New species of belytine and diapriine wasps (Hymenoptera: Diapriidae) from Eocene Baltic amber

. The fossil diversity of Diapriidae in Baltic amber, dated Upper Eocene, has been poorly investigated. However, some studies suggest that this family was already diversified at this time. This is supported by our present study of the Baltic amber collection of the Natural History Museum of Denmark, from which we describe and figure ten new species belonging to the subfamilies Belytinae: Belyta knudhoejgaardi sp. nov., Cinetus breviscapus sp. nov., Cinetus elongatus sp. nov., Pantoclis globosa sp. nov., Pantolyta augustinusii sp. nov., Pantolyta chemyrevae sp. nov., Pantolyta similis sp. nov.; and Diapriinae: Basalys villumi sp. nov., Doliopria baltica sp. nov. and Spilomicrus succinalis sp. nov. The diversity of extant genera observed leads us to propose an origin in the early Cenozoic for these taxa. The fossil record of the Diapriidae in Baltic amber is also summarized. PtW = 0.18 mm), with distinct longitudinal sculpture, and short hairs dorsally; gaster subcylindrical, elongate and tapering at apex (GL = 1.11; GH = ca 0.40 mm); T2 and S2 longest; T2 slightly striated dorsally at junction with petiole; T6 and T7 not clearly separated and forming long triangle; ovipositor exerted, slightly shorter than gaster (OL = 0.89 mm).


Introduction
The Diapriidae Haliday, 1833 are a diverse family of small parasitoid wasps, comprising more than 2000 extant species (Johnson et al. 2021), which corresponds to less than half of the estimated diversity (~ 4500 spp.; Johnson 1992). They occur in all ecozones except the Antarctic but are more abundant in the southern hemisphere and are generally associated with wet forests and marshes, where they live near water or in the soil (Perrichot & Nel 2008). The biology of most species of diapriid wasps is unknown; those from which information is available are mainly pupal endoparasitoids on flies but also on beetles or ants (Loiácono 1987;Masner 1993).
Compared with the extant fauna, studies on fossil Diapriidae are sparse. Perrichot & Nel (2008: appendix 1) summarized the fossil record of the family, showing great contrasts between each of the subfamilies. To date, Ambositrinae are only known from two Cenozoic deposits (Masner 1969;Antropov et al. 2014). On the contrary, more than thirty Belytinae have been documented in various deposits from Quaternary African copal to Albian French amber, making it the most frequently encountered subfamily. Though Belytinae is hypothesized to be sister to the rest of the family (Masner 1993), it does not include the oldest known fossil diapriid, which is the Ismarinae Cretapria tsudakai Fujiyama, 1994 from Aptian Choshi amber (ca 121 Ma; Fujiyama 1994). Another undetermined ismarine is known from Cenomanian French amber (Schlüter 1978). Finally, Diapriinae are almost exclusively known from Cenozoic deposits but one is mentioned from Cenomanian Taimyr amber (Zherikhin & Sukatsheva 1973). Since Perrichot & Nel (2008), very few studies have focused on fossil diapriids: Lak & Nel (2009), Engel et al. (2013), van de Kamp et al. (2018), ,  and Brazidec et al. (2021) described new taxa from Cenomanian French amber (ca 100 Ma), Albian Spanish amber (ca 110 Ma), Paleogene phosphorites of the Quercy Region in France, Late Eocene Baltic amber and mid-Cretaceous Burmese amber (ca 100 Ma), respectively, while Antropov et al. (2014) revised the family from the Eocene of Isle of Wight. In total, around sixty fossils of diapriids have been documented but many specimens are only identified to the genus, subfamily or even family level.
Baltic amber is renowned for being one of the largest amber deposits, at least from the Cenozoic, with Cretaceous Burmese amber rivalling it, and probably the best studied (Poinar 1992;Grimaldi 1996;Weistchat & Wichard 2002). Many studies have been published since Sendel (1742): Penney & Jepson (2014) estimated than more than 3000 species have been described from Baltic amber. Some taxa such as ants (Cheny et al. 2019;Perkovsky 2016) or bees (Engel 2001) have been treated extensively, others are little studied, e.g., many of the parasitoid wasp families. The Diapriidae is one of those: only eight species have been documented, all belonging to Belytinae (Table 1). Maneval (1938) was the first to describe fossil diapriids from Baltic amber, followed by Szabó & Oehlke (1986). Buhl (1999Buhl ( , 2002 described three new species and reported one extant species. Finally, Jouault & Nel (2020) described the latest species. However, these are just a small fraction of the known diapriid diversity in Baltic amber: Buhl (1999Buhl ( , 2002 highlighted the presence of several extant belytine genera (i.e., Aclista Förster, 1856, Belyta Jurine, 1807, Miota Förster, 1856, Pantoclis Förster, 1856and Zygota Förster, 1856 and  Masner (1969) reported numerous undetermined Ambositrinae. Consequently, a closer survey of the existing material is likely to reveal new species.
Here, we study the collection of Diapriidae in Baltic amber pieces of the Natural History Museum of Denmark in order to describe and illustrate ten new species belonging to the Belytinae and Diapriinae. We also summarize the fossil record of Diapriidae in Baltic amber (Table 1).

