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Data to "Wonderfully weird: The head anatomy of the armadillo ant, Tatuidris tatusia (Formicidae: Agroecomyrmecinae)". The dataset contains the raw µCT scan data and three surface models that can be used to generate 3D-prints of the head capsule and the mandible. The single specimen used in this study for μ-CT scanning was collected in Costa Rica: Alajuela, 5 km east of Monteverde, 10° 17' 47.2" N, 84° 46' 16.8" W, 1230 m above sea level (a.s.l.), wet forest, ex sifted leaf litter, Winkler, collection code JTL8695-s, 18.V.2014, leg. J. Longino. After μ-CT scanning, the specimen was given the unique specimen identifier (USI) CASENT0790526 and is now stored at the research collection of the Biodiversity and Biocomplexity Unit at the Okinawa Institute of Science and Technology. The head of the sample for μ-CT scanning was removed with forceps and stained in an alcoholic iodine solution for three days before it was mounted in a pipette tip filled with 99.9% ethanol. The images were captured with a Zeiss Xradia 510 Versa 3D X-ray microscope (Oberkochen, Germany) operated with the Zeiss Scout-and-Scan Control System software (version 11.1.6411.17883) at the Okinawa Institute of Science and Technology Graduate University, Japan. The scanning parameters chosen consisted of a 40 kV (75 μA) / 3 W beam strength with 20 s exposure time under a 4 × magnification, which resulted in a pixel image size of 1.41 μm. The distance between the sample and source was set to 13 mm and the distance to the detector to 50 mm. 3D reconstructions of the resulting scan projection data were done with the Zeiss Scout-and-Scan Control System Reconstructor (version 11.1.6411.17883) and saved in DICOM file format. Surface objects of the head capsule and mandible were generated with Amira (version 6.0) and exported as .stl files. These surface files were printed with an objet350 3D printer (Stratasys, Rehovot, Israel), using the solid, white digital acrylonitrile butadiene styrene material. The models were used to investigate the potential mandibular movement of Tatuidris tatusia.

† Desyopone hereon sp. nov. Boudinot and Perrichot (Figures 1–5) ZooBank LSID: urn: lsid:zoobank.org:act: 9E345965-6AA1-42D8-A468-187BABBB38D2. Etymology. The specific epithet gratefully recognizes the Helmholtz-Zentrum Hereon, the research center which funds and operates the Imaging Beamline (P05) at DESY, thus making the present work possible. Holotype. Male (m), MAIG 6016 (Figures 1B, 2A,B, 3 and 4), deposited in the Museum of Amber Inclusions at University of Gda´nsk, Poland. Paratypes. 12 males (m). Synincluded with holotype in amber piece MAIG 6016 (Figures 1A,C,D, 2C,D and 5). Type locality. Exact locality unknown in the Bashilo river gorge near Weldiya, Semien Wollo Zone, Amhara Region, Ethiopia. Type horizon. A fine siltstone/mudstone of Early Miocene age (16–23 Ma). Material. Holotype and paratypes 1–4 are nearly complete, preserved without apparent distortion but with integument entirely covered by a white, opaque (bacterial?) coat for paratypes 1, 2, 4 (Figures 1A,C and 2A). Paratypes 5–12 mostly complete but variously preserved, more or less distorted by apparent dehydration (e.g., Figure 1D). Diagnosis. † Desyopone hereon is uniquely identifiable among all Ponerinae by the distinctly elongate petiolar peduncle and the enlarged, lobate mandibles. Description. Measurements: Holotype (paratypes) (taken from paratypes 1,2,4)—BL 3.11 (3.00–3.50), HW 0.57 (0.50–0.60), HWE 0.70 (0.66–0.70), SL 0.12 (0.10–0.12), EL 0.23, OLL 0.08 (0.08), OIL 0.16 (0.16), WL 1.25 (1.25), ML 0.52 (0.50–0.56), MW 0.49, FWL (2.75), PH 0.26 (0.30), PL ~0.40 (0.40), GL 1.20 (1.00–1.50), GW 0.62 (0.65–0.80), HWI 81 (76–86), SI 21 (20), OCI 50 (50), PI 154 (133). Head (Figures 2–4): Head capsule ovoid-elliptical in lateral view; in full-face view, posterior head margin broadly and evenly convex to compound eyes; oral region of head, i.e., the malar areas, clypeus, and mouthparts, narrower than distance between compound eyes; postgenal bridge short, about 2/5 the length of the head in full-face view as measured from the postocciput to the hypostoma; malar areas distinctly developed; clypeus medially bulging, laterally depressed. Compound eyes situated almost entirely in anterior half of head; eyes subspherical and relatively small, with their length being about 1/3 head length. Ocelli distant from compound eyes, with the lateral ocelli separated from the compound eyes by slightly more than one compound eye length. Antennal toruli located at about head midlength in full-face view, distinctly posterad the posterior clypeal margin. Antennal scapes short, just barely longer than wide, with their length distinctly Mesosoma (Figures 2 and 3): Pronotum