Two new fossil species of Baltocar Kuschel, 1992 and Pseudomesauletes Legalov, 2001 (Curculionoidea:
Rhynchitidae) are described from Eocene Baltic amber. Baltocar sontagae sp. nov. is similar to
B. groehni Riedel, 2012 but differs in the shorter rostrum, tarsomere 1 shorter
than tarsomere 5 and 1.4× as long as tarsomere 2, longer elytra,
and shorter body. Pseudomesauleteslobanovi sp. nov. is similar to P. culex (Scudder, 1893) and P. ibis
(Wickham, 1912): the new species differs from P. culex in the larger eyes, longer
pronotum, being 0.44× shorter than elytra, and slightly smaller body
size; from P. ibis it differs in the smaller body size, rostrum shorter than
elytra, and weakly convex pronotum. This is the first record of
Pseudomesauletes from Baltic amber and the sixth species of Baltocar. Keys to species of the genus
Baltocar and to the Eocene species of the genus Pseudomesauletes are given. Assumed trophic
relationships of these fossil taxa are discussed (urn:lsid:zoobank.org:pub:260EBE6E-DA6C-4D6D-A1D2-2C258224622F).
Introduction
Beetles of the family Rhynchitidae have more than 2000 described species in
the Holocene fauna (Legalov, 2015a). Representatives of this family are
distributed almost everywhere, with the centre of diversity in the tropics
and subtropics (Legalov, 2007). The rhynchitid larvae develop in the dead
parts of the plant, usually gnawed by the female (Legalov, 2004).
Thirty-five species were found in the fossil record (Legalov, 2015b; Bukejs
and Legalov, 2019; Kania and Legalov, 2019). The earliest Rhynchitidae are
known from the Cenomanian of Botswana and the Turonian New Jersey amber
(Gratshev and Zherikhin, 2000; Legalov, 2015b). They are found in the
Paleocene of France (Legalov, 2020b), the Eocene of the USA and Europe
(Legalov, 2015b, 2020b), the Oligocene of Europe (Legalov, 2020b), the
Miocene of Germany (Heer, 1847), and also Dominican and Mexican amber
(Poinar and Brown, 2007; Poinar and Legalov, 2015). Nine rhynchitid species
are described from Eocene Baltic amber (Voss, 1953; Legalov, 2012, 2013,
2015b, 2020a, b; Riedel et al., 2012; Kania and Legalov, 2019). The
extinct genus Baltocar Kuschel, 1992 includes five species (Riedel et al., 2012;
Legalov, 2015b, 2020a). A new species of this genus is discovered in
examined Baltic amber material. The fossil species of the genus
Pseudomesauletes Legalov, 2001 were known from Rovno amber (Bukejs and Legalov, 2019) and
Florissant (Legalov, 2015b). A newly described species is the first record
of this genus from the Baltic amber.
Material and methods
The material examined is deposited in the collection of the Museum of Amber
Inclusions, University of Gdańsk (Poland) (MAIG). The amber pieces were
polished by hand, allowing improved views of the included specimens and
were not subjected to any supplementary fixation.
The photographs of specimens were taken using a Canon 70D camera with a
macro lens (Canon MP-E 65 mm). Extended depth of field at high magnifications
was achieved by combining multiple images from a range of focal planes using
Helicon Focus v. 6.0.18 software, and the resulting images were edited to
create figures using Adobe Photoshop CS5.
The X-ray micro-CT observations of specimen 6703 (MAIG) were conducted at
Daugavpils University, Daugavpils, Latvia (DU), using a Zeiss Xradia 510
Versa system. Scans were performed with a polychromatic X-ray beam at an
energy of 40 kV and power of 3 W. Sample-to-detector distance was set to 17.5 mm, and source-to-sample distance was 47.7 mm. Tomographic slices were
generated from 3001 rotational steps through a 360∘ rotation, using a
4× objective. The exposure time during each projection was set
to 5 s. Acquired images were binned (2×2×2), giving a
voxel size of 4.87 µm. Images were imported into the Dragonfly PRO
(ver. 4.1) software platform for interactive segmentation and 3D
visualization.
