Hiatomegops, 2022

Guo, Xiangbo, Selden, Paul A. & Ren, Dong, 2022, New specimens from Mid-Cretaceous Myanmar amber illuminate the phylogenetic placement of Lagonomegopidae (Arachnida: Araneae), Zoological Journal of the Linnean Society 195, pp. 399-416 : 404-406

GENUS HIATOMEGOPS GUO ET AL. gen. nov.

Zoobank registration: u r n: l s i d: z o o b a n k. org:act: F0561F03-E69D-45E6-A7FB-4A4D3BFEC6EE

Etymology: The genus name is the combination of hiatus, opening in Latin, after the broad tracheal spiracle behind the epigastric furrow, and Lagonomegops , type genus of the family, from Greek -μεγόψ, magnification. The name is masculine.

Type species: Hiatomegops spinalis sp. nov.

Diagnosis: Palpal tibia and tarsus with several dorsal trichobothria; leg metatarsus slightly longer than tarsus; broad tracheal spiracle situated on postgastric area behind epigastric furrow.

Remarks: Finding a fossil spider species in which both males and females have been described is rare. Among 19 reported genera in Lagonomegopidae , only Archaelagonops Wunderlich, 2012 is known from both male and female specimens. The two female specimens, which were subsequently included in Archaelagonops (erected on a male specimen originally), lack sufficient evidence to belong in that genus ( Wunderlich, 2012, 2015). In general, female spiders are a larger size than conspecific males. Four lagonomegopid species, Lineaburmops beigeli , Lineaburmops maculatus Wunderlich, 2015 , Parviburmops brevipalpus Wunderlich, 2015 and Planimegops parvus Wunderlich, 2017 , comprised only of male specimens, were described as having a similar or smaller size with CNU-ARA-MA2020002, an adult female. CNU-ARA-MA2020002 can be distinguished from them by: carapace without white patch (carapace with distinct white patches in Lineaburmops beigeli and Lineaburmops maculatus ); carapace much longer than wide (carapace length equal with width in Parviburmops brevipalpus ); cephalic region of carapace with a pair of anterolateral protrusions next to the inner side of PME (protrusions absent in Planimegops parvus ). We erected a new genus Hiatomegops based on CNU-ARA-MA2020002. Hiatomegops can be distinguished from the other two lagonomegopid genera ( Lagonoburmops and Picturmegops ) comprised only of female specimens by: body length 2.89 (body length about 8.00 in Lagonoburmops ); carapace piriform in outline, much longer than wide (carapace distinctly narrowed posteriorly, slightly wider than long in Picturmegops ); carapace without a stripe (carapace with distinct stripes in Picturmegops ); metatarsus of leg I slightly longer than tarsus (metatarsus of leg I about two times longer than tarsus in Lagonoburmops ).

In addition, the holotypes of Grandoculus chemahawinensis Penney, 2004 ,? Lagonomegops cor Pérez-de la Fuente et al., 2013, Soplaogonomegops unzuei Pérez-de la Fuente et al., 2013, Spinomegops aragonensis Pérez-de la Fuente et al., 2013 and Spinomegops arcanus Pérez-de la Fuente et al., 2013 were identified as ‘juvenile or adult female’ ( Penney, 2004; Pérez-de la Fuente et al., 2013). Hiatomegops can be easily separated from these by: carapace piriform in outline, without neck (carapace heart-shaped when viewed from above in? Lagonomegops cor ; cephalic region constricted in a neck, with narrowest point medially in Soplaogonomegops unzuei ), fovea small oval, deeply depressed (fovea absent in Spinomegops aragonensis and Spinomegops arcanus ), leg I not enlarged, metatarsus and tarsus without scopulae (leg I distinctly longer and more robust than the others, metatarsus and tarsus with scopulae hairs in Grandoculus chemahawinensis ).