Amber deposit
The collection of Diapriidae included in Baltic amber pieces from the Natural History Museum of Denmark, 19 inclusions in particular, have been studied. The amber-bearing layer is the Blue Earth Formation which occurs throughout northern Europe just under the sea-level around the Baltic shore (Weistchat & Wichard 2010: fig. 1 Ritzkowski 1997) has been proposed for this formation but this was probably an overestimate (Clauer et al. 2005). Small amounts of amber occasionally occur in older lower layers (Weistchat & Wichard 2010) as well as in Oligocene sediments; these may be redeposited Eocene material (Standke 2008). In this paper, we assume a Priabonian age for Baltic amber (Seyfullah et al. 2018).

Preparation, morphological examination and repository
Amber pieces were polished to facilitate the observation of the specimens using a grinder polisher (Buehler EcoMet 30), a very thin silicon carbide sanding paper (grit size = 7000) and a diamond disk. The specimens were examined and photographed with a Canon EOS 250D attached to a Leica M80 stereo microscope, under incident and transmitted light. All images are digitally stacked photomicrographic composites of several focal planes, which were obtained using HeliconFocus ver. 6.7. Adobe Illustrator CC2019 and Photoshop CC2019 software were used to compose the figures and ImageJ ver. 1.53 for measurements (following the method of Yoder 2004). The description of the characters follows the nomenclature of Masner & García (2002). All the specimens are housed in the amber collection of the Natural History Museum of Denmark (NHMD), University of Copenhagen, Denmark.

Etymology
We dedicate this species to the Knud Højgaard Foundation, who generously contributed to funding for purchasing the amber pieces studied. The specific epithet is to be treated as a noun in genitive case.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.

Male
Unknown.

Comments
Using Nixon's (1957) key, Belyta knudhoejgaardi sp. nov. keys out to Belyta because of the following characters: macropterous, notauli present, mandibles of ordinary form, scutellum without a row of foveae along posterior margin, marginal vein shorter than its distance from basal vein, pronotum elongate, without a hollow on each side (= pronotal pits), epomia present, median keel of propodeum simple, petiole more than one and a half time as long as wide. The flattened body is generally accepted to diagnose Belyta spp. (Macek 1996) and is present in Belyta knudhoejgaardi, strengthening the placement of the species in Belyta.
Following the key to European species of Belyta of Macek (1996), Belyta knudhoejgaardi sp. nov. keys out between B. subclausa Kieffer, 1916 andB. validicornis Thomson, 1858. It differs from the first by having a marked epomia and from the second by having the median propodeal keel simple (Macek 1996). The diagnostic character for Belyta knudhoejgaardi is the curiously marked longitudinal keel on the mesopleuron, which is absent in other species of Belyta. From the Eocene of Florissant is known B. mortuella Brues, 1910 (attributed to Belyta s. lat.), which differs from B. knudhoejgaardi by being shorter and having a less flattened body (Brues 1910 with basal cell open (Fig. 1B); hind tibia and tarsomeres with long recumbent hairs; petiole 2.8 times as long as high, with longitudinal ribs; gaster globose; T2 covering two thirds of gaster; S2 longer than T2 (Fig. 2E).