Morphological terminology follows Legalov (2007) and Lawrence et al. (2010).
Photomicrographs of Baltocar sontagae sp. nov., holotype, 6703 (MAIG): (a) habitus, left lateral view; (b) details of forebody, lateral view. Scale
bars = 0.25 mm. Abbreviations: a1–a11 denote antennomeres 1–11.
X-ray micro-CT renderings of Baltocar sontagae sp. nov., holotype, 6703 (MAIG),
habitus: (a) dorsal view; (b) dorso-frontal view; (c) left lateral
view. Scale bar = 0.5 mm.
Etymology
Patronymic. This new species is named in honour of our colleague Elżbieta Sontag (Gdańsk, Poland), who provided us the opportunity to
study this interesting fossil specimen.
Type material
Holotype. Collection number “6703” (MAIG) (ex. coll. Jonas Damzen JDC
9012), “Holotype/Baltocar/sontagae sp. nov./Bukejs et Legalov des. 2021” (red
printed label); adult, sex apparently female. A complete beetle included in
a transparent, yellow amber piece with approximate dimensions of 24 mm × 5 mm and a maximum thickness of 4 mm, preserved without
supplementary fixation. The right part of the specimen is partially obscured
by milky amber. Syninclusions: one Brachycera (Diptera) specimen.
Type stratum
A predominantly Bartonian age (41.3–37.9 Ma) is interpreted for the extinct
central European resin-producing forests, which produced the amber that has
eroded out of Eocene Blue Earth layers (Bukejs et al., 2019). However, the
vast majority of Baltic amber derives from the geological amber-bearing
strata of the certainly Priabonian age (37.8–33.9 Ma) (Sadowski et al.,
2017, 2020).
Measurements. Body length (without rostrum) about 2.4 mm, body maximum width 1.1 mm;
rostrum length 0.82 mm, rostrum width basally 0.16 mm, medially 0.12 mm,
apically 0.20 mm; pronotum length 0.7 mm, pronotum maximum width 0.6 mm;
elytra length 1.7 mm, elytra maximum combined width 1.1 mm.
Body. Unicolourous black (as preserved). Pubescence: pronotum with sparse, short,
semierect thin setae; elytra with sparse, short, recumbent to slightly
semierect setae; and ventral side of body with sparse, fine, recumbent
setae.
Head. Forehead flat, with middle furrow; vertex convex, covered with sparse and
fine punctation; temples 0.6× as long as horizontal diameter of one
eye, with sparse and fine punctation. Rostrum rather long, 1.1 times as long
as pronotum, slightly curved (in lateral view), widened apically (in dorsal
view), about 5.1× as long as wide basally, 6.8× as long as
wide medially, and 4.1× as long as wide apically; covered with very
fine and sparse punctures. Compound eyes large, oval, strongly convex,
vertical diameter about 0.7× as horizontal diameter. Maxillary
palpi with four palpomeres.
Antennae. With 11 antennomeres, not geniculate, with distinct three-antennomered club;
moderately long, about 1.2× as long as rostrum, reaching elytral
posterior margin, inserted at base of rostrum; scape cylindrical,
2.4× as long as wide, and almost as long as antennomere 2;
antennomere 2 subcylindrical, about 2.2× as long as wide, as wide
as scape and 1.7× as wide as antennomere 3; antennomeres 3–6
subconical, elongate, 3.3× as long as wide, equal in size and
shape; antennomere 7 conical, about 2.7× as long as wide, slightly
shorter than antennomere 6; antennomere 8 shortest, 2× as long as
wide; antennal club (antennomeres 9–11) about 0.5× as long as
flagellum (antennomeres 2–8); antennomere 9 about 1.1× as long as
wide, dilated apically, about 2.2× as wide as antennomere 8;
antennomere 10 about 1.1× as long as wide, slightly wider than
antennomere 9, slightly dilated apically; antennomere 11 spindle-shaped with
pointed apex, 1.6× as long as wide; relative length ratios of
antennomeres 1–11 equal to 12 : 11 : 10 : 10 : 10 : 10 : 8 : 6 : 8 : 9 : 13.
