Ephistemus crassipes Lyubarsky et Perkovsky, 2019

User, GBIF. Org, 2019, Occurrence Download, Russian Entomological Journal 28 (1), pp. 54-57 : 56-57

Ephistemus crassipes Lyubarsky et Perkovsky , sp.n.

Figs 1–3 .

MATERIAL. Holotype: 1223-2, in collection of Christel and Hans Werner Hoffeins (Hamburg), Yantarnyi , Baltic amber, Late Eocene. The type will be deposited at the amber collection of Senckenberg Deutsches Entomologisches Institut Müncheberg ( SDEI), Germany. Collection code: CCHH.

DESCRIPTION. Length of body 1.2 mm, body round, convex ( Fig.1 ), covered with very minute sparse punctures and bearing small and very fine decumbent hair. Body, legs and antennae entirely dark brown.

Head transverse, finely punctured, distance between punctures more than diameter of puncture; with hemispherical facetted eyes; length of eye 4 times less than width of head. Eye prominent, normally developed, one eye smaller than the distance between the eyes. Head not constricted behind eye. Antennae slender, with club reaching beyond base of pronotum, joints of flagellum elongate, about 1.5 times as long as broad, antennomere 1 elongated, slightly curved, a little longer than 2 nd, antennomere 3 up to over 2.5 times the length of 4. Antennomeres 4–8 th short, 1.5 times as long as broad, 9 th slightly transverse, narrower than 10 th, 10 th transverse, 11 th obliquely oval, joints 9–11 asymmetrical, equal in width, antennomere 11 th longer than 10 th, slightly compressed. Antennal insertions widely separated basally. Antennal grooves on head and prosternum present. Frontoclypeal suture present.

Pronotum strongly transverse, 4 times as broad as long, weakly and finely punctured, distance between punctures equal to 4 their diameters. Anterior edge not sinuate, anterior angles without thickening or callosity. Pronotal sides converging anteriorly, greatest width at base. Base of the pronotum without depression in the middle; basal pits absent, hind angles rectangular; pronotal disk convex.Basal margin slightly lobed. Prosternum without punctation. Prosternal process with parallel lines. Width of mesosternal process greater than mesocoxa. Metasternum rarely punctured. On all the legs, the femur and tibia are approximately equal in length to each other. The foretarsus approximately half the length of the foretibia ( Fig. 2 ), the metatarsus approximately two-thirds the length of the metatibia. The anterior femora thickened, approximately equal to the width of the epimeron at the base, the foretibia thickened, only slightly narrower than the femur. The tibia at the apex about twice as thick as the base. The tarsi wide, their width about half the maximal width of the tibia. Tarsomeres with fairly large lobes. Tarsal formula 5-5-5. Tibia without spurs. Longitudinal metasternal line absent. Meta-intercoxal process wider than long. Femoral line absent. Ventrite 5 evenly arcuate; ventrite 5 without crenulations, surface unmodified.

Scutellum small, pentagonal, transverse. Elytra shortoval, moderately convex, humeral corners rounded, weakly curved at sides, maximum breadth of elytra in first third of their length, 3 times as long as pronotum, 1.4 times as long as broad. Surface shining, densely punctured, punctures in basal part slightly stronger than on pronotal disk, and approximately 4 diameters apart their lateral neighbors on an average. Elytral impression absent. Epipleuron present to level of posterior margin of metasternum. Wings fully developed.

ETYMOLOGY. The species is named crassipes , because in contrast to other members of the genus, it has thick femora and tibia.

REMARKS. This species differs from other members of the genus Ephistemus by thickened femur and tibia.

The genus is known from Holarctic, Oriental region and Central America, circumtropical. Ephistemus apicalis LeConte, 1863 distributed in USA; E. distans Sharp, 1900 , in Guatemala; E. globulus (Paykull, 1798) , in Algeria, Italy, Germany, Norway, Russia, Georgia, Iran, China, USA, New Zealand; E. perminutus Casey, 1924 , in USA; E. reitteri Casey, 1900 , in United Kingdom, France, Spain, Portugal, Italy, Greece, Germany, Switzerland, Austria, Czechia, Hungary, Poland, Bulgaria, Russia, Azerbaijan, Iran, Turkey, Israel; E. splendens Johnson, 1971 , in Pakistan, India, Nepal, China.

Other species of the genus are usually distinguished by the elytral punctation and the size of the body, color and shagreening of elytra, the relative width of the segments of antennal club. For example, E. splendens differs by very large and sparse punctation of pronotum and elytra. E. exiguus differs from the new species by a much more transverse antennal club. The new species differs primarily in the structure of the legs. It has wider femur and tibia than other species of the genus. The tarsi are somewhat longer and thicker than those of recent species. The new species does not differ in the punctation of elytra. For example, itdoes not differ from E. globulus , punctured rarely and weakly, much weaker than E. splendens . In E.globulus , the hind tarsi are slightly thickened, with small pubescent lobes. Unlike E. reitteri , the new species does not have shagreened elytra (and has thicker legs).

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; Sokoloff et al., 2018; Perkovsky, Olmi, 2018; Perkovsky, 2018], which determined a much higher share of the tropical elements in the fauna [ Perkovsky, 2013, 2016, 2017]. Some tropical elements from Bitterfeld and Rovno amber, e.g. Thallisellini ( Erotylidae : Languriinae), the Litochropus genus group ( Phalacridae ) [ Lyubarsky, Perkovsky, 2016, 2017a], Valenfriesiini ( Anthribidae ) [ Legalov et al., 2018] are unknown from Baltic amber, others are represented by single specimen, e.g. Corethrellidae [ Baranov et al., 2016]. In the same time Holarctic and cosmopolitan taxa strongly prevail in Baltic amber [ Perkovsky, 2016, 2017]; interesting, that all Late Cretaceous atomariines are known from colder Baeomorpha realm [Lyubarsky, Perkovsky, 2014, 2015, 2017b; Gumovsky et al., 2018]. It will be important to study the connections between these and Late Eocene European atomariines.

Acknowledgements. We are grateful to Christel and Hans Werner Hoffeins (Hamburg, Germany) for providing the material, to Vitaly Yu. Nazarenko (Schmalhausen Institute of Zoology, Kiev, Ukraine) for kindly taking photographs of the specimen, Alexandr P. Rasnitsyn ( Borissiak Paleontological Institute , Moscow, Russia) for discussion. The work of the first author has been supported by the grant AAAA-A16-116021660077 - 3 .

Figures

Figs 1–2. Ephistemus crassipes sp.n.: 1 — lateral view; 2 — structure of tarsi. Рис. 1–2. Ephistemus crassipes sp.n.: 1 — сбоку; 2 — строение лапок.

Fig. 3. Drawing of ventral view of E. crassipes sp.n. Рис. 3. Вид сниЗу E. crassipes sp.n. (рисунок).