short and simple but with distinct muscular convexity as seen in lateral and dorsal views; posterad the anteromedian pronotal lobe (“nuchal lobe”), pronotum in the form of a simple arch, without distinct dorsal and ventral surfaces. Propleurae widely emarginate posteromedially, together forming a broad arch for the prosternum. Prosternum with basisternum apparently arcuate anteriorly; prosternal process developed. Mesoscutum somewhat narrow, with the anteroposterior length slightly greater than the lateromedial width. Notauli developed, and Y-shaped; meeting in the posterior half of the mesoscutum. Parapsides developed, although indistinct. Scutoscutellar sulcus broad, with at least five cross-costae. Mesoscutellum simple, convex, longer than broad in full-face view. Oblique mesopleural sulcus developed. Spiracular lobe (ventrad wing insertions) absent. Mesopleural area divided into dorsal and ventral regions; both regions dorsoventrally taller than anteroposteriorly long. Mesosternal and metasternal regions without processes. Propodeum convex, without armature or distinct sculpturation. Propodeal lobes developed, weak. Legs: Mesotibiae with no spur, metatibiae with a single, pectinate spur. Pretarsal claws narrow and simple, without additional teeth. Arolia well-developed but not very large. Fore wings (Figures 2C,D and 5): Costal vein (C) present, complete. Rsf1 diverging from Sc+ R +Rs well proximad pterostigma, with Sc+ R abscissa about 1/3 pterostigma length. Pterostigma well-developed, long, and narrow, with its length> 5 × its width. Rf distad pterostigma tubular. M+Cu tubular. Mf1 diverging from M+Cu at or slightly distad crossvein cu-a; this abscissa very weakly curved and meeting Rf1 at a distinct oblique angle. Rs+M tubular. Rsf2–3 diverging from Rs+M proximad 1m-cu. Crossvein 1r-rs absent. Crossvein 2r-rs anterior juncture at 2/3 length of pterostigma; this crossvein meeting Rsf proximad crossvein 2rs-m, which is tubular (paratype 4 has 2rs-m duplicated on the right wing, see Figure 2D). Rsf4+ tubular, meeting Rf distally). Mf2 (=abscissa between Rs+M and 1m-cu) short, shorter than 2r-rs and 2rs-m. Mf3 similar in length to but distinctly shorter than Rsf2–3. Mf4+ tubular proximally, becoming nebulous distally, with this occurring at a distance that is about 3 × the length of 2rs-m. Cuf3 (=abscissa of Cu after 1m-cu) joined to 1A posteriorly; 1A is tubular for its entire length. Submarginal cells 1 and 2 similar in size and shape, but with 2 distinctly smaller than 1. Marginal cell 1 long and narrow, with a length that is about 1.5 × pterostigma length. Discal cell 1 subrhomboidal, its length slightly less than 2 × its anteroposterior width. Subdiscal cell closed. Hind wings (Figures 2C and 5): Wing with eight distal hamuli. Jugal lobe absent. C not distinctly developed. R splitting from Sc+ R +Rs distad crossvein 1rs-m; Rf incomplete, not reaching anterior wing margin. Rsf tubular for a distance that is about 2 × the length of Sc+ R +Rs distad 1rs-m. M+Cu splitting well distad crossvein cu-a. Mf1 meeting rs-m at a broad, oblique angle; Mf developed as a stud distad this juncture. Cuf developed distad the split of M+Cu, but exact condition uncertain. Crossvein cu-a long, slightly longer than the length of Mf1; this crossvein situated proximad split of M+Cu by about twice its length. Anal vein (A) tubular past its juncture with cu-a. Anal cell relatively long; M+Cu proximad cu-a distinctly longer than M+Cu distad cu-a. Metasoma (Figures 2B and 3A,D,E): Petiole nodiform and distinctly pedunculate, albeit without a marked inflection between its anterior portion and the anterior surface of the petiolar node; peduncle about 2/5 petiole length; petiolar node height about 3/5 entire petiole length; node broad and convex; posterior collar well-developed; tergosternal fusion absent, laterotergites present; sternum low and very weakly sinuate in lateral view, without an anteroventral (=subpetiolar) process, nor with a posterior process; posterior sternal margin distinctly notched. Helcium infraaxial (=below abdominal segment III midheight); helcial tergite broad and overlapping sternite laterally. Prora not distinctly developed. Gastral segments homonomous in appearance and gradually decreasing in length from abdominal segment III to VIII. Abdominal segment IV without cinctus (=constriction). Abdominal spiracles IV–VIII obscured by preceding tergites. Abdominal tergum VIII apparently simple. Abdominal sternum IX lobate and somewhat narrow, with a length that is about twice its width. Cerci (=pygostyles) developed. Genitalia (Figures 2B and 3A): Cupula present (only visible in µ- CT cross-sections). Gonopods longer than tall. Gonostyli broad proximally, indistinctly set off from gonocoxa, and lobate in appearance, being