Pronotum. Bell-shaped, elongate, 1.6× as long as wide at apex,
1.4× as long as wide in middle and at base, widest in posterior
one-fifth, gradually narrowed anteriad; moderately densely covered with
small punctuation; irregularly rugose; disc flat; lateral margins straight,
posterior margin distinctly convex, anterior margin convex in dorsal view.
Scutellum. Minute, subtriangular, poorly visible in studied specimen.
Elytra. Widely oval, elongate, convex, 2.3× as long as wide combined at
anterior margin, 1.5× as long as wide combined medially,
2.0× as long as wide combined in posterior one-quarter, widest
behind middle, 2.4× as long as pronotum; elytral base concave,
distinctly wider than posterior pronotal margin; humeral callus weak;
elytral punctation small and rather dense (punctures at lateral sides
distinctly sparser), forming regular rows, distance between punctures in
rows equal to 0.7–2.0× diameter of puncture, intervals slightly
convex, distance between rows about 2.0–3.5× diameter of puncture.
Thorax. Prohypomera with fine and rather sparse punctation. Pre- and postcoxal
parts of prosternum short, subequal in length. Epipleuron narrow, with fine
punctures. Metaventrite with small punctation at lateral sides; disc convex.
Metepisternum narrow, about 6.3× as long as wide medially; with
fine punctation.
Legs. Rather long, slender. Procoxae conical, located in middle of prosternum;
mesocoxae round; metacoxae oval, transverse, slightly shorter than abdominal
ventrite 1. Femora clavate, slightly swollen in apical portion, covered with
fine, sparse punctation; profemora about 3.7× as long as wide
medially, metafemora about 3.9× as long as wide medially. Tibiae
cylindrical, almost straight (protibiae slightly curved), with sparse and
fine punctures, with fringe of dark spinulae apically, and apparently with
two small apical spurs (distinctly visible on protibiae); protibial about
9× as long as wide medially, metatibia about 6× as long as
wide medially. Tarsi long, slightly shorter than tibiae, metatarsus about
0.8× as long as metatibia; tarsomere 1 elongate, slightly dilated
apically, tarsomere 2 subconical, elongate, tarsomere 3 bilobed, nearly as
long as wide, apical tarsomere subcylindrical, elongate, slightly curved;
metatarsomere 1 about 2.9× as long as maximum wide, shorter than
tarsomere 5 and 1.4 times as long as tarsomere 2, 0.4× as long as
tarsomeres 2–5 combined, metatarsomere 2 about 2.1× as long as
maximum wide, metatarsomere 3 about 1.1× as long as maximum wide,
apical metatarsomere about 5.5× as long as maximum wide; relative
length ratios of metatarsomeres 1–3, 4 subequal to 4 : 3 : 2 : 4. Tarsal claws
strongly divergent, free, simple.
Abdomen. Convex, covered with small and sparse punctation; all sutures distinct,
complete and straight; ventrites 1 and 2 equal in length, ventrite 3 about
0.7× as long as ventrite 2, ventrite 4 about 0.8× as long
as ventrite 3, ventrite 5 smallest, about 0.7× as long as ventrite
4, with widely rounded apical margin; relative length ratios of ventrites
1–5 equal to 6 : 6 : 4 : 3 : 2 (medially).
Note
Sex of examined specimen determined based on micro-CT results. There is no
sclerotized structure resembling aedeagus inside the abdominal cavity;
therefore, the specimen appears to be female.
Comparison
Baltocar sontagae sp. nov. is similar to B. groehni Riedel, 2012 but differs in the shorter rostrum;
tarsomere 1 shorter than tarsomere 5 and 1.4 times as long as tarsomere 2;
longer elytra and shorter body.
Key to the species of the genus <italic>Baltocar</italic>
(according to Riedel et al. (2012) and Legalov (2020a) with modifications)
Elytral punctation irregular. Rostrum shorter or subequal to pronotum (p. 2).