Etymology
The specific epithet is to be treated as an adjective and is composed of 'brevi-', meaning 'short', and '-scapus', a reference to the small size of the scape.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.
MesosoMa. Shorter than metasoma (MsL = 1.21 mm); pronotum without epomia, only visible in lateral view; mesoscutum smooth; notauli deep, diverging at posterior terminations toward a point outside scutellum; anterior scutellar pit bean-shaped; scutellum without posterior scutellar pits; mesopleuron with epicnemial pit, epicnemial bridge and subalar bridge present; propodeum with prominent plicae; median propodeal keel simple. Fore wing hyaline, uniformly micropubescent (FwL = 3.58 mm); venation complete with C, Sc+R, basal vein, M+Cu, marginal vein, r-rs and Rs pigmented; marginal vein very long, longer than its distance from basal vein and as long as radial cell; postmarginal vein fading after middle of radial cell; Rs proximally directed toward base of wing; M inconspicuous towards apex; Cu short and nebulous; radial cell closed. Hind wing narrow, with C pigmented and basal cell opened (HwL = 2.23 mm). Legs slender, covered with setae; tibial spur formula 1-2-2; hind tibia and tarsomeres with long recumbent hairs.

Female
Unknown.

Comments
Using Nixon's (1957) key, Cinetus breviscapus sp. nov. keys out to Cinetus Jurine, 1807 because of the following characters: mandibles of ordinary form, scutellum without a row of foveae posteriorly, marginal vein very long, notauli slightly divergent posteriorly. Following Nixon's (1957) key to male species of Cinetus, Cinetus breviscapus keys out near C. aletes Nixon, 1957 because of its scape that is shorter than F1 but differs in having the first flagellomere less distinctly longer than the scape (ratio scape length/F1 length: 1.2 vs 1.43; Nixon 1957), the petiole longer (three times as long as wide vs "about two and a half times as long as wide") and being bigger (body length ca 3.6 mm vs ca 2.2 mm). In Baltic amber, Cinetus breviscapus sp. nov. is considered as separate from Cinetus inclusus Maneval, 1938 and Cinetus balticus Szabó & Oehlke, 1986 because it clearly does not fit with their descriptions. The petiole of C. balticus is longer than that of C. breviscapus (ratio length/middle height: 4 vs 2.8) and the fore wing venation is different (C. breviscapus has a longer marginal vein, a longer radial cell, the postmarginal vein does not extend beyond the radial cell and Rs is conspicuous for almost all its length). Cinetus inclusus has a shorter petiole (ratio length/middle height: 1.5) and the scape as long as pedicel, F1 and half of F2 combined, unlike C. breviscapus whose scape is shorter than flagellomere 1.

Etymology
The species name derives from the general elongate aspect of the species. The specific epithet is to be treated as an adjective.

Type material
Holotype NHMD-608402, a complete male but partially hidden by a milky coat.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.

Female
Unknown.

Comments
Using Nixon's (1957) key, Cinetus elongatus sp. nov. keys out near Leptorhaptus Förster, 1865 sensu Nixon (1957) because of the following characters: fourth antennal segment not modified, mandibles of ordinary form, scutellum without a row of foveae along posterior margin, marginal vein hardly shorter than the radial cell, petiole much longer than wide, notauli subparallel, terminates in scutellar hollow. Leptorhaptus is currently regarded as a synonym of Cinetus (Masner 1964). Cinetus elongatus displays all the diagnostic characters of Cinetus provided by Quadros & Brandão (2017), especially the large anterior scutellar pit, the posterior extremity of notauli directed toward a point within the anterior scutellar pit, the marginal vein shorter than radial cell and slightly shorter than its distance to basal vein.
Among the Baltic amber species, it differs from other Cinetus species as follow: C. balticus has the scape as long as F1 (longer in Cinetus elongatus sp. nov.), the petiole shorter (ratio length/middle height: 4 vs 5.3) and the marginal vein longer than its distance from basal vein; Cinetus breviscapus sp. nov. has the scape shorter than F1, the petiole shorter (ratio length/middle height: 2.8), the marginal vein longer than its distance from basal vein and the postmarginal vein shorter than radial cell; C. inclusus has a shorter petiole (ratio length/middle height: 1.5) and a smaller body (1.9 mm).

Etymology
The species name refers to the globular gaster of the species. The epithet is to be treated as an adjective.