narrowly rounded apically. Lateropenites (=digiti) thickened apically, downcurved. Penites (=penisvalvae) apparently longer than tall, curving strongly to their narrowly lobate apices. Setation: Body with two primary hair classes: (1) short pubescence, which covers the head and all segments of the antennae, mesosoma, legs, and metasoma; (2) long hairs, which are sparse on all body regions, but are denser on the metasoma., Published as part of Boudinot, Brendon E., Richter, Adrian K., Hammel, Jörg U., Szwedo, Jacek, Bojarski, Błażej & Perrichot, Vincent, 2022, Genomic-Phenomic Reciprocal Illumination: Desyopone hereon gen. et sp. nov., an Exceptional Aneuretine-like Fossil Ant from Ethiopian Amber (Hymenoptera: Formicidae: Ponerinae), pp. 1-19 in Insects 73 (796) on pages 9-13, DOI: 10.3390/insects13090796, http://zenodo.org/record/7046409

Tribe Ponerini Lepeletier de Saint-Fargeau, 1835. Type genus. Ponera Latreille, 1804. Male diagnosis. In addition to the ponerine plesiomorphies, male Ponerini are distinguished by the following: (1) mandibles vestigial, with an enlarged mandalus, and being variably lobate, spatulate, spiniform, or nub-like (no exceptions known) [synapomorphy, homoplastic among Formicidae]; (2) face between antennal toruli not distinctly raised, thus toruli directed more-or-less dorsally; if the intertorular region is raised, then this region is grooved in appearance due to impression of the supraclypeal area (=frontal triangle) (Plectroctena and Psalidomyrmex with medial torular arches raised, but not face; Hagensia, Megaponera, Ophthalmopone, Simopelta, some Euponera, and some Odontomachus with intertorular region raised) [plesiomorphy]; (3) antennal toruli usually distant from posterior clypeal margin (some Brachyponera, many Leptogenys, Megaponera, and Ophthalmopone have toruli that are close to the clypeal margin) [plesiomorphy]; (4) meso- and metatibiae with two, one, or no spurs; (5) jugal lobe present or absent; (6) helcium distinctly infraaxial, i.e., situated well below the midheight of abdominal segment III (Simopelta is an exception due to softening and reduction in size of the metasoma) [synapomorphy, homoplastic among Formicidae]; (7) abdominal segment IV with or without cinctus; (8) cuticle usually not pruinose, being shiny and variably sculptured (Belonopelta, Hagensia, Megaponera, and Ophthalmopone are exceptions) [plesiomorphy]. Remarks. Definitive infraaxiality in males, i.e., with abdominal tergum III rising high above the petiole, is a strong diagnostic condition for Ponerinae, as this is an infrequent apomorphic condition at the subfamily level. It also occurs in Dolichoderinae and Formicinae, and to some extent in Myrmeciinae and various Myrmicinae. Discothyrea (Proceratiinae) may approach infraaxiality, but the third abdominal tergum is low., Published as part of Boudinot, Brendon E., Richter, Adrian K., Hammel, Jörg U., Szwedo, Jacek, Bojarski, Błażej & Perrichot, Vincent, 2022, Genomic-Phenomic Reciprocal Illumination: Desyopone hereon gen. et sp. nov., an Exceptional Aneuretine-like Fossil Ant from Ethiopian Amber (Hymenoptera: Formicidae: Ponerinae), pp. 1-19 in Insects 73 (796) on page 8, DOI: 10.3390/insects13090796, http://zenodo.org/record/7046409

Genus † Desyopone gen. nov. Boudinot and Perrichot Type species. † Desyopone hereon sp. nov., by present designation monotypy. ZooBank LSID: urn:lsid:zoobank.org:act: 7228E671-DF5E-44D1-ADE6-62FB6DB34220. Etymology. The genus name is a portmanteau of the traditional ponerine generic suffix, “-pone”, and the acronym for the Deutsches Elektronen-Synchrotron (DESY), whose storage ring and radiation beamline facilities were used to generate the phenomic data that were crucial for the correct identification of the new taxon. Diagnosis. † Desyopone has plesiomorphies 1–4 of Ponerinae and is identifiable as Ponerini at minimum due to the vestigial mandibles and infraaxial helcium. † Desyopone and Cryptopone are uniquely identified among all Ponerinae by: (1) subpetiolar process completely absent, with the poststernite low and nearly flat in profile. The new genus differs from the males of all known Cryptopone by the following: (2) head broader than long, excluding the compound eyes (vs. head narrower than long); (3) mandibles elongate (vs. short); (4) mandibles lobate (vs. spiniform); (5) mesospiracular sclerite evidently absent (vs. this sclerite present); (6) meso- and metatibiae with no spur and one spur, respectively (vs. two spurs each); and (7) petiolar peduncle long, about as long as node is tall (vs. peduncle short, considerable shorter than height of node). Remarks. The identity of Cryptopone is significantly clarified by the phenomic data from the new species and the phylogenomic revision of Branstetter and Longino [50]. Prior to this work, the diagnostic importance of the absent subpetiolar process was obscured by the inclusion of Wadeura guianensis in Cryptopone. Now it is clear that the absence of the subpetiolar process is a unique condition among extant Ponerinae that is shared between † Desyopone gen. nov. and Cryptopone, and thus constitutes a reasonable autapomorphy within the subfamily for the two genera. No known Cryptopone, however, matches the diagnostic character combination of † Desyopone gen. nov., with conditions 3–7 being apomorphic. Critically, the elongate peduncle of † D. hereon gen. et sp. nov. is nearly unique among Ponerinae; this condition is similarly derived in Harpegnathos and is approached by Dinoponera, some Odontomachus (e.g., O. chelifer, O. coquereli), and Platythyrea (although node at middle of segment rather than posterior)., Published as part of Boudinot, Brendon E., Richter, Adrian K., Hammel, Jörg U., Szwedo, Jacek, Bojarski, Błażej & Perrichot, Vincent, 2022, Genomic-Phenomic Reciprocal Illumination: Desyopone hereon gen. et sp. nov., an Exceptional Aneuretine-like Fossil Ant from Ethiopian Amber (Hymenoptera: Formicidae: Ponerinae), pp. 1-19 in Insects 73 (796) on page 8, DOI: 10.3390/insects13090796, http://zenodo.org/record/7046409, {"references":["50. Branstetter, M. G.; Longino, J. T. UCE phylogenomics of New World Cryptopone (Hymenoptera: Formicidae) elucidates genus boundaries, species boundaries, and the vicariant history of a temperate - tropical disjunction. Insect Syst. Divers. 2022, 6, 1 - 23. [CrossRef]"]}

Subfamily Aneuretinae Emery, 1913. Type genus. Aneuretus Emery, 1893. Diagnosis (all adult castes). All adults of Aneuretinae possess the following diagnostic plesiomorphies (1–6): (1) mandibles shovel-shaped (=“triangular”) [plesiomorphy of Poneroformicia, or at least Doryloformicia]; (2) meso- and metatibiae with one spur each [synapomorphy of clade Dolichoderomorpha]; (3) petiole with complete tergosternal fusion [synapomorphy of clade Dolichoderomorpha]; (4) petiole with an elongate anterior peduncle [possible synapomorphy of clade Myrmechoderines]; (5) helcium infraaxial [possible synapomorphy of clade Myrmechoderines]; and (6) abdominal segment IV unconstricted [synapomorphy of clade Dolichoderomorpha]. Males and queens of Aneuretinae share the following diagnostic traits (7–12): (7) near-complete fore wing venation, with only the subdiscal cell open; (8) crossvein 2rs-m furcal to post-furcal, i.e., 2r-sm meeting Rs at or distad 2r-rs; (9) well-prefurcal fore wing crossvein cu-a, i.e., cu-a meeting M+Cu proximad the split of M+Cu by more than one of its own lengths; (10) absence of free M in the hind wing after the juncture of rs-m and Mf1, i.e., the abscissa between Sc+ R +Rs and M+Cu linear, without a kink; (11) hind wing anal cell short, its length less than half that of the basal cell; and (12) absence of the hind wing jugal lobe. Males of Aneuretinae have the following diagnostic plesiomorphy (13): (13) genital gonocoxa and gonostylus not strongly differentiated in size, with the dorsal gonocoxal margin continuing more-or-less evenly to that of the gonostylus. Workers and queens of Aneuretinae share the following diagnostic plesiomorphies (14, 15): (14) mandible with biseriate dentition, i.e., with small teeth interspersed between large teeth [synapomorphy of Dolichoderomorpha]; (15) basal and masticatory margins of mandible not marked, i.e., these margins curving into one another, without a distinct angle [synapomorphy of Dolichoderomorpha]. Remarks. The operational paleontological definition of Aneuretinae has relied on character states 2, 4, 6, 7 (regardless of subdiscal cell state), and 12. With the explicit recognition of character state 3—which was previously indicated for the “formicomorph subfamilies” by Bolton [11] (p. 16)—it is possible to reject the placement of † Desyopone hereon gen. et sp. nov. from the Aneuretinae. The condition of helcial axiality is here reinterpreted from Bolton [11] (p. 18), who described the helcium of Aneuretinae as “high on [the] anterior face of abdominal segment III”, which is interpretable as supraaxial sensu Keller [46]. Although the helcial tergite of worker Aneuretus is dorsoventrally short, it can be seen that the helcium is at the ventralmost position of the sternum, which does not broaden. An axial helcium is confirmed for the Baltic amber taxa † Paraneuretus and † Protaneuretus as well. Wing venation was observable for Aneuretus and † Paraneuretus. Finally, we recognize the mandibular character states 14 and 15 as critical for the identification of Aneuretinae. The states of the mandibles have not been previously remarked upon, but along with the conformation of the clypeus (not defined here), they form the gestalt of