Elytral punctation forming regular rows. Rostrum longer or subequal to
pronotum (p. 3).
Body covered with dense setae. Rostrum slightly curved, subequal to
pronotum (convexus Legalov, 2015b).
Body without distinct pubescence. Rostrum distinctly curved, shorter than
pronotum (subnudus Riedel, 2012).
Pronotum with slightly rounded lateral sides, about 1.1× as long
as wide. Tarsomere 1 about 0.6× as long as tarsomeres 2–5 combined
(hoffeinsorum Riedel, 2012).
Pronotum with subparallel lateral sides (Fig. 2c), 1.4× as long
as wide. Tarsomere 1 about 0.4× as long as tarsomeres 2–5 combined
(p. 5).
Rostrum long, 18.0× as long as wide medially. Tarsomere 1
slightly longer than tarsomere 5 and 1.2× as long as tarsomere 2.
Elytra 1.2× times as long as maximum combined width. Body longer,
2.9 mm (groehni Riedel, 2012).
Rostrum shorter, 6.8× as long as wide medially. Tarsomere 1
shorter than tarsomere 5 and 1.4× as long as tarsomere 2. Elytra
1.5× as long as maximum combined width. Body shorter, 2.4 mm (sontagae sp. nov.).
Remarks
The studied amber specimen possesses the combination of characters
corresponding to the family Rhynchitidae: antennae not geniculate, quite
long ventrites 3 and 4, narrow epipleuron, tarsal claws free at base, not
extended tarsomere 1. Strongly divergent tarsal claws suggest placement in
the subfamily Sayrevilleinae and tarsal claws lacking teeth assignments of
the specimen to the tribe Sayrevilleini. The new species belongs to the
genus Baltocar based on the short precoxal portion of the prosternum and forehead
with middle furrow.
Photomicrographs of Pseudomesauletes lobanovi sp. nov., holotype, 6701 (MAIG), habitus: (a) dorsal view; (b) ventro-lateral view; (c) right lateral view. Scale
bars = 1.0 mm.
Etymology
Patronymic. The name of this new species is dedicated to the memory of the late
Andrey L'vovich Lobanov, known specialist in Cerambycidae and founder of
coleopteran website “Beetles and Coleopterists”
(http://www.zin.ru/animalia/coleoptera/eng, last access: 30 April 2021).
Type material
Holotype: collection number “6701” (MAIG) (ex. coll. Jonas Damzen JDC
9318), “Holotype/Pseudomesauletes/lobanovi sp. nov./Bukejs et Legalov des. 2021” (red printed
label); adult, female. A complete beetle included in a transparent, yellow
amber piece with approximate dimensions of 33 mm × 11 mm and a
maximum thickness of 7 mm; preserved without supplementary fixation.
Syninclusions: one Diptera specimen, body parts (legs and wing) of cf.
Diptera, few stellate trichomes, and some small gas vesicles.
Type stratum
A predominantly Bartonian age (41.3–37.9 Ma) is interpreted for the extinct
central European resin-producing forests, which produced the amber that has
eroded out of Eocene Blue Earth layers (Bukejs et al., 2019). However, the
vast majority of Baltic amber derives from the geological amber-bearing
strata of the certainly Priabonian age (37.8–33.9 Ma) (Sadowski et al.,
2017, 2020).
Measurements. Body length (without rostrum) about 3.3 mm, body maximum width 1.4 mm;
rostrum length 1.9 mm, rostrum width basally 0.3 mm, medially 0.2 mm,
apically 0.3 mm; pronotum length 1.0 mm, pronotum maximum width 0.9 mm;
elytra length 2.2 mm, elytra maximum width 1.4 mm.
Body. Brown (as preserved), head and rostrum dark brown. Pubescence: rather
dense, short and recumbent.
