A new genus of fungus weevils ( Coleoptera : Anthribidae ) in Rovno amber

New fungus weevils, Eduardoxenus unicus (ZooBank registration: urn:lsid:zoobank.org:act:5732 BC859148-4FE5-A4F6-46847BA0138D, urn:lsid:zoobank.org: act:4D3B3EA8-AE0E-4E6D-A770-B427AC19ED03) Legalov, Nazarenko et Perkovsky, gen. et sp. nov. (Coleoptera: Anthribidae), are described from late Eocene Rovno amber. The new genus is similar to the genus Cyptoxenus Valentine, 1982, but differs in coarsely faceted eyes, antennomere 2 shorter than antennomere 1 and an almost glabrous body. It differs from the genus Valenfriesia Alonso-Zarazaga et Lyal, 1999 in the coarsely faceted eyes, almost straight transversal carina on the pronotum and distinct elytral humeri, and it differs from the genus Neoxenus Valentine, 1999 in distinct lateral carina on the pronotum, coarsely faceted eyes and almost straight transversal pronotal carina. This fossil fungus weevil is the oldest finding of the tribe Valenfriesiini in fossil state and the first record of the Choraginae from the Eocene amber. The palaeogeographical and palaeoclimatological importance of finding Valenfriesiini in Rovno amber is discussed.


Introduction
Fungus weevils are a very diverse group of primitive weevils closely related to the family Nemonychidae and adapted to development in rotting wood or in seeds.More than 3800 species in more than 380 genera are known (Rheinheimer, 2004;Mermudes and Leschen, 2014).The oldest Anthribidae, the extinct Juranthribinae and Protoscelinae, date from the border of the Middle and Upper Jurassic (Legalov, 2011(Legalov, , 2013b)).Urodontinae is the isolated extant subfamily with a centre of diversity in South Africa but is also distributed in tropical Africa, North Africa and Eurasia (Louw, 1993).An un-described species of this subfamily is recorded from the Eocene Baltic amber (Hieke and Pietrzeniuk, 1984).Most species and supraspecific taxa of Anthribidae belong to the subfamily Anthribinae, which is recorded from the middle Cretaceous of the Russian Far East (Zherikhin, 1993;Legalov, 2013b;Nadein and Perkovsky, 2018).The Choraginae subfamily is widely distributed throughout the world but is much poorer in species.The earliest find of the Choraginae is known from the Early Cretaceous of Spain (Soriano et al., 2006).Several species of this subfamily were described from the Miocene Dominican amber (Poinar Jr. and Legalov, 2016).The Choraginae were not known earlier from the Eocene European amber (Legalov, 2015).In this paper, we describe a new genus with a new species belonging to the tribe Valenfriesiini.
Published by Copernicus Publications on behalf of the Museum für Naturkunde Berlin.The amber piece with inclusion is deposited in the Schmalhausen Institute of Zoology of the National Academy of Sciences of Ukraine, Kiev (SIZK), amber collection.
The morphological terminology used in this paper follows Lawrence et al. (2010).

Etymology:
The genus is named after the father of the last author.