the Aneuretinae and Dolichoderinae, which was likely used by Wheeler [7] to place † Paraneuretus and † Protaneuretus, although his justifications were not made explicit. Further refinement of the aneuretine diagnosis via comparative phenomics and traditional comparative morphology is highly desirable., Published as part of Boudinot, Brendon E., Richter, Adrian K., Hammel, Jörg U., Szwedo, Jacek, Bojarski, Błażej & Perrichot, Vincent, 2022, Genomic-Phenomic Reciprocal Illumination: Desyopone hereon gen. et sp. nov., an Exceptional Aneuretine-like Fossil Ant from Ethiopian Amber (Hymenoptera: Formicidae: Ponerinae), pp. 1-19 in Insects 73 (796) on pages 6-7, DOI: 10.3390/insects13090796, http://zenodo.org/record/7046409, {"references":["11. Bolton, B. Synopsis and classification of Formicidae. Mem. Amer. Entomol. Inst. 2003, 71, 1 - 370.","46. Keller, R. A. A phylogenetic analysis of ant morphology (Hymenoptera: Formicidae) with special reference to the poneromorph subfamilies. Bull. Am. Mus. Nat. Hist. 2011, 355, 1 - 90. [CrossRef]","7. Wheeler, W. M. The ants of the Baltic Amber. Schrift. Physikal. Okonom. Gesell. Konigsberg 1915, 55, 1 - 142."]}

Tribe Platythyreini Emery, 1901. Type genus. Platythyrea Roger, 1863. Male diagnosis. In addition to the ponerine plesiomorphies, male Platythyreini are distinguished by the following: (1) mandibles worker-like, shovel-shaped (=“triangular”) [plesiomorphy]; (2) face between antennal toruli distinctly raised, such that the antennal toruli are directed relatively laterad, and are situated dorsad a depression which may receive the antenna [synapomorphy, homoplastic in Ponerini]; (3) antennal toruli usually close to or indenting the posterior margin of clypeus, toruli never distant from the posterior margin by more than half of one of their diameters [apomorphy]; (4) meso- and metatibiae with two spurs each [plesiomorphy]; (5) jugal lobe present [plesiomorphy]; (6) helcium not distinctly infraaxial, being axial to more-or-less axial, i.e., at about or just slightly below the midheight of abdominal segment III [plesiomorphy]; (7) abdominal segment IV with cinctus [plesiomorphy]; (8) cuticle pruinose [synapomorphy, homoplastic in Ponerini and some Proceratiinae]. Remarks. Because male Platythyreini have never been explicitly diagnosed, we found it necessary to provide a diagnosis in order to confirm the identification of the fossils in question. We observe that the mandibular form, tibial spur count, and cuticular sculpture of male Platythyreini are sufficient for identification at the global scale., Published as part of Boudinot, Brendon E., Richter, Adrian K., Hammel, Jörg U., Szwedo, Jacek, Bojarski, Błażej & Perrichot, Vincent, 2022, Genomic-Phenomic Reciprocal Illumination: Desyopone hereon gen. et sp. nov., an Exceptional Aneuretine-like Fossil Ant from Ethiopian Amber (Hymenoptera: Formicidae: Ponerinae), pp. 1-19 in Insects 73 (796) on pages 7-8, DOI: 10.3390/insects13090796, http://zenodo.org/record/7046409

TECHNOMYRMEX SVOJTKAI PERRICHOT & ENGEL SP. NOV. (FIGS 1–3; SUPPORTING INFORMATION, FIGS S1, S 2) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: 565B4980-A80E-450B-A09B-603264A91F50. Type material: Holotype NHMW-N6976, a complete worker; in Early Miocene (16–23 Mya) amber from the North Shewa Zone, Amhara region, Ethiopia; housed in the Department of Mineralogy and Petrography, Naturhistorisches Museum Wien (NHMW, Austria). Paratypes MAIG 6020, two workers missing portions of legs; in Early Miocene (16–23 Mya) amber from the South Wollo Zone, Amhara region, Ethiopia; housed in the Museum of Amber Inclusions of the University of Gdansk (MAIG, Poland). Other material: MAIG 6020, one worker missing the head, portions of legs and gaster, but similar to the associated paratypes in its size and preserved structures, particularly the subcylindrical petiole, the shape and position of metathoracic and propodeal spiracles, thus considered here as conspecific; housed in the Museum of Amber Inclusions of the University of Gdansk (MAIG, Poland). Etymology: The specific epithet honours Mr Matthias Svojtka (University of Vienna) who discovered the fossil representing the holotype and generously made it available for study. Diagnosis: The species is uniquely identified within Technomyrmex by the following combination of worker characters: (1) anterior clypeal margin with a deep V-shaped median incision; (2) inner margins of incision continuously arched, with no marked angle with broadly semicircular anterolateral clypeal margins; (3) dorsum of head with a single pair of stiff setae situated above posterior level of eyes; (4) compound eyes situated around midlength of head (EPI 59), with about 40 ommatidia; (5) palp formula 6,4; (6) mandible with six conspicuous teeth apically on