Head. Dorsally covered with small, sparse punctation, distance between punctures
about 0.5–1.5 × diameter of one puncture, ventrally with sharp
transverse wrinkles and very sparse punctation; forehead wide, convex;
vertex slightly impressed. Rostrum very long, about 1.9× as long as
pronotal length, almost straight (in lateral view), widened to apex (in
dorsal view), about 6× as long as wide basally, 9.5× as
long as wide medially, and 6× as long as wide apically; sparsely
covered with fine punctures, punctation denser in basal portion; with
longitudinal carina in basal one-third of rostral length. Rostral
pleurostomal sinus deep and membranous. Mandibles externally dentated.
Maxillary palpi four-articled. Gular suture single. Compound eyes rather large,
subspherical, strongly convex.
Antennae. With 11 antennomeres, not geniculate, with distinct three-antennomered club;
moderately long, about 0.7× as long as rostrum length, reaching
anterior one-third of pronotum, inserted in basal one-third of rostral
length, sparsely covered with semierect setae; scape cylindrical,
2× as long as wide, 0.6× as long as antennomere 2,
antennomeres 2–6 elongate-oval, antennomere 3 about 1.3× as long
as antennomere 2, antennomeres 7–8 short, slightly dilated apically,
antennal club about as long as antennomeres 5–6 combined, antennomere 9 as
long as wide, dilated apically, wide, about 2× as wide as
antennomere 8; antennomere 10 slightly transverse, dilated apically, wide,
antennomere 11 elongate oval with tapered apex; relative length ratios of
antennomeres 1–11 equal to 7 : 11 : 14 : 11 : 9 : 6 : 5 : 3 : 5 : 5 : 7.
Pronotum. Nearly as long as wide, widest medially, narrowed posteriad and anteriad;
densely covered with small punctation (punctures distinctly larger than
punctures of head), distance between punctures about 0.3–1.1×
diameter of one puncture (punctation on disc sparser); disc evenly convex;
lateral margins convex medially and subparallel anteriorly and posteriorly,
posterior margin straight, anterior margin convex in dorsal view.
Scutellum. Subpentagonal with widely rounded apex, transverse, about 1.25×
as wide as long, rather large, densely covered with fine punctation.
Elytra. Almost rectangular, elongated, widest behind middle, convex, not ribbed,
in anterior one-third slightly impressed medially; elytral base distinctly
wider than posterior pronotal margin; humeral callus weak; elytral
punctation small and dense, forming regular rows (distinct in basal half),
intervals flat; elytral apices rounded together, without large depressed
spots and hair stains.
Thorax. Prohypomera with small, dense punctation (as pronotal punctation).
Epipleuron narrow. Metaventrite and metepisternum with fine and very dense
punctation.
Legs. Long, slender. Femora spindle-shaped, slightly flattened, covered with
fine, sparse punctation. Tibiae cylindrical, almost straight, slightly
dilated distally, with fringe of dark spinula apically, lacking costate
dorsal margin. Tarsi distinctly shorter than tibiae, protarsus about
0.5× as long as protibial length; tarsomere 1 trapezoidal,
elongate, not extended, tarsomere 2 trapezoidal, distinctly dilated
apically, tarsomere 3 wide, deeply bilobed, with dense setation ventrally,
terminal tarsomere elongated, subcylindrical, slightly curved. Tarsal claws
slightly divergent, free, with long spine basally.
Abdomen. Convex, covered with small punctation; ventrites almost homonomous;
ventrites 1–3 fused; ventrite 2 1.4× as long as ventrite 1;
ventrite 3 subequal to ventrite 2 and 2.1× as long as ventrite 4;
ventrite 4 about 1.7× as long as ventrite 5; ventrite 5 smallest,
with rounded apical margin.
Note
The specimen is a female: elytral apex lacks hair stains, and abdominal
ventrites 1–3 are fussed.
Comparison
Pseudomesauletes lobanovi sp. nov. is similar to the North American Eocene species P. culex (Scudder, 1893)
and P. ibis (Wickham, 1912), in the long rostrum, almost equal to the length of
the elytra. The new species differs from P. culex in the large eyes; longer
pronotum, 0.44× shorter than elytra (0.25× shorter than
elytra in P. culex); and slightly smaller body size. It differs from P. ibis in the
small body size, rostrum shorter than elytra, and weakly convex pronotum.
