Research Article |
Corresponding author: Alexandr P. Rasnitsyn ( rasna@online.ru ) Corresponding author: Taiping Gao ( tpgao@cnu.edu.cn ) Academic editor: Brendon Boudinot
© 2025 Zhen Wang, Alexandr P. Rasnitsyn, Evgeny E. Perkovsky, Lars Vilhelmsen, Taiping Gao.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Wang Z, Rasnitsyn AP, Perkovsky EE, Vilhelmsen L, Gao T (2025) New wasps of †Falsiformicidae from mid-Cretaceous Kachin amber. Journal of Hymenoptera Research 98: 1-18. https://doi.org/10.3897/jhr.98.136200
|
Two new species of the family †Falsiformicidae Rasnitsyn, 1975, Siccibythus robustus sp. nov. and Siccibythus aristovi sp. nov., are described from the mid-Cretaceous Kachin amber based on three well-preserved specimens. The new species belongs to †Siccibythus Cockx & McKellar, 2016, based on the elongate pronotum and fore wing with cells 2+3rm and 3r not enclosed with tubular veins. We summarize the diversity and distribution for all species of †Falsiformicidae and provide a revised key to the family. These new findings enhance the diversity of †Falsiformicidae in Kachin amber.
Cenomanian, Kachin amber, key to genera and species, morphological characters, new species
In recent years, a large number of insect species have been discovered in Kachin amber (
†Falsiformicidae Rasnitsyn, 1975 is a small extinct family characterized by a 12-segmented antenna in female, a 13-segmented antenna in male; the hind wing without closed cells; and a node-like first metasomal tergum. The family and its first species, †Falsiformica cretacea Rasnitsyn, 1975, were described in upper Cenomanian amber from Nizhnyaya Agapa in the Taimyr from incomplete male and female specimens, considered to be of the same species (
Species | Locality | Horizon | References |
---|---|---|---|
Falsiformica cretacea | Nizhnyaya Agapa, Taimyr Peninsula, N. Siberia | ?upper Cenomanian |
|
Falsiformix pedestris | Myanmar, Hukawng Valley | lowermost Cenomanian |
|
Neophenax orcus | USA, New Jersey | Turonian amber |
|
Siccibythus aristovi sp. nov. | Myanmar, Hukawng Valley | lowermost Cenomanian | Present study |
Siccibythus martynovae | Myanmar, Hukawng Valley | lowermost Cenomanian |
|
Siccibythus musculosus | Myanmar, Hukawng Valley | lowermost Cenomanian |
|
Siccibythus oculatus | Myanmar, Hukawng Valley | lowermost Cenomanian |
|
Siccibythus ohmkuhnlei | Myanmar, Hukawng Valley | lowermost Cenomanian |
|
Siccibythus pallidus | Myanmar, Hukawng Valley | lowermost Cenomanian |
|
Siccibythus paulus | Myanmar, Hukawng Valley | lowermost Cenomanian |
|
Siccibythus robustus sp. nov. | Myanmar, Hukawng Valley | lowermost Cenomanian | Present study |
Herein, we describe two new species, †Siccibythus robustus sp. nov. and †Siccibythus aristovi sp. nov., from mid-Cretaceous Kachin amber. We provide some diversity statistics, as well as a revised key to the genera and species in †Falsiformicidae. These new discoveries enrich the diversity of the family found in Kachin amber.
The Kachin amber specimens CNU-HYM-MA-2016212, CNU-HYM-MA-2016213 and CNU-HYM-MA-2016214, were purchased by Mr. Fangyuan Xia on September 1, 2014, and donated to the Key Laboratory of Insect Evolution and Environmental Changes, College of Life Sciences, Capital Normal University, Beijing, China, in September 2014. The fossils were all collected in full compliance with the laws of Myanmar and China. All specimens are permanently deposited in well-established, public museums (Key Laboratory of Insect Evolution and Environmental Changes, College of Life Sciences, Capital Normal University, Beijing, China), in full compliance with the International Code of Zoological Nomenclature and the Statement of the International Palaeoentomological Society (
The amber specimens were examined under a Leica M205C dissecting microscope. Photographs were taken with a Nikon SMZ 25 microscope with an attached Nikon DS-Ri2 digital camera system. The wing venation terminology follows that of
The measurements follow
Total body length *. Maximum length from the anterior head capsule to the distal end of the last metasomal segment.
