Archaeonebria inexspectata Schmidt & Kavanaugh, 2019

Schmidt, Joachim, Scholz, Stefan & Kavanaugh, David H., 2019, Unexpected findings in the Eocene Baltic amber forests: Ground beetle fossils of the tribe Nebriini (Coleoptera: Carabidae), Zootaxa 4701 (4), pp. 350-370 : 353-365

publication ID

https://doi.org/ 10.11646/zootaxa.4701.4.2

publication LSID

lsid:zoobank.org:pub:6417DB61-737F-443E-B91B-CF1723A891E8

DOI

https://doi.org/10.5281/zenodo.5617574

persistent identifier

https://treatment.plazi.org/id/E86787E1-FFC0-FFFD-FF39-D3E1FCFBFBBA

treatment provided by

Plazi

scientific name

Archaeonebria inexspectata Schmidt & Kavanaugh
status

sp. nov.

Archaeonebria inexspectata Schmidt & Kavanaugh View in CoL , sp. n.

Type material. Holotype: Male in Baltic amber; Coll. Carsten Gröhn in the collection of the Geological-Palaeontological Institute of the University of Hamburg ( GPIH), now in the Centrum of Natural History , Hamburg (CeNak), with collection number „ GPIH no. 4980, coll. Gröhn no. 7919”. For better investigation of the fossil, the stone was cut in two pieces, with one piece bearing the Nebriini fossil, and has a size of approx. 24 x 6 x 7 mm (irregularly cut) (= „ GPIH no. 4980, coll. Gröhn no. 7919a”, Fig. 1 View FIGURES 1–3 ); the remaining piece has a size of approx. 35 x 20 x 16 mm (irregularly cut) (= „ GPIH no. 4980, coll. Gröhn no. 7919b”).

Preservation status: The amber is clear but pervaded by several flowlines and partly covered by very fine surface cracks; the embedded Nebriini fossil is extensively covered by flowlines and bubbles adjoining the beetle body ( Figs 2–3 View FIGURES 1–3 ) and thus, hardly visible using light microscope. The exoskeleton of the specimen and its negative imprint on the inclusion wall is well preserved and could therefore be imaged in detail using micro-CT ( Figs. 4–6 View FIGURES 4–6 , 31, 32, 34 View FIGURES 31–36 ), as well as the aedeagal median lobe, except for the weekly sclerotized structures ( Figs 42-49 View FIGURES 42–53 ).

Syninclusions: One Nematocera fly and a dirt particle in the „ GPIH no. 4980, coll. Gröhn no. 7919a” piece, an additional Nematocera fly in the „ GPIH no. 4980, coll. Gröhn no. 7919b” piece.

Paratype #1: Female in Baltic amber; deposited in the University of California, Museum of Palaeontology , Berkeley , CA, with specimen number UCMP 403984.01 View Materials , and locality number IP 15208 ( Fig. 9 View FIGURES 7–10 ). Size of the piece approx. 31 x 20 x 8 mm .

Preservation status: The amber is clear, pervaded by very few flowlines, partly covered by very fine surface cracks; the embedded Nebriini fossil is partly covered by milky coating and a small bubble adjoining the dorsal surface of the beetle body ( Fig. 7 View FIGURES 7–10 ). Parts of the metatarsi are cut and thus lost. The exoskeleton of the Nebriini fossil and its negative imprint on the inclusion wall are moderately well preserved and could therefore be imaged in most details using micro-CT ( Figs. 11–13 View FIGURES 11–13 ). Traces of the fossilized gonocoxites could also be imaged.

Syninclusions: One Trichoptera, three Nematocera flies (two of which are preserved in mating position), one Coleoptera : Scirtidae , stellate hairs, dirt particles.

Paratype #2: Female in Baltic amber; no. CCHH #952- 1 in the collection of Christel and Hans Werner Hoffeins , Hamburg, Germany (later to be deposited at the Senckenberg Deutsches Entomologisches Institut , Müncheberg, Germany) ( Fig. 16 View FIGURES 14–17 ). Size of the piece approx. 13 x 7.5 x 7 mm .