Additionally, the new species differs from P. groehni Bukejs et Legalov, 2019 from
Rovno amber in the long rostrum and narrower antennae club.
Key to the Eocene species of the genus <italic>Pseudomesauletes</italic>
Rostrum 1.4 times as long as elytra. Body large, 7.0 mm. Florissant (ibis (Wickham, 1912)).
Rostrum shorter than elytra. Body less than 6.1 mm (p. 2).
Rostrum longer, 0.92–0.96× shorter than elytra (p. 3).
Rostrum shorter, 0.58–0.85× shorter than elytra (p. 4).
Eyes large. Pronotum 0.44× as long as elytra. Body length 3.3 mm. Baltic amber (lobanovi sp. nov.).
Eyes small. Pronotum 0.25× as long as elytra. Body length 4.2 mm.
Florissant (culex (Scudder, 1893)).
Rostrum longer, 0.85× shorter than elytra. Body large (6.1 mm).
Florissant (obliquus (Wickham, 1913)).
Rostrum shorter, 0.57–0.58× shorter than elytra. Body smaller,
3.2–4.9 mm (p. 5).
Body larger, 4.9 mm. Rostrum 4.0× as long as wide apically.
Florissant (striaticeps (Wickham, 1911)).
Body smaller, 3.2 mm. Rostrum 6.25× as long as wide apically.
Rovno amber (groehni Bukejs et Legalov, 2019).
Remarks
The studied amber specimen belongs to the family Rhynchitidae based on the
not geniculate antennae, single gular suture, narrow epipleuron, four-articled
maxillary palpi, ventrites 2 and 3 subequal in length, not extended
tarsomere 1, tarsal claws free at base, and deep and membranous rostral
pleurostomal sinus. Slightly divergent tarsal claws suggest its placement in
the subfamily Rhynchitinae and externally dentated mandibles – in the
supertribe Rhynchititae. Rounded apex of the elytra when both together
confirm the assignment of the species to the tribe Auletini. The new species
belongs to the subtribe Pseudomesauletina based on the tarsal claws with a
spine, tibia lacking costate dorsal margin and antennae being inserted
before middle of the rostrum. The body is covered with short sparse
recumbent setae, elytra are not ribbed, elytral apices are without large
depressed spots, antennomere 3 is longer than antennomere 2, antennae are
inserted before the middle of the rostrum, and eyes are strongly convex,
which suggest placement in the genus Pseudomesauletes. The specimen was assigned to the
subgenus Pseudomesauletess. str. on the basis of the almost rectangular elytra and the brown
body colouration.
Distribution of Sayrevilleinae: Minurini (green shaded area),
Vossicartini (yellow shaded area), and Sayrevilleini: six species of
Baltocar from Eocene Baltic amber (black dot), Sayrevilleus grimaldii Gratshev et Zherikhin, 2000 from
Late Cretaceous amber of New Jersey (black triangle), and Orapauletes cretaceus Legalov, 2009
from Late Cretaceous formation of Botswana (black square).
Distribution of the genus Pseudomesauletes with extant (green area) and fossil
records: records from Florissant formation, Colorado, USA (black square);
record from Rovno amber (black octagon); and P. lobanovi sp. nov. from Baltic amber
(black dot).