Head length *. Maximum between two vertical parallel lines in the lateral view of the head: one at the anterior margin near the eyes and the other at the posterior margin of the occiput.
Head width. Maximum width of head capsule behind the eyes, in full-face view.
Head height. Maximum length of head capsule, excluding mandibles, measured from anterior margin of clypeus to nuchal carina, with both in same plane of focus.
Scape length. Maximum length of the scape excluding basal constriction.
Pedicel length *. Maximum length of the pedicel.
The first flagellum length *. Maximum length of the the first flagellum.
Total flagellum length *. Combined length of all flagellar segments.
Wing length *. Maximum length of the wing base to margin.
Leg segments length *. Maximum length from the apex to the base of each segment of legs.
The first metasomal segment length *. Maximum length of the first metasomal tergum measured with anterior and posterior margins in same plane of focus.
Metasoma length *. Maximum length from the base of the first metasomal segment to the last metasomal apex, excluding the genitalia in males and the sting in females.
†Falsiformica Rasnitsyn, 1975.
†Falsiformica Rasnitsyn, 1975, †Siccibythus Cockx & McKellar, 2016, †Neophenax Engel, 2022, Falsiformix Zhang & Rasnitsyn, 2024.
Siccibythus musculosus Cockx & McKellar, 2016.
Siccibythus musculosus Cockx & McKellar, 2016, S. martynovae Rasnitsyn, Zhang, Müller& Zhang, 2020, S. oculatus Rasnitsyn, Zhang, Müller & Zhang, 2020, S. ohmkuhnlei Rasnitsyn, Zhang, Müller & Zhang, 2020, S. pallidus Rasnitsyn, Zhang, Müller & Zhang, 2020, S. paulus Rasnitsyn, Zhang, Müller & Zhang, 2020, S. aristovi sp. nov. and S. robustus sp. nov.
Propodeum weakly sculptured with longitudinal carinae; antenna with 13 segments in male, 12 in female, scape elongate and flattened, pedicel weakly pyriform; three or four labial palpomeres; fore wing with no cells closed with tubular veins in its middle and distal part, vein 1m-cu at most only partially tubular; vein R1 absent apical to pterostigma, and apical parts of M, M+Cu and A (distally of Cu-a) spectral. Fore tarsus and mid tarsus with large, bilobed arolium, smaller arolium present on hind tarsus, claws simple.
†Siccibythus Cockx & McKellar, 2016 differs †Falsiformica Rasnitsyn, 1975 and †Neophenax Engel, 2022 by having fore wing with vein 1m-cu at most partially tubular and pronotum with dorsal surface longer than wide or, rarely, subquadrate. †Siccibythus Cockx & McKellar, 2016 differs from †Falsiformix Zhang & Rasnitsyn, 2024 in having a fore wing longer than mesosoma.
The length of the scape is less than 0.3 times the length of the flagellum. Fore wing with 2Rs distal of r-rs several times as long as r-rs; Cu nebulous. Fore tibial spur long, thin and acute apically. Metabasitarsus longer than tarsomeres 2–4 combined. Propodeum outline angular. Anterior outline of 1st metasomal tergum somewhat angular.
The species is named after the Latin adjective robustus, meaning “thick” and referring to the thick fore femur.