Preservation status: The amber is clear, partly pervaded by very few flowlines; the embedded Nebriini fossil is partly covered by milky coating adjoining head and elytra ( Fig. 14 View FIGURES 14–17 ), and extensively covered by milky coating and small bubbles adjoining the ventral surface of the beetle body ( Fig. 15 View FIGURES 14–17 ). Left antennomeres 9–11 and right metatarsomere 5 are cut and thus lost. The fossilized exoskeleton of the specimen is in parts shrunken and thus dissociated from the inclusion wall ( Fig. 19 View FIGURES 18–20 ). However, most details of diagnostic importance of the external morphology could be reconstructed based on both, the remains of the fossilized exoskeleton and the negative imprint of the beetle body on the inclusion wall, using micro-CT ( Figs 18–20 View FIGURES 18–20 , 29 View FIGURES 27–30 ) including the gonocoxites ( Figs 50–53 View FIGURES 42–53 ).

Syninclusions: No syninclusions except for a few dirt particles.

Paratype #3: Female in Baltic amber, deposited in the amber collection of the Senckenberg Deutsches Entomologisches Institut , Müncheberg, Germany ( SDEI) ( Fig. 23 View FIGURES 21–23 ). Size of the piece approx. 24 x 14 x 5 mm .

Preservation status: The amber attached to the embedded Nebriini fossil is pervaded by several flowlines, dorsally and ventrally of the fossil; its ventral surface is almost fully covered by milky coating ( Fig. 22 View FIGURES 21–23 ). Due to the extensive flowlines, micro-CT scans resulted in low contrasts between amber and fossil particularly on its dorsal surface ( Fig. 24 View FIGURES 24–26 ).

Syninclusions: Two Nematocera flies, wing remains of an additional Nematocera fly, stellate hairs, dirt particles.

Description. Color: All specimens appear unicolored dark throughout, with pronotum and elytra markedly shiny. No metallic reflection is evident.

Microsculpture: Not visible on any part of the male holotype, and on the head surfaces of any of the female paratypes; on pronotum and elytra of females with very finely impressed small transverse meshes (visible at magnifications of> 60x).

Measurements: Standardized body length 6.4 (holotype, paratype #1) to 7.2 mm (paratype #3). Length of aedeagal median lobe 0.94 mm (holotype). For additional measurements see Tab. 2 View TABLE 2 .

Proportions, given for holotype; paratype #1; paratype #2; paratype #3:

PW/HW = 1.36; 1.34; 1.41; 1.43.

PW/PL = 1.59; 1.65; 1.62; 1.65.

PW/PWb = 1.03; 1.07; 1.08; 1.13.

PWb/PWa = 1.36; 1.27; 1.28; 1.22.

EW/PW = 1.06; 1.22; 1.18; 1.18.

EL/EW = 1.50; 1.50; 1.46; 1.47.

EL/FL = 2.00; 2.10; 2.05; 2.16.

LPL3/LPL2 (min–max) = 1.21–1.23; 1.19–1.24; not measurable in paratype #2; 1.26–1.28.

EL/AedL = 4.15 (holotype).

Variation: The pronotum is less transverse, and its extension is larger, in the male holotype than in the three female specimens. In the female paratype #3 the pronotum is less constricted towards the base than in the other specimens, and its legs are slightly shorter.

Etymology. The species epithet, inexspectata , is a Latin adjective meaning “unexpected”, referring to unexpected occurrence of a nebriine carabid in Baltic amber.

TABLE 2. Measurements [µm].

  holotype paratype “#1” paratype “#2” paratype “#3”
length of head 939 896 922 1013
width of head 1810 1674 1859 1846
length of pronotum 1547 1363 1624 1603
width of pronotum 2461 2248 2624 2644
pronotal apical width 1762 1694 1899 1922
pronotal basal width 2390 2096 2429 2338
length of left / right elytron 3904 / 3892 4070 / 4117 4483 / 4500 4574 / 4574
width of left / right elytron 1252 / 1345 1381 / 1365 1522 / 1564 1577 / 1544
length of left / right labial palpomere 2 390 / 385 373 / 370 not observable 369 / 370
length of left / right labial palpomere 3 478 / 466 461 / 442 not observable 466 / 476
length of left / right metafemur 1937 / 1949 1935 / 1955 2194 / 2027 2120 / 2070
GPIH

Geologisch-Palaeontologiches Institut der Universitt Haemburg

CA

Chicago Academy of Sciences

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Carabidae

Genus

Archaeonebria

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