Description: Size: length of body (without rostrum), 1.4 mm; length of rostrum, 0.2 mm.Body, black, covered with sparse short hairs, appears silvery shiny due to presence of cavities between specimen and internal surface of its impression.Head: about 1.8 times as long as rostrum; rostrum moderately short, about 0.6 times as long as it is wide at the apex and middle, about 0.5 times as long as it is wide at the base, about 0.3 times as long as the pronotum, straight, densely punctate, without dorsal median carina; labrum free, almost wide-rectangular; mandibles large; rostral pleurostomal sinus deep; forehead wide, about 1.1 times as wide as the rostrum base width; eyes large, convex, about 1.4 times as long as they are wide, with 9-10 rows of facets perpendicular to maximum length; vertex weakly flattened, finely punctate; temples moderately short; antennal scrobes foveiform; antennae inserted next to the lower portion of eyes dorsally, not geniculate, moderately long, reach elytral humeri; antennomeres 1-8 conical; antennomere 1 about 2.5 times as long as it is wide; antennomere 2 about 1.9 times as long as it is wide, 0.7 times as long as and 0.9 times as wide as antennomere 1; antennomere 3 about 3.3 times as long as it is wide, 0.8 times as long as and 0.4 times as wide as antennomere 2; antennomere 4 about 2.4 times as long as it is wide, 0.6 times as long as and 0.8 times as wide as antennomere 3; antennomeres 3 and 4 subequal in length; antennomere 5 about 3.0 times as long as it is wide, 0.8 times as wide as antennomere 4; antennomeres 5 and 6 subequal in width; antennomere 6 about 2.5 times as long as it is wide, 0.8 times as long as antennomere 5; antennomere 8 about 2.0 times as long as it is wide; club not compact; antennomere 9 conical, about 1.8 times as long as it is wide, 1.4 times as long as and 1.6 times as wide as antennomere 8; antennomere 10 about 1.8 times as long as it is wide, 1.3 times as long as and 1.3 times as wide as antennomere 9; antennomere 11 drop-shaped, subequal in length and wide to antennomere 10.Pronotum: bell-shaped; disk weakly flattened, densely and rugosely punctate; transverse dorsal pronotal carina antebasal, almost straight; distance between transverse carina and base of pronotum 0.3 times as long as the pronotum; lateral carina long, almost reaching apical margin of pronotum.Mesonotum: scutellum small, almost semicircular, lays in the pentagonal scutellar groove.Elytra: distinctly convex, about 2.5 times as long as the pronotum; greatest width in the middle, lacking scutellar striole; elytron without tubercles; humeri weakly convex; striae regular and distinct; strial punctures quite small, rounded, sparse; elytral intervals flattened, wide, about 1.5-2.0times as wide as the striae, sparsely and finely punctate; covered with sparse short thin sub-recumbent setae arranged in irregular rows on interstriae, slightly shorter and thinner setae on the borders of strial punctures; epipleuron distinct.Thorax: coarsely punctate; pre-and postcoxal portions of prosternum short; procoxal cavities narrowly separated; mesocoxal cavities rounded, narrowly separated; metanepisternum narrow, 9.8 times as long as it is wide in the middle.Metaventrite about 3.1 times as long as the metacoxal cavity length.Abdomen: convex, weakly flattened in middle; ventrite 1 about 1.6 times as long as the length of metacoxal cavities; ventrite 2 about 0.9 times as long as the length of ventrite 1; ventrite 3 about 0.9 times as long as the length of ventrite 2; ventrite 4 about 0.7 times as long as the length of ventrite 3; ventrite 5 about 1.8 times as long as the length of ventrite 4; pygidium concealed by elytra.Legs: long; pro-and mesocoxae round; metacoxae transverse; femora weakly clavate, without teeth; profemora about 2.2 times as long as they are wide; metafemora about 2.6 times as long as they are wide; tibiae almost straight, without apical spurs; protibiae about 6.9 times as long as they are wide in the middle; mesotibiae about 8.7 times as long as they are wide at the middle; metatibiae about 11.5 times as long as they are wide at the middle; tarsi long; tarsomeres 1-3 with pulvilli on the underside; tarsomeres 1-3 conical; tarsomere 2 embracing tarsomere 3 laterally; tarsomere 3 bilobed; tarsomere 4 short; tarsomere 5 elongate; tarsal claws divergent, with large teeth at base; protarsi: tarsomere 1 about 1.7 times as long as it is wide; tarsomere 2 about 1.4 times as long as it is wide, 1.1 times as long as and 1.3 times as wide as tarsomere 1; tarsomere 3 about 1.3 times as long as it is wide, 0.6 times as long as and 0.7 times as wide as tarsomere 2; tarsomere 5 about 7.0 times as long as it is wide, 2.6 times as long as and 0.5 times as wide as tarsomere 3; mesotarsi: tarsomere 1 about 2.2 times as long as it is wide; tarsomere 2 about 1.6 times as long as it is wide, 1.1 times as long as and 1.5 times as wide as tarsomere 1; tarsomere 3 about 1.1 times as long as it is wide, 0.6 times as long as and 0.9 times as wide as tarsomere 2; tarsomere 5 about 4.8 times as long as it is wide, 2.1 times as long as and 0.5 times as wide as tarsomere 3.