Holotype
• female. No. CNU-HYM-MA2016212. A well-preserved and complete specimen (Figs
The amber specimens were collected from Kachin, northern Myanmar, lowermost Cenomanian, mid-Cretaceous, which was dated at 98.79 ± 0.62 Ma (
Female. Head globose, with eyes bulging, occupying most of lateral parts of head (except for wide, convex temples), almost reaching mandibular bases, occipital carina complete, reaching hypostomal carina well behind mandibular base, vertex and frons narrow, longer than wide, ocelli in small acute triangle well distant from eyes, interantennal space flat, clypeus short, simple. Antenna slender, with 12 antennomeres in female (13 in male), each antennomere is approximately 1–2 times longer than wide, scape slightly longer than pedicel and first flagellomere combined, pedicel longer than first flagellomere, flagellomeres slightly shortening gradually toward apex except for shorter first flagellomere and longer apical segment (Fig.
Pronotum posterior margin extended, with pronotum accounting for 0.4 times the length of mesosoma, pronotum short declivitous part delimited by transverse groove posteriorly. Propleura long, slender, abutting throughout ventrally. Mesoscutum convex between notauli; notauli complete, parapsides and lateral edges incomplete; notauli widely spaced anteriorly, converging to almost meet posteriorly; transscutal articulation distinct; mesoscutellum triangular, narrow, the length is 0.4 times its maximum width, weakly convex, carinate laterally. Meso- and metapleuron smooth, metapleuron delimited from propodeum with incomplete row of pits (Fig.
Fore wing distal of basal veins (1Rs and 1M), r-rs and 1cu-a without tubular veins, except for pterostigma and half section of 2Rs distal of r-rs, all other distal veins nebulous in female (fore wing distal of basal vein (1Rs and 1M) and cu-a with no tubular veins, except for pterostigma, r-rs and most of Rs distal of r-rs, all other veins nebulous in male). Pterostigma prominent, longer than wide; vein 1Rs straight, shorter than 1M, arise from Sc+R just proximal to pterostigma; 1cu-a shorter than 1M, placed distinctly before it, parallel to 2cu-a; Cu parallel to A; vein A extending distal to 1cu-a, and distal part tubular, extending distal to 2cu-a as nebulous vein, both 1cu-a and 2cu-a reaching A; r-rs slightly curved, arising beyond midlength of pterostigma; r-m not present (Fig.
Fore coxa swollen, triangular, nearly as long as wide; fore trochanter short, fore trochantellus not visible in female (fore trochantellus trapezoidal, the ratio compared to the length of the fore femur is approximately 1:17 in male); fore femur swollen in middle, twice as long as wide (calcar long, thin, gently curved and acute apically in male); fore tibia nearly as long as femur; fore tarsus shorter than fore tibia, basitarsomere shorter than combined length of remaining tarsomeres in female (basitarsomere longer than combined length of remaining tarsomeres in male). Mid coxa slender, smaller than both fore and hind coxa, twice as long as wide; mid trochanter short, mid trochantellus very short and ring-like, approximately 0.1 times as long as femur; mid femur swollen in middle, twice as long as wide; mid tibia slenderer than femur, three times as long as wide, tibia shorter than femur; mid tarsus nearly as long as mid tibia, basitarsomere shorter than combined length of remaining tarsomeres. Hind coxae elongate, swollen, three times as long as wide, with lamella dorsally, basally in female (no lamella in male); hind trochanter short, bulging dorsally, hind trochantellus very short and ring-like (ca. 0.02 as long as femur); hind femur swollen in middle, nearly three times as long as wide in female (nearly six times as long as wide in male); hind tibia very slender, slightly longer than femur; hind tarsus nearly as long as hind tibia, basitarsomere slightly shorter than combined length of remaining tarsomeres (Fig.
First metasomal segment short, tergum node-like, female with anterior outline, low triangular, second metasomal segment longest and highest, following segments gradually smaller, apical metasomal sternum high, with dorsal sides overlapping (Fig.