Discussion
The fauna of the Eocene Rhynchitidae is rather diverse and tribes
Sayrevilleini, Auletini, Rhynchitini, and Eugnamptini are found in its
deposits (Legalov, 2020b). The subfamily Sayrevilleinae is represented by
three tribes (Legalov, 2015a, 2018). Recent Minurini Legalov, 2003 and
Vossicartini Legalov, 2003 are distributed in Chile, Argentina, and Africa
(Legalov, 2007, 2018). The Sayrevilleini is an extinct tribe and known from
fossils only (Fig. 4). The genus Baltocar is found in Eocene Baltic amber but not
found in other Paleogene deposits (Legalov, 2020b). The closely related
genus Sayrevilleus Gratshev et Zherikhin, 2000, which is very close to it, was described
from the Late Cretaceous amber of New Jersey. The genus Orapauletes Legalov, 2009 was
described from the Turonian lacustrine, Orapa, Cretaceous of Botswana. Due
to the absence of the recent representatives of the tribe Sayrevilleini, the
trophic links of its representatives are difficult to determine. It is
habitually similar to the recent genera of the subtribe Auletina, which
develops on Juniperus and Cupressus (Legalov, 2002). Juniperus are recorded in New Jersey and Baltic
amber (Czeczott, 1961; Grimaldi and Nascimbene, 2010). Cupressus is found in Baltic
amber (Czeczott, 1961; Alekseev, 2018). Six rather similar species of
Baltocar inhabiting the same area were probably associated with different plants.
Fourteen species of Cupressaceae are known from Baltic amber (Sadowski et
al., 2017; Alekseev, 2018). It can be assumed that extinct representatives
of the genus Baltocar were associated with them.
The genus Pseudomesauletes (Rhynchitinae, Auletini) is distributed in East and South Asia,
the Zonda Islands, Africa, Madagascar, North America, and Colombia (Legalov,
2007, 2018), but it is absent in Western Palearctic (Fig. 5). Fossil
records are known from the Florissant Formation, Colorado, USA (Scudder, 1893;
Wickham, 1912), and Rovno amber (Bukejs and Legalov, 2019). The newly
described extinct species from Eocene Baltic amber, P. lobanovi sp. nov., belongs to
the species group with the long rostrum almost equal to or longer than the
elytra. In the Holocene fauna, such species are absent but are recorded in
the Eocene deposit of North America (Legalov, 2015b, 2020b). The trophic
relationships of most recent Pseudomesauletes species are unknown (Legalov, 2003).
Pseudomesauletesuniformis (Roelofs, 1874) develops in flower buds of Rosa (Lee and Morimoto, 1988), and
P. formosanus (Voss, 1921) was recorded on Rubus and Rosaceae (Voss, 1934). Fossil species
of Pseudomesauletes were probably related to the family Rosaceae as well, as they quickly
differentiated in the Eocene (DeVore and Pigg, 2007) and are found in Baltic
(Czeczott, 1961; Weitschat and Wichard, 2002) and Rovno amber (Sokoloff et
al., 2018) and in the deposits of Florissant (Manchester, 2001).
Data availability
All material included in this paper is deposited in the Museum of Amber
Inclusions, University of Gdańsk, Poland, and all data are included in
the description. X-ray microtomography volume renderings of the habitus,
habitus of Baltocarsontagae sp. nov., holotype, 6703 (MAIG) an available as a Video
Supplement.
Video supplement
Volume renderings of X-ray microtomography of the habitus of Baltocarsontagae, holotype,
6703 (MAIG). The video is available at
10.5446/51994 (Bukejs and Legalov, 2021).
Author contributions
AB and AAL designed the study, drafted the manuscript, and contributed to
the writing and discussion. AB prepared new species descriptions and plates.
AAL corrected new species descriptions and performed new systematic taxa
placement.
Competing interests
The authors declare that they have no conflict of interest.
Acknowledgements
The authors are sincerely grateful to Elżbieta Sontag (Museum of
Amber Inclusions, University of Gdańsk, Poland) for the loan of
interesting fossil specimens, to Kristaps Kairišs (Daugavpils
University, Daugavpils, Latvia) for assistance in X-ray micro-computed
tomography, and to Jonas Damzen (Vilnius, Lithuania) for assistance
during our amber research and permission to use photographs of studied
specimens. We thank Leonid A. Friedman (Tel Aviv University, Israel) and
Vitalii I. Alekseev (Kaliningrad Regional Amber Museum, Russia) for
their helpful comments and corrections to an earlier version of this
paper.
Review statement
This paper was edited by Carolin Haug and reviewed by Leonid Friedman and Vitalii Alekseev.
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