Ectobius danekrae Anisyutkin et Perkovsky, 2024

Anisyutkin, Leonid N., Vasilenko, Dmitry V. & Perkovsky, Evgeny E., 2024, A new amber representative of the genus Ectobius Stephens, 1835 (Blattodea: Ectobiidae) from Storebaelt (Denmark), Zootaxa 5397 (3), pp. 342-350 : 343-346

Ectobius danekrae Anisyutkin et Perkovsky , sp. nov.

( Figs. 1A–E , 2A, B )

Etymology. Inspired by the Danish Statute, the term “danekrae ” was introduced in 1989 as a term for earth-found natural objects of unique natural historical value.

Material. Holotype, male, northwestern Zealand ( Denmark), Danish amber, late Eocene , with label “NHMD-624757 ex-DK 176 (1); ZMUC 902245 Musholm Bugt, Storebaelt Denmark, Region Sjaelland, Kalundborg Kommune. Leg. Jørgensen, Benny.

Det: Andersen, Nils, 07/06/1966 NATURAL HISTORY MUSEUM OF DENMARK ”

Description of inclusion ( Fig. 1A, B ). Cylindrical, very clear yellow amber piece, brought to light by sand pumping in Storebaelt (Bonde at al. 2008). The sample is oblong, 37 mm long. The amber contains an almost completely preserved adult male cockroach with mouthparts, wings, legs and genitalia.

Syninclusion: Hemiptera , Drepanosiphidae , Palaeophyllaphis longirostris Heie, 1967 ( Bonde et al. 2008).

Description. General color, as far as can be judged from the cockroach inclusion, light reddish (yellowish?) ( Figs. 1C–E ); facial part of head with two blackish spots: larger spot between eyes and smaller one between and below antennal sockets; antennae at least partly blackish; maxillary palps, especially apical segment, probably darker as compared with general color; disk of pronotum with large hexagon-like black spot; lateral parts of pronotum and costal field of tegmina lighter, yellowish; tegmina with darker space between veins; legs (with exception of blackish spots at distal ends of femora and proximal ends of tibiae), abdomen from below (with exception of slightly darkened median part) and cerci light reddish.

Dense pubescence visible on antennae, tarsi and cerci. Surfaces smooth, punctuation indistinct.

Head protruding weakly from under pronotum, subtriangular in shape ( Figs. 1C, D , 2A ); eyes large, interocular space wide; antennae long ( Figs. 1C, D , 2A ), with more than 40 antennomeres, about as long as or slightly shorter then body length; scapus largest and widest; pedicel short, conical in shape, thinner than scapus and wider than segments of flagellum; 1st flagellomere elongated, more than twice as long as wide, succeeding ~ 10 antennomeres short and transverse, subsequent segments gradually become longer, about twice as long as wide. Maxillary palps long, 3rd segment elongated, 4th elongated conical and 5th – subtriangular in shape; 3rd and 4th segments probably subequal in length, 5 – largest (unfortunately, it is impossible to accurately measure the size of maxillary palps segments on inclusion). Pronotum transverse ( Figs. 1C , 2A ), gradually widened caudally, anterior margin nearly straight, lateral – widely rounded, posterior – weakly protruded caudally. Scutellum distinct, in shape of isosceles triangle ( Figs. 1C , 2A ). Tegmina and wings fully developed ( Figs. 1C , 2A ), surpassed abdominal apex (forma macroptera sensu Anisyutkin 2022). Tegmina elongated, moderately coriaceous, with distinct venation. Sc about as half as tegmina length, forked apically. Costal field strongly elongated and narrow. R roundly curved, with more than 20 regularly arranged anterior rami. M indiscernible. CuA fused with R in proximal part, R+CuA with more than 17 simple and regularly arranged posterior rami. CuP widely curved, but sharply curved at the point of confluence with the posterior margin of tegmen. Anal veins 7–8, these veins partly subobsolete, elongated parallel to posterior margin of tegmen. Structure of wings indistinguishable, but anal field large. Legs with well developed armament ( Figs. 1D, E , 2B ). Anterior margin of fore femora armed probably according to type B (sensu Bey-Bienko 1950; Roth 2003), with at least one large apical spine ( Fig. 1D ). Fore tibia not thickened distally. Structure of hind tarsi ( Fig. 1D ): metatarsus slightly longer than other segments combined; 2nd and 5th segments elongated, subequal in length, 3rd segment slightly shorter than 2nd; 4th segment – very short; all segments with distinct apical pulvillae; metatarsus and probably second segment with two rows (rows poorly visible on inclusion) of spines along lower margin, other tarsal segments (as far as can be judged from the inclusion) without spines; claws weakly asymmetrical or symmetrical; arolium about half of claw length. Fore and mid tarsi similar to hind tarsi, but segments comparatively shorter. Abdominal sternites without visible specializations ( Figs. 1D , 2B ). Cercus long and flattened, about twice as long as hypandrium, with more than 7 distinct segments ( Figs. 1E , 2B ). Hypandrium elongated ( Figs. 1E , 2B ), subtriangular in shape, slightly asymmetrical, left caudolateral side seems to be more rounded than right one; left stylus large, evidently subcylindrical, outgrowth slightly narrowed towards the apex, with several chaetae or sensillae at apex; right stylus short, in shape of transverse asymmetrical outgrowth.

