Phloiotrya inmarinata, Alekseev & Bukejs, 2021

Alekseev, Vitalii Igorevich & Bukejs, Andris, 2021, Fossil Melandryidae (Coleoptera: Tenebrionoidea) from Eocene Baltic amber of the Sambian peninsula: new genus, six new species, new records and key to described taxa, Zootaxa 4965 (1), pp. 142-166 : 146-149

Phloiotrya inmarinata sp. nov.

( Figs. 2–3 , 8B , 9B )

Type material. Holotype: No MMO 1 7657/945 [ MWO], “* Holotype / Phloiotrya / inmarinata sp. nov. / Alekseev et Bukejs des. 2021” [red handwritten label]; adult, male. A complete beetle with partially exposed apical portion of aedeagus included in a transparent, yellow-orange amber piece with approximate dimensions of 19 mm × 12 mm and a maximum thickness of 8 mm; preserved without supplementary fixation. Syninclusions are represented by one Pselaphinae specimen ( Coleoptera : Staphylinidae ), one Psychodidae specimen ( Diptera : Nematocera) and a few stellate fagacean trichomes. The amber piece with inclusion may have been thermally processed in an autoclave, that is supposed because visible shrinking of body parts and black discoloration of syninclusions ( Hoffeins 2012).

Type stratum. Baltic amber from Eocene amber-bearing blue Earth layers, mostly Bartonian age is interpreted for the extinct central European resin-producing forests ( Bukejs et al. 2019).

Type locality. Yantarny settlement (formerly Palmnicken), Sambian (Samland) Peninsula, Kaliningrad Region, Russia .

Description. Measurements: body length about 6.7 mm, body maximum width 2.25 mm; pronotum length 1.5 mm, pronotum maximum width 2.1 mm; elytra length 5.2 mm, elytra maximum width 2.25 mm.

Body elongated, slightly convex dorsally; dark, unicolorous. Dorsal surface evenly punctured and covered with fine, decumbent pubescence.

Head inflexed downwards, invisible in dorsal view; frons and vertex slightly convex. Fronto-clypeal suture very fine. Labrum transverse, apically emarginate. Compound eyes large, entire, slightly prominent, oval, vertical; facets fine, without intrafacetal setae; interocular distance at upper margin of eyes approximately equal to vertical diameter of one eye. Maxillary palpi about 0.4× as long as antenna; 4-segmented: palpomere 1 cylindrical, 2× longer than wide; palpomere 2 and 3 equal in length, in form of right-angled triangle; palpomere 4 large, about 3× longer than wide, cultriform, not wider than palpomeres 2 or 3. Ratio of relative lengths of maxillary palpomeres 1–4 = 4:5:5:14. Antennae 11-segmented, filiform, inserted between and close to anterior inner margin of eyes, reaching posteriorly to elytral one-fourth; antennomeres 3–10 equal in size, cylindrical, elongate, about 3× longer than wide; antennomere 11 narrowly ovoid with pointed apex. Ratio of relative lengths of antennomeres 1–11 = 8:6:6:6:6:6:6:6:6:6:10.

Pronotum transverse, 1.4× wider than long, widest in posterior one-third; densely and finely punctured, distance between punctures equal to 0.2–1.0× diameter of one puncture (punctuation denser posteriorly and laterally). Pronotal base closely associated with elytral base, disc without distinct basal impressions. Anterior pronotal margin arcuate. Posterior margin weakly bisinuated, finely but distinctly margined. Lateral sides rounded, converging anteriad and weakly narrowed posteriad. Lateral pronotal carina present, anteriorly incomplete, indistinct near anterior angles (about one-eighth of the length). Anterior pronotal angles rounded, posterior angles obtuse. Notosternal suture distinct, carinate. Procoxal cavities without fissure (trochantin not visible), laterally closed. Prosternal process acute, triangular, reaching one-third of procoxal length. Scutellar shield transverse, oval, about 1.5× wider than long, punctate.

Elytra elongate, about 2.3× longer than wide, widest in anterior one-third, subparallel-sided in anterior twothird, gradually narrowed in posterior one-third; elytral apices rounded separately; elytral punctuation irregular, small and dense, similar to pronotal punctuation. Elytral striae or longitudinal costae absent. Metathoracic wings not visible. Epipleura narrow, widest basally and gradually narrowed posteriad, reaching abdominal ventrite 1.

Legs slender, long. Procoxae contiguous basally, egg-shaped, projecting below prosternum; mesocoxae rounded, narrowly separated; metacoxae elongate oval, transverse, narrowly separated. Femora and tibiae flattened, finely punctate. Tibiae almost straight, slightly dilated apically, subequal in length to femora, with two short spurs of equal length and fringe of short bristles apically; metatibial spurs as long as metatibial width at apex. Apices of meso- and metatibiae concave. Tarsi long, metatarsus nearly as long as metatibia; tarsal formula 5-5-4; penultimate tarsomere of all legs bilobed. Protarsomeres 1–4 widened (sexually dimorphic character showing that specimen is male). Metatarsomere 1 long, slightly longer than one half of metatibia. Ratio of relative lengths of metatarsomeres 1–4 = 4:1.5:0.5:0.7. Pretarsal claws simple, falcate, symmetrical.

Abdomen with five visible ventrites; ventrite 5 with deeply emarginate apical margin making the following sternites visible. Ratio of relative lengths of ventrites 1–5 = 2.5:2.5:2:2:1.5 (laterally).

Apical portion of aedeagus as in Fig. 8B .

Etymology. The specific epithet is derived from “ in mari natus ” (feminine: in mari nata), a Latin phrase meaning “born from/in sea”. The name is used as compound adjective and refers to: (1) the place of the holotype deposition, i.e. the Museum of the World Ocean in Kaliningrad, (2) the near-coastal region of the amber origin, (3) the place of last stage of the amber formation in glauconitic marine sediments.

Differential diagnosis. Phloiotrya inmarinata sp. nov. differs from extant species of the genus in the following combination of characters: (1) pronotum and elytra finely and densely punctate, without granulation or rugosity; (2) elytra uniformly weakly convex, without longitudinal costae; (3) apical maxillary palpomere long, about 3× longer than wide; (4) acute triangular prosternal process reaching one-third of procoxal length; (5) lateral pronotal carina distinct in basal seven-eighth of the length; (6) pronotum weakly transverse; (7) abdominal ventrite 5 (in male) with deeply emarginate apical margin; and (8) body dark, unicolorous.

Figures

FIGURE 2. Phloiotrya inmarinata sp. nov., holotype, No MMO 1 7657/945 [MWO]:A—habitus, dorsal view; B—habitus, left lateral view. Scale bars represent 1.0 mm.

FIGURE 3. Phloiotrya inmarinata sp. nov., holotype, No MMO 1 7657/945 [MWO]: A—details of forebody, ventro-lateral view; B—abdomen, ventro-lateral view. Not reproduced to the same scale.

FIGURE 8. Apical portion of aedeagus in ventral view: A—Electroxylita chronographica gen. et sp. nov.; B—Phloiotrya inmarinata sp. nov.; C—Madelinia capillata sp. nov.; D—Symphora pollocki sp. nov. Not reproduced to the same scale.

FIGURE 9. Reconstructions of new fossil Melandryidae from Baltic amber:A—Electroxylita chronographica gen. et sp. nov.; B—Phloiotrya inmarinata sp. nov.; C—Microscapha kugelanni sp. nov.; D—Madelinia capillata sp. nov.; E—Symphora glaesonauta sp. nov. Not reproduced to the same scale, punctuation and setation are omitted.