Holotype female. Total body length (excluding sting and antenna) 3.93; head length 0.47, width 0.61, height 0.53; scape length 0.25, pedicel length 0.13, the first flagellum length 0.08, total flagellum length 0.87; fore wing length 2.22; hind wing length 1.56; fore coxa length 0.30, fore trochanter length 0.57, fore femur length 0.58, fore tibia length 0.55, fore tarsal length 0.32; mid coxa length 0.31, mid trochanter length 0.09, mid trochantellus 0.05, mid femur length 0.50, mid tibia length 0.38, mid tarsal length 0.38; hind coxa length 0.44, hind trochanter length 0.14, hind trochantellus 0.02, hind femur length 0.67, hind tibia length 0.78, hind tarsal length 1.02; the first metasomal segment length 0.28, metasoma length 2.18.
Paratype male. Total body length (excluding antenna) 3.54; head length 0.50, width 0.42, height 0.50; scape length 0.25, pedicel length 0.16, the first flagellum length 0.09; total flagellum length 0.99; fore wing length 1.98; hind wing length 1.47; fore coxa length 0.21, fore trochanter length 0.08, fore trochantellus 0.03, fore femur length 0.50, fore tibia length 0.45, fore tarsal length 0.32; mid coxa length 0.12, mid trochanter length 0.10, fore trochantellus 0.02, mid femur length 0.40, mid tibia length 0.30, mid tarsal length 0.34; hind coxa length 0.28, hind trochanter length 0.12, hind femur length 0.55, hind tibia length 0.60, hind tarsal length 0.57; the first metasomal segment length 0.25, metasoma length 1.62.
The new species is classified in †Siccibythus Cockx & McKellar, 2016 based on the fore wing with no cells closed with tubular veins in its middle and distal part (
Fore wing with 2Rs distal of r-rs at most about as long as r-rs; Rs+M and Cu both nebulous; A behind 1cu-a not pigmented (except for very base). Fore tibial spur short, bifid apically. Basitarsus not longer than tarsomeres 2–4 combined. Pronotum short, propodeal horns long.
The specific name “aristovi” is dedicated to the memory of the late Dr. Daniil Sergeevich Aristov, for his outstanding contribution to palaeoentomology.
Holotype
• female. No. CNU-HYM-MA2016214. A well-preserved and complete specimen (Figs
The amber specimen was collected from Kachin, northern Myanmar, lowermost Cenomanian, mid-Cretaceous, which was dated at 98.79 ± 0.62 Ma (
Female. Body brown, metasoma dark brown. Head globose, with eyes bulging, occupying three-quarters of head in lateral view, almost reaching mandibular bases, occipital carina complete, reaching hypostomal carina well behind mandibular base, ocelli in small acute triangle well distant from eyes, interantennal space flat. Antenna narrow, with 12 antennomeres, each antennomere is approximately 1–2 times longer than wide, scape shorter than pedicel, pedicel longer than first flagellomere, flagellomeres slightly shortening gradually toward apex except for longer apical segment (Fig.
Pronotum with long dorsal part shorter than wide before lateral lobes, constricted near midlength, with fore declivitous part short, delimited by transverse groove posteriorly. Propleura long, slender, in lateral view, the length is 4 times its width, and abutting throughout. Mesoscutum with deep notauli widely spaced anteriorly, converging to almost meet posteriorly; transscutal articulation distinct; mesoscutellum rather short, wide apically, weakly convex. Meso- and metapleurae smooth. Metanotum short, with metascutellum very short and wide. Propodeum with dorsal and posterior surfaces meeting in angle, dorsal with longitudinal carina, and with transverse one midway between sublateral carinae, posterior surface with lateral longitudinal carinae, sublateral longitudinal carinae and supracoxal transverse carinae (Fig.