Discussion
The family Anthribidae is not known from Palaeocene deposits but is well represented in the Eocene faunas.The American Eocene faunas of the Green River (early-mid-Eocene) and Florissant (terminal Eocene) are largely similar and contain the tribes Cratoparini, Tropiderini, Anthribini, Discotenini, Ecelonerini and Zygaenodini (Legalov, 2015(Legalov, , 2018;;Kirejtshuk et al., 2018).The tribes Allandrini and Zygaenodini with predominance of the genus Glaesotropis Gratshev et Zherikhin, 1995 (Zygaenodini) are presented in the Baltic and Rovno ambers (Gratshev and Zherikhin, 1995;Gratshev and Perkovsky, 2008;Legalov, 2012Legalov, , 2013aLegalov, , 2015;;Kirejtshuk et al., 2018).A total of 18 species from the eight genera of the tribes Cratoparini, Platystomini, Eugonini, Piesocorynini, Choragini and Valenfriesiini were described from Miocene Dominican and Mexican ambers (Poinar Jr. and Legalov, 2016).The Paleogene representatives of the subfamily Choraginae were known from the Eocene of the USA (Green River: Scudder, 1890) and the Oligocene of Germany (Rott: Heyden and Heyden, 1866).The species from tribes Choragini and Valenfriesiini were found in the Dominican amber.The new genus is the oldest finding of the tribe Valenfriesiini in fossil state and the first record of the Choraginae from Eocene ambers.
Valenfriesiini are distributed almost exclusively in the tropics, more abundant on Saint Helena and the Antilles, and known in Holarctic region only from Japan, Kuril Islands, central Taiwan and Texas.Most of the records of Valenfriesiini are associated with non-Holarctic vegetation.The tropical elements in the late Eocene floras of Volyn' Elevation (of the same age as the Rovno amber forest) are distinctly poorer than we previously supposed (Perkovsky et al., 2010), although they are more abundant than in the Baltic amber forest (Sokoloff et al., 2018).In the Rovno amber fauna Valenfriesiini represents the fourth taxon of a suprageneric rank, which is also unknown from the Baltic amber fauna (the rest are the extinct crabronid tribe Protomicroidini, figitid subfamily Eucoilinae Thomson, 1862 and Capniidae stoneflies; Perkovsky et al., 2010;Buffington et al., 2014).At the same time, the taxa of the generic rank unknown from the Baltic amber are quite abundant: only Hymenoptera is represented by 19 genera (Perkovsky, 2018), and this number will increase along with investigation of the Rovno fauna.We can assume that Valenfriesiini belong to the group of taxa for which the southern coast of Subparathetys (Jałoszyński and Perkovsky, 2016) was the northernmost boundary of their geographic range, e.g. the ant genus Fallomyrma Dlussky et Radchenko, 2006, known from the Rovno (type species and three other species), Bitterfeld and Scandinavian ambers (type species) (Perkovsky, 2011;Radchenko and Dlussky, 2018).The climate of the southern coast of Subparathetys was much warmer than that of the Baltic amber forest (Wolfe et al., 2016;Mänd et al., 2018), which determined a much higher share of the tropical elements in the fauna (Perkovsky, 2013(Perkovsky, , 2016(Perkovsky, , 2017)).Some tropical elements from Bitterfeld and Rovno amber, e.g.Thallisellini (Erotylidae: Languriinae), the Litochropus genus group (Phalacridae) (Lyubarsky andPerkovsky, 2016, 2017) and the extremely thermophilic (Vladimir Ivanov, personal communication, 2013) trichopteran genus Leptocerus Leach, 1815 (Ivanov et al., 2016) are unknown from Baltic amber.