Type material
Holotype NHMD-608414, a complete female but partially hidden by a milky coat; paratype NHMD-608394, a complete male.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.
Male BL = 3.50 mm; similar to female but antennae sexually dimorphic: scape shorter than head length (HeL = 0.53 mm), 5.5 times as long as wide, pedicel rounded, as long as wide, 12 flagellomeres elongate, cylindrical, longer than wide, F1 longest, with marked emargination on anterior third of segment, F2-F12 subequal in length, F12 tapering at apex (antennomeres length of male paratype, in mm: Sc-0.

Comments
Using Nixon's (1957) key, Pantoclis globosa sp. nov. keys out to Pantoclis because of the following characters: antennae inserted on a frontal prominence, mandibles not forming a beak or sickle-shaped, notauli present, scutellum without foveae along posterior margin, marginal vein nearly as long as its distance from basal vein and presence of ring-like segments beyond the large tergite, marginal vein shorter than radial cell, epomia distinct, median propodeal keel simple, petiole at most one and a third times as long as its apical width. Pantoclis globosa also fits in Pantoclis according to the diagnosis of . It differs from most extant representatives of Pantoclis by having the marginal vein much longer than the r-rs (Nixon 1957;Sharma 1980;Buhl 1998). Pantoclis longiscapa Chambers, 1974 has a similar fore wing configuration but differs by having F1 very long and F2 distinctly longer than the following flagellomeres (Chambers 1974). Pantoclis deperdita Brues, 1906, from the Eocene of Florissant has a shorter radial cell and marginal vein (Brues 1906) and is therefore considered as a different species from P. globosa.

Etymology
We dedicate this species to the Augustinus Foundation, who generously contributed to the funding for purchasing the amber pieces studied. The specific epithet is to be treated as a noun in genitive case.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.

Female
Unknown.

Comments
Using Nixon's (1957) key to the genera of Belytinae, Pantolyta augustinusii sp. nov. keys out near Acropiesta Förster, 1856 because of the following characters: notauli present, second flagellomere not modified; scutellum without foveae; mandibles not forming a beak; marginal vein shorter than both radial cell and its distance from basal vein; pronotum with reduced epomia; large tergite markedly tapering towards petiole. Pantolyta augustinusii especially share with Acropiesta the antennal shelf prominent with toruli separated by a furrow, the 14-segmented antennae with F1 modified, the pronotal shoulders rounded, the notauli complete, the anterior scutellar pit large and quadrate, the propodeum with median keel simple, the fore wing venation with C, Sc+R, M+Cu, Rs, basal and marginal vein tubular, the petiole cylindrical (Macek 1998). However, due to their close similarities, Acropiesta has recently been synonymized under Pantolyta by Chemyreva & Kolyada (2021). Four other Pantolyta species are present in Baltic amber, two having been described under Acropiesta and not duly transferred by Chemyreva & Kolyada (2021): Pantolyta antiqua Buhl, 1999, Pantolyta janzeni (Buhl, 2002) comb. nov., Pantolyta perrichoti  comb. nov. and Pantolyta somnulenta Maneval, 1938. Pantolyta antiqua has the marginal vein as long as its distance from basal vein whereas it is distinctly shorter in Pantolyta augustinusii (Buhl 1999); P. janzeni has a distinct emargination of F1 in the male antenna, the marginal vein is shorter and the postmarginal vein is longer than in Pantolyta augustinusii (Buhl 2002); P. perrichoti has the median propodeal keel bifid  and P. somnulenta has the radial cell shorter than the marginal vein (Maneval 1938).

Etymology
The species is dedicated to Vasilisa Chemyreva, Russian entomologist, in acknowledgment of her numerous publications on Diapriidae from the Palearctic region. The specific epithet is to be treated as a noun in the genitive case.

Type material
Holotype NHMD-608448, a complete female partially hidden by a milky coat.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.
Among the Baltic amber species, it differs from other Pantolyta species as follow: P. antiqua is macropterous and has F1 more than two times as long as pedicel; Pantolyta augustinusii has the toruli separated by a distinct cleft, the mesoscutum bearing long hairs and the plicae not projecting posteriorly; P. janzeni and P. perrichoti has a longer petiole, more than two times as long as wide; P. somnulenta is very similar to P. chemyrevae sp. nov. but is macropterous, has anterior scutellar pit narrower than P. chemyrevae and the plicae less produced posteriorly.