Fore wing basal veins (C, Sc+R, M+Cu, A, 1Rs and 1M), r-rs, short pterostigma, part of 2Rs distal of r-rs and cu-a tubular, other veins nebulous. Pterostigma prominent, longer than wide; vein 1Rs straight, shorter than 1M, arise from Sc+R just proximal to pterostigma; 1cu-a shorter than 1M, parallel to 2cu-a, placed slightly basally of 1M; 1Cu parallel to A; vein A extends distal up to 1cu-a only; r-rs straight, arising beyond midlength of pterostigma; r-m not present (Fig.
Fore trochanter present, fore trochantellus ring-like; fore femur slightly swollen in middle, nearly three times as long as wide; fore tibia shorter than femur, calcar acute (not bifid); fore tarsus shorter than fore tibia, basitarsomere shorter than combined length of remaining tarsomeres. Mid trochanter present, mid trochantellus ring-like; mid femur slightly swollen in middle, four times as long as wide; mid tibia nearly as long as femur, six times as long as wide; mid tarsus shorter than mid tibia, basitarsomere shorter than combined length remaining tarsomeres. Hind trochanter short, bulging dorsally, hind trochantellus ring-like; hind femur slightly swollen in middle, nearly four times as long as wide; hind tibia slender than femur, longer than femur; hind tarsus nearly as long as hind tibia, remaining tarsomeres combined shorter than basitarsomere. Claw simple, arolium small. Tibial spur formula 1/2/2.
First metasomal segment short, tergum node-like, triangular in lateral view, with anterior surface concave, second segment slightly longer and higher than following, following gradually smaller, apical (sixth) sternum high, apparently folded, with upper sides and apical orifice apparently not specialized, tergum 7 as visible (in lateral view) small but more or less sclerotized, with spiracle not enlarged (Fig.
Holotype female. Total body length (excluding sting and antenna) 4.14; head length 0.94, width 0.62, height 0.48; scape length 0.20, pedicel length 0.19, the first flagellum length 0.14, total flagellum length 1.11; fore wing length 1.95; hind wing length 1.20; fore coxa length 0.27, fore trochantellus 0.06, fore femur length 0.64, fore tibia length 0.49, fore tarsal length 0.64; mid coxa length 0.25, mid trochanter length 0.10, mid trochantellus 0.04, mid femur length 0.60, mid tibia length 0.64, mid tarsal length 0.39; hind coxa length 0.23, hind trochanter length 0.10, hind trochantellus 0.06, hind femur length 0.69, hind tibia length 0.58, hind tarsal length 0.79; the first metasomal segment length 0.29, metasoma length 1.66.
The new species is classified in †Siccibythus Cockx & McKellar, 2016 based on the fore wing with no cells closed with tubular veins in its middle and distal part (
1 | Brachypterous, with forewing about as long as mesosoma | Falsiformix pedestris Zhang & Rasnitsyn, 2024 |
– | Macropterous, having a fore wing longer than mesosoma | 2 |
2 | Fore wing with 1m-cu completely tubular ( |
3 |
– | Fore wing with 1m-cu at most partially tubular; pronotum with dorsal surface longer than wide or, rarely, subquadrate | 4 |
3 | Pedicel shorter than 1st flagellomere; fore wing with 2-A not developed; metapleuron and propodeum delimited with carina | Falsiformica cretacea Rasnitsyn, 1975 |
– | Pedicel longer than 1st flagellomere ( |
Neophenax orcus Engel, 2022 |
4 | 2Rs distal of r-rs several times as long as r-rs; metabasitarsus longer than tarsomeres 2–4 combined | 5 |
– | 2Rs distal of r-rs at most about as long as r-rs (Fig. |
8 |
5 | Cu well pigmented (Fig. 8C); 1st metasomal segment with long narrow part before node, making up more than one-third of its length | Siccibythus musculosus Cockx & McKellar, 2016 |
– | Cu scarcely or not at all pigmented (Fig. |
6 |