Measurements (mm). Total body length 16.1* (as preserved, from vertex to tegmen apex); head length 1.7*; head width 1.5*; pronotum length 1.5*; pronotum width 2.5*; tegmen length <5.5; tegmen width 2.2*; costal field length 3; anal field length 2.5; anal field width 1.2. Dimensions marked with * are approximate due to inclusion distortion and cockroach deformation.

Female unknown.

Comparison. The new species readily differs from the two known from Baltic amber species ( E. balticus and E. inclusus ) and extant species of the genus by presence of small right stylus. Additionally, E. danekrae sp. nov. differs from E. balticus in comparatively light colored abdomen (dark, nearly black in E. balticus – Germar and Berendt 1856 and data of authors) and from E. inclusus by comparatively short left stylus (left stylus strongly elongated in E. inclusus – Shelford 1910). Ectobius danekrae sp. nov. readily differs from described from Green River Formation E. kohlsi by uniformly coloured disc of pronotum and tegmina (pronotum and tegmina distinctly punctate in E. kohlsi – Vršanský et al. 2014). It is impossible to reliably distinguish the new species from all extant species (not all species of the genus have known males and the structure of styli), but those and E. danekrae sp. nov. are separated by more than 36 million years ( Iakovleva 2017; Iakovleva et al. 2021, 2022) and are too much to imply conspecificity.

The new species is somewhat similar to E. lapponicus in pattern of coloration. But the presence of such a unique character as the presence of a right stylus, only slightly asymmetrical tarsal claws and small arolia does not allow it to be attributed to any of the known species groups, including Ectobius lapponicus species group (see Vršanský et al. 2014).

Notes. A variation in the coloration of pronotum of E. balticus was mentioned by Shelford (1910). Single known specimen of E. danekrae sp. nov. is characterized by large dark spot on pronotum and comparatively light lower part of abdomen, as compared with fossil E. balticus and extant E. lapponicus Linnaeus, 1758 . The presence of a dark spot on pronotum and a light abdomen makes it unlikely that the specimen of E. danekrae sp. nov. is represented by a light form.

Additionally, species from the Baltic amber need revision, and it is highly probably that in Baltic amber more species are awaiting description.

All known to the authors representatives of the genus Ectobius have only one left stylus ( Bohn 1989). Bey-Bienko pointed out that “hypandrium with only one clear left stylus, right stylus absent or occasionally presented as an extremely small, poorly visible tubercle” ( Bey-Bienko 1950, p. 186). Unfortunately, Bey-Bienko not specified species with “extremely small, poorly visible” right stylus.

Figures

FIGURE 1. Ectobius danekrae Anisyutkin et Perkovsky, sp. nov., male holotype.A, B—general view of inclusion: from above (A) and below (B); C, D—general view from above (C) and below (D); E—abdominal apex from below.

FIGURE 2. Ectobius danekrae Anisyutkin et Perkovsky, sp. nov., male holotype. A—outlines of body from above; B— abdominal apex and part of leg from below.