Etymology
The specific epithet refers to its similarity with the extant species Pantolyta macrocera (Thomson, 1858) and is to be treated as an adjective.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.

Comments
The specimen was originally identified as the extant species Pantolyta macrocera (Thomson, 1858) by Buhl (2002) because of the brachypterous morph. However, we can observe some differences on the petiole and gaster. Pantolyta similis sp. nov. displays numerous fine longitudinal ribs dorsally on the petiole whereas there are fewer ribs in P. macrocera. Additionally, P. macrocera has shorter and stronger medial striations on T2 than Pantolyla similis (Chemyreva & Kolyada 2021: fig. 11g).
Among the Baltic amber species, it differs from other Pantolyta species as follows: P. antiqua and P. somnulenta are macropterous and have a shorter petiole; Pantolyta augustinusii sp. nov. has the epomia present, whereas it is absent in Pantolyta similis sp. nov.; Pantolyta chemyrevae sp. nov. has the epomia present, the anterior scutellar pit more quadrate, the petiole more elongate and the striations on T2 shorter; P. janzeni and P. perrichoti has a longer petiole, more than two times as long as wide.

Etymology
We dedicate this species to Villum Fonden, who generously contributed to funding for purchasing the amber pieces studied. The specific epithet is to be treated as a noun in the genitive case.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.

Female
Unknown.

Comments
Using Nixon's (1980) and Masner & García's (2002) keys, Basalys villumi sp. nov. keys out to Basalys Westwood, 1833 because of the following characters: antenna with 14 segments, notauli absent, scutellum with anterior scutellar pit, wings fully developed, Sc+R separated from fore margin of wing, fore wing with distinct basal vein, basal margin of large tergite straight. The description of the species is also consistent with the diagnosis of .

Etymology
The species name refers to the origin of the amber piece containing the specimen. The specific epithet is to be treated as an adjective.

Type material
Holotype NHMD-608374, a complete female partially hidden by a milky coat.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.
MesosoMa. Slightly shorter than metasoma (MsL = 0.43 mm); pronotum with lateral posterior margin straight; mesoscutum large and slightly convex, without notauli or any other sulci; anterior scutellar pit deep, not divided, suboval; scutellum subquadrate; propodeum minutely punctuate in anterior part and carinate. Fore wing extending beyond metasoma (FwL = 0.77 mm), micropubescent and bordered with short setae; only Sc+R present, slightly separate from anterior margin of wing, distally ending in slight thickening of marginal vein. Hind wing length two thirds of length of fore wing (HwL = 0.55 mm), micropubescent; with long setae along posterior margin and distal part of costal margin; three hamuli present; basal cell open. Legs slender, with only hind coxa and femur stouter; tibial spur formula 1-2-2; tarsal claws simple.

Male
Unknown.

Etymology
The species name derives from 'Succinite', a name given to Baltic amber due to its chemical composition. The specific epithet is to be treated as an adjective.

Locality and horizon
Baltic amber is considered to be of Bartonian-Priabonian age, ca 34-38 Ma.
MesosoMa. Shorter than metasoma (MsL = 0.67-0.83 mm); pronotum not elongate, not visible in dorsal view, laterally with small foveae on posterior margin; mesoscutum wide, flat and smooth, with several long hairs; notauli present, deep, convergent posteriorly but not reaching posterior margin of mesoscutum; anterior scutellar pit bifoveate; scutellum with posterior scutellar pits present; propodeum carinate, with prominent median keel. Fore wing extending beyond gaster (FwL = 1.27-1.81 mm), hyaline and covered with micropubescence, rounded, bordered with long setae shortening toward wing apex; Sc+R pigmented and distinctly separated from wing margin; marginal vein thickening at apex of Sc+R and almost two times as wide as long; r-rs pigmented and elongate, almost as long as marginal vein. Hind wing half as long as fore wing; only C pigmented. Legs slender, with numerous long setae; first fore tarsomere bearing row of erect setae on inner margin; fore tibial spur long, curved; tibial spur formula 1-2-2; first hind tarsomere not longer than following two combined.

Male
Unknown.