6 | Scape at least 0.3 times as long as total length of flagellum ( |
Siccibythus paulus Rasnitsyn, Zhang, Müller & Zhang, 2020 |
– | Scape distinctly shorter, less than 0.3 times total length of flagellum ( |
7 |
7 | Anterior outline of 1st metasomal tergum straight; propodeum outline smoothly curved ( |
Siccibythus ohmkuhnlei Rasnitsyn, Zhang, Müller & Zhang, 2020 |
– | Anterior outline of 1st metasomal tergum somewhat angular, propodeum outline angular (Fig. |
Siccibythus robustus sp. nov. |
8 | Fore wing length 3.5 mm; Rs+M and Cu distinctly pigmented ( |
Siccibythus martynovae Rasnitsyn, Zhang, Müller & Zhang, 2020 |
– | Fore wing length 2.5 mm or less; Rs+M and Cu not pigmented (Fig. |
9 |
9 | Fore wing with 2-A partially pigmented; calcar’s length approximately 0.3 times that of fore femur; fore wing length 1.75 mm | Siccibythus pallidus Rasnitsyn, Zhang, Müller & Zhang, 2020 |
– | Fore wing with 2-A not pigmented (except for very base); calcar’s length less than 0.2 times that of fore femur | 10 |
10 | Pronotum with dorsal surface distinctly elongate; propodeal horns short, barely protruding; female flagellum not widened ( |
Siccibythus oculatus Rasnitsyn, Zhang, Müller & Zhang, 2020 |
– | Pronotum with dorsal surface subquadrate; propodeal horns long, clearly protruding (Fig. |
Siccibythus aristovi sp. nov. |
We assign the two species described here to †Falsiformicidae because of the sexual dimorphism in the number of antennomeres (females 12/males 13); notauli and parapsides present; fore wing venation reduced; hind wing with no closed cells and first metasomal tergum node-like. The new specimens exhibit consistent features, indicating that they belong to the same genus. They are distinguished from †Falsiformica and †Neophenax in having the fore wing 1m-cu not entirely tubular and dorsal surface of pronotum elongate or, rarely, subquadrate (
At the same time, †Falsiformicidae differ from Chrysidoidea and are similar to non-chrysidoid aculeates in the sexual dimorphism in the number of antennomeres (12 in females and 13 in males) and the 7th metasomal tergum internal in repose (
Based on the above analysis, the taxonomic position of †Falsiformicidae cannot yet be determined with certainty, comparison of characteristics between †Falsiformicidae, Chrysidoidea, and non-chrysidoid aculeates are listed in Table
Comparison of characteristics between †Falsiformicidae, Chrysidoidea, and non-chrysidoid aculeates.
†Falsiformicidae | Chrysidoidea | non-chrysidoid aculeates |
---|---|---|
Metepisternal-propodeal boundary clearly distinguishable | - | + |
Simplified forewing venation | + | + |
Constricted metapostnotum | + | - |
Usual broad propodeum with areolate sculpture | + | - |
Broad propodeum with areolate sculpture | - | + |
Metapostnotum forms a relatively wide trough with cross-ridged sculpturing | - | + |
Sexual dimorphism in antennomere count | - | + |
We thank the editorial board of Journal of Hymenoptera Research, and in particular Dr. Michael Ohl and Dr. Brendon Boudinot. We thank two reviewers for their valuable comments on this manuscript. We thank to Ms Weiwei Wang and Ms Yongfei Wang for their assistance with the measurement data. T.P.G was supported by the National Natural Science Foundation of China (Nos 32470468, 32020103006). A.P.R. was partially supported by the Presidium of the Russian Academy of Sciences Program “Origin of the Biosphere and Evolution of Geobiological Systems.” E.E.P. was partially supported by the Scholars at Risk Ukraine (SARU) program, jointly funded by the Villum Foundation, the Carlsberg Foundation, and the Novo Nordisk Foundation.
The measurements of the specimen (mm)
Data type: xlsx
Measurements and standard deviation analysis of CNU-HYM-MA2016212 (mm)
Data type: xlsx