masticatory margin; (7) counting from the apex, first tooth longest, third and fifth teeth subequal in length, smaller than second and fourth, third to sixth teeth each separated by one denticle, sixth tooth followed by a continuous series of smaller teeth gradually decreasing in size along masticatory margin and basal angle, becoming denticles along entire basal margin; (8) the basal angle indistinct, continuously arched between margins; (9) mesosoma devoid of erect setae; (10) propodeal dorsum as long as declivitous face, their junction broadly rounded. Description: Holotype. Body integument minutely asperous, mostly glabrous except sparse stiff setae on anterior head margin and gaster. Head only slightly longer than wide. Compound eye oval, moderately large and feebly convex, its outer margin barely surpassing the outline of sides in full-face view, with 38–40 ommatidia. Ocelli absent. Frontal carinae well distant, closer to inner margin of eyes than to each other, not surpassing posterior margin of eyes and without frontal lobe, such that antennal sockets entirely exposed although directed laterad. Antenna 12-merous, scape surpassing vertexal margin by more than one-third its length; first and terminal funicular antennomeres subequal in length, nearly twice as long as broad; all other antennomeres cylindrical, only slightly longer than broad. Vertex with an erect seta (likely paired, but upper left side of head altered) longitudinally aligned with frontal carina, in profile situated at midlength between posterior margins of eye and head. Anterior clypeal margin bordered by seven stiff, short setae inclined ventrally; posterior clypeal margin semicircular, even with posterior level of toruli. Mesosoma: in profile, mesonotal dorsal outline feebly convex in its anterior third, flat and sloped in its posterior two thirds. Mesonotum and propodeum forming a distinct angle at metanotal groove. Metathoracic spiracles raised into distinct tubercules, conspicuously breaking outline of mesosoma in lateral view, distinctly anterior to metanotal groove. Dorsal surface of propodeum flat, declivitous surface convex. In profile, propodeal spiracle at junction of lateral and declivitous surfaces, slightly above midheight of sclerite. Dorsal surface of mesosoma apparently without erect setae. Legs: mesotibia and metatibia each with one spur, that of metatibia pectinate. Metasoma: petiole more than twice as long as wide, nearly as wide as high, broadest around its midlength; ventral and dorsal surfaces feebly convex; ventral surface without lobe, with two anterior longitudinal rows of three short setae. Gaster: abdominal tergite III largest, ventral surface of its anterior projection with a groove that accommodates entire petiole. Tergites III–VI with posterior margin bordered by a row of short appressed setae barely surpassing margin. Tergite VII in dorsal view small, trapezoidal. Paratypes and other specimens: As for the holotype, although incomplete or partially concealed due to preservation, but with posterior margin of head intact, not emarginate (MAIG 6020 paratypes); palpomeres clearly exposed (MAIG 6020 paratype 1), revealing a palp formula 6,4, with maxillary palp relatively long, exceeding hypostomal margin but not reaching occiput, and labial palp short, about one-third length of maxillary palp; mesonotum constricted and elongate (MAIG 6020 additional worker). Measurements and indices: Abbreviations are explained in Material and methods. Holotype: BL ~ 2.00, HL 0.50, HW 0.49, EL 0.15, FcW 0.18, SL 0.59, WL 0.77, PL 0.30, PW 0.13, PH 0.12, GL 0.80, GW 0.55, CI 98, OI 30, EPI 59, SI 129. Paratypes and additional worker: HL 0.52–0.54, HW 0.46, EL 0.11–0.15, SL 0.52, WL 0.77, PL 0.25–0.35, PW 0.20, SI 110. Note: Amber piece MAIG 6020 also contains a fourth, partially preserved worker, which displays a similar petiole and can probably be attributed to Technomyrmex. However, only the mesosoma and petiole are preserved, and it differs by a larger size (WL ~ 2.40 vs. 0.77; PL 0.77 vs. 0.25–0.35) and the presence of a dense, short pubescence covering all sclerites; it probably belongs to another species. Among the dolichoderines, the petiole reduced to a low segment without a node or scale and overhung by the first gastral segment, which is anteriorly grooved, is shared by Technomyrmex and Tapinoma Förster, 1850. The pygidium exposed in dorsal view, thus with five gastral tergites visible, as is seen on the new fossil, warrants placement in Technomyrmex (whereas the pygidium is reflexed ventrally, exposing only four gastral tergites in dorsal view in Tapinoma; see, e.g. Bolton, 2007; Fisher & Bolton, 2016). The new species is readily recognizable by its anterior clypeal margin with a deep V-shaped incision and broadly rounded lateral margins, the almost complete lack of erect setae on the dorsum of head, mesosoma and first gastral tergite (with the exception of a single pair of setae posterior to the frontal carinae), and the propodeal dorsum that is as long as, or even slightly longer than, the declivitous surface. In all other species of Technomyrmex with a deeply incised clypeal margin, the median notch is either U-shaped or semicircular, but never V-shaped. These and other features, such as the elongate mesosoma and metathoracic spiracles raised on tubercles, suggest that Technomyrmex svojtkai may belong to the bicolor group of species as defined by Bolton (2007)., Published as part of Perrichot, Vincent, Boudinot, Brendon E., Engel, Michael S., Fls, Xu, Chunpeng, Bojarski, Błażej & Szwedo, Jacek, 2022, Ants (Hymenoptera: Formicidae) from Miocene Ethiopian amber: filling gaps in the geological record of African terrestrial biota, pp. 775-791 in Zoological Journal of the Linnean Society 196 on pages 780-782, DOI: 10.1093/zoolinnean/zlac053, http://zenodo.org/record/7195057, {"references":["Bolton B. 2007. Taxonomy of the dolichoderine ant genus Technomyrmex Mayr (Hymenoptera: Formicidae) based on the worker cast. Contributions of the American Entomological Institute 35: 1 - 150.","Fisher BL, Bolton B. 2016. Ants of Africa and Madagascar: a guide to the genera. Berkeley: University of California Press."]}

RAVAVY MIAFINA FISHER, 2009 Measurements and indices: (N = 4, taken from CASENT 0078664, CASENT 0080308, CASENT0115570, CASENT0474633.) BL c. 3.33–4.46, HL 2.37–2.45, HW 1.84–1.91, HWE 2.13–2.25, EL 0.34–0.43, MSL 0.08–0.09, FcW 0.49–0.55, SL 0.074– 0.98, OLL 0.24–0.28, OIL 0.44–0.56, WL 1.30–1.67, ML 0.68–0.78, MW 0.81–0.92, FWL 3.85–4.24, PL 0.15–0.19, PW –, PH 0.28–0.31, GL 1.64–2.29, GW 0.58–0.70, CI 88–92, HWI 112–114 (122), MSI 28–32, SI 39–53, OI 14–18, EPI –, OCI 44–62, MI 104–129, PI 51–67., Published as part of Perrichot, Vincent, Boudinot, Brendon E., Engel, Michael S., Fls, Xu, Chunpeng, Bojarski, Błażej & Szwedo, Jacek, 2022, Ants (Hymenoptera: Formicidae) from Miocene Ethiopian amber: filling gaps in the geological record of African terrestrial biota, pp. 775-791 in Zoological Journal of the Linnean Society 196 on page 785, DOI: 10.1093/zoolinnean/zlac053, http://zenodo.org/record/7195057, {"references":["Fisher BL. 2009. Two new dolichoderine ant genera from Madagascar: Aptinoma gen. n. and Ravavy gen. n. (Hymenoptera: Formicidae). Zootaxa 2118: 37 - 52."]}

GENUS RAVAVY FISHER, 2009 Type species: Ravavy miafina Fisher, 2009: 47, figs 6, 7b., Published as part of Perrichot, Vincent, Boudinot, Brendon E., Engel, Michael S., Fls, Xu, Chunpeng, Bojarski, Błażej & Szwedo, Jacek, 2022, Ants (Hymenoptera: Formicidae) from Miocene Ethiopian amber: filling gaps in the geological record of African terrestrial biota, pp. 775-791 in Zoological Journal of the Linnean Society 196 on page 782, DOI: 10.1093/zoolinnean/zlac053, http://zenodo.org/record/7195057, {"references":["Fisher BL. 2009. Two new dolichoderine ant genera from Madagascar: Aptinoma gen. n. and Ravavy gen. n. (Hymenoptera: Formicidae). Zootaxa 2118: 37 - 52."]}

GENUS TECHNOMYRMEX MAYR, 1872 Type species: Technomyrmex strenuus Mayr, 1872: 147., Published as part of Perrichot, Vincent, Boudinot, Brendon E., Engel, Michael S., Fls, Xu, Chunpeng, Bojarski, Błażej & Szwedo, Jacek, 2022, Ants (Hymenoptera: Formicidae) from Miocene Ethiopian amber: filling gaps in the geological record of African terrestrial biota, pp. 775-791 in Zoological Journal of the Linnean Society 196 on page 780, DOI: 10.1093/zoolinnean/zlac053, http://zenodo.org/record/7195057, {"references":["Mayr G. 1872. Formicidae Borneensis collectae a J. Doria et O. Beccari in territorio Sarawak annis 1865 - 1867. Annali del Museo Civico di Storia Naturale 2: 133 - 155."]}

RAVAVY GOLDMANI BOUDINOT & PERRICHOT SP. NOV. (FIGS 4–5) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: 693FB2F0-817E-4BD6-B2E4-5585AFC99EA2. Type material: Holotype NIGP180512, male, housed in the Nanjing Institute of Geology and Palaeontology (NIGPAS, China); paratype IGR.ET2015/001a, male, housed in the Geological Museum of the University of Rennes (IGR, France). In Early Miocene (16–23 Mya) amber from the North Shewa Zone, Amhara region, Ethiopia. Etymology: The specific epithet honours Mr Yale Goldman (Bloomfield, Connecticut) who kindly facilitated access to the type specimens of the new species. Diagnosis: Because of the limited knowledge of male ants at the global scale, this diagnosis is broken into four parts in order to establish the identity of the treated specimens: identification at the subfamilial, tribal, generic and species levels. (I) Identifiable as Dolichoderinae by the following combination: (1) clypeal condyle large, rhomboidal (see note 1 below); (2) forewing cross-vein cu-a prefurcal, i.e. joining M+Cu proximad branching point of M and Cu; (3) helcium infraaxial; (4) abdominal segment III unpetiolated, i.e. not reduced in size relative to segment IV; (5) prora absent; (6) abdominal segment IV without cinctus; (7) gonostylus dorsoventrally short relative to gonocoxite, proximally constricted and not extending proximad gonocoxite (note 2); (8) basivolsellar process present (note 3). (II) Identifiable as Bothriomyrmecini by the following combination (note 4): (9) clypeus not extending posteriorly between toruli; (10) medial hypostomal lamina absent; (11) forewing cross-vein 2rs-m absent. (III) Identifiable as Ravavy by the following features, all of which are unique within Bothriomyrmecini (note 5): (12) mandible unidentate, spatulate with an apical spiniform tooth (vs. mandible multidentate, strapshaped to spiniform) (note 6); (13) palp formula 6,3 (vs. 6,4 or ≤ 4,3) (note 7); (14) pterostigma situated immediately proximad forewing midlength (vs. situated distad); (15) marginal cell extremely long, somewhat more than twice the length of submarginal cell 1; (16) Rf appendix, i.e. distalmost free abscissa of R, long, somewhat shorter than pterostigma; (17) discal cell subrectangular, longer proximodistally than wide anteroposteriorly and size small; (18) petiolar node broadly convex in profile view (vs. anteroposteriorly narrow and squamiform); (19) penite apices not downcurved, but rather being produced distally as long, linear processes. (IV) Distinguished from Ravavy miafina by the following (note 8): (20) smaller, BL ~ 2.57–2.34, WL ~ 0.43–0.46, FWL ~ 2.17–2.52 (vs. larger, BL ~3.33–4.46, WL ~ 1.30–1.67, FWL ~ 3.85–3.99); (21) head somewhat broader, CI ~ 122 (vs. narrower, CI ~112–114, although 122 in one specimen); (22) malar space relatively long, MSI ~ 6 and space distinctly longer than proximal width of mandible in lateral view (vs. relatively short, MSI ~ 28–32 and distinctly shorter than proximal mandibular width); (23) eye relatively long, OI ~ 40–39 (vs. eye relatively short, OI ~ 14–18); (24) ocelli relatively small, OCI ~ 38 (vs. 44–62); (25) antennomere III but not IV slightly kinked (vs. both antennomeres kinked); (26) mesoscutum relatively long, MI ~ 80 (vs. short, MI ~ 104–131); (27) scutoscutellar sulcus distinctly broad (vs. short, almost line-like); (28) petiole relatively long, PI ~ 80 (vs. short, PI ~ 51–67); (29) bristle-like setae apparently not developed on gastral sternites (vs. such setae present on all gastral sternites except the first); (30) abdominal sternum IX posterior margin broadly convex (vs. broadly emarginate); (31) gonostyli relatively long, length ~ 2–3 × height (vs. short, length ~ 1 × height); (32) gonostylar apices narrowly pointed (vs. broadly rounded); (33) ventral margin of penite more-or-less linear from base to apex (vs. base produced ventrally as a dorsoventrally long, anteroposteriorly narrow, serrate lobe); and (34) apicoventral penite processes short, length from proximodorsal inflection point ~ 1 × height (vs. long, length ~ 4 × height). Notes on diagnosis: 1. A large, rhomboidal clypeal condyle is an apparent synapomorphy of the Dolichoderomorpha, i.e. Dolichoderinae + Aneuretinae. The clypeal condyle of Formicinae and other subfamilies is variable in shape, often anteroposteriorly narrow. 2. The form of the gonopod is an apparent synapomorphy of Dolichoderinae as it is not shared with Aneuretinae. 3. Most dolichoderines have a posteroventral (ventroapical) basivolsellar process, which may be short and triangular to elongate and digitate. The process is absent in Azteca Forel, 1878 and Gracilidris Wild & Cuezzo, 2006 (sister taxa), Ochetellus Shattuck, 1992 and some Dolichoderus Lund, 1831. Formicines do not have a basivolsellar process; such a process is present convergently in the Amblyoponinae, which is a synapomorphy for that subfamily (Yoshimura & Fisher, 2012; Boudinot, 2015). 4. In their recent phylogenetic revision of the Dolichoderinae, Ward et al. (2010) provided reduction or loss of the medial hypostomal lamina as a synapomorphy of the Bothriomyrmecini that occurs in both sexes. Subsequently, Boudinot et al. (2016) recognized loss of forewing cross-vein 2rs-m as another diagnostic condition. Here, we propose the ‘short’ condition of the clypeus as an additional synapomorphy of the tribe. The clypeus in both males and females extends posteriorly between the antennal toruli in the majority of dolichoderine genera with only a few exceptions (Shattuck, 1992; Boudinot, 2015), such as the neotropicus and macro clades of Leptomyrmex Mayr, 1862 (Lucky & Ward, 2010; Boudinot et al., 2016; Barden et al., 2017). 5. Males and queens of the Bornean genus Loweriella Shattuck, 1992 