Comments
Using Nixon's (1980) and Masner & García's (2002) keys to the genera of Diapriinae, Spilomicrus succinalis sp. nov. clearly keys out to Spilomicrus because of the following characters: antenna with 13 segments, flagellum thickened towards apex, frons unarmed, ocellar triangle in the ocular zone, notauli present, scutellum with an anterior bifoveate pit, wings fully developed, fore wing with pigmented Sc+R, marginal vein not more than one and a half times as long as wide, anterior margin of syntergite straight, without a furrow or a cleft at base.
Following the key to the British species of Nixon (1980) and to Eastern Palaearctic species of Chemyreva (2018), S. succinalis sp. nov. keys out near S. comatus Chemyreva, 2015. It differs from this species by having F11 longer than F10, the petiole less than two times as long as wide and lacking the long hairs on the postgena (Chemyreva 2015).

Discussion
It has been known for 20 years that Baltic amber held a remarkable diversity of fossil Diapriidae (Buhl 1999(Buhl , 2002 but only seven species have been described prior to this study (Table 1). By describing ten new species, the fossil record of the family in this deposit is more than doubled. While specimens belonging to the extant belytine genera Cinetus and Pantolyta were already studied, Belyta knudhoejgaardi sp. nov. and Pantoclis globosa sp. nov. represent the earliest temporal occurrence for these genera. This is also the case for the extant diapriine genera because none of them have previously been recorded as early as the Late Eocene: Basalys villumi sp. nov., Doliopria baltica sp. nov. and Spilomicrus succinalis sp. nov. The other species Cinetus breviscapus sp. nov., Cinetus elongatus sp. nov., Pantolyta augustinusii sp. nov., Pantolyta chemyrevae sp. nov. and Pantolyta similis sp. nov. extend the records for their genera.
However, genera such as Pantolyta and Spilomicrus are represented by numerous specimens of several species that are yet to be described from Baltic amber. Today, these genera are very diverse and widely distributed in the world and it seems that a similar diversity exists in Baltic amber. This means that the current world fauna of Diapriidae had already radiated by the Late Eocene and that earlier representatives of extant taxa can potentially be found in the Paleocene. Thus, it could be interesting to explore older hymenopteran assemblages to elucidate the first phases of the Cenozoic radiation of Diapriidae. The Lutetian Kishenehn formation (USA) and the Ypresian deposits of the Okanagan Highlands (USA-Canada), respectively dated around 46 Ma and 50 Ma, already provided exquisitely preserved Diapriidae, but they have not been studied taxonomically yet (Greenwalt & Labandeira 2013;Archibald et al. 2018). Additionally, there is at least five major deposits, older than Baltic amber, that are likely to yield modern Diapriidae in the Early Paleogene: Oise amber (France), Fushun amber (China) or Cambay amber (India) dated Ypresian around 50-55 Ma, the Fur Formation (Denmark) dated from the Paleocene-Eocene boundary, and the Menat fossil site (France) dated from the middle Paleocene.
Finally, for the twelve genera documented in Baltic amber (Table 1), we see that only two of them show a geographic regression since the Bartonian-Priabonian: Ambositra Masner, 1961 (Ambositrinae) and Doliopria (Diapriinae). Masner (1969) estimated that he was able to observe more than eighty specimens belonging to Ambositra of which one species is very common. This genus is currently recorded in Congo, South Africa and Madagascar (Masner 1969). Today's Doliopria are restricted to the New World, with most species in the Neotropic region (Masner & García 2002). Other genera are cosmopolitan (Aclista, Belyta, Cinetus, Miota: Quadros & Brandão 2017;Pantoclis: Hou et al. 2016;Basalys: Masner & García 2002;Spilomicrus: Chemyreva 2018) or distributed in the Holarctic (Pantolyta: Chemyreva & Kolyada 2019Zygota: Macek 1997). The distribution of Ambositra or Doliopria is probably relictual, probably being correlated with the general cooling of the climate in the last 50 Ma. This pattern with fossil taxa occurring in Baltic amber and the extant fauna in different biogeographic regions is not unique among Hymenoptera with examples in other families, as the Formicidae Latreille, 1809(e.g., Carebara Westwood, 1840, Gesomyrmex Mayr, 1868, Tetraponera Smith, 1852: Perkovsky 2016 or the Megalyridae Schletterer, 1890 (Vilhelmsen et al. 2010b). However, the major proportion of the Diapriidae fauna from Baltic amber lacks tropical affinity, meaning that the current distribution of this family cannot be exclusively explained by climate.