017.1348395

David Attenborough gains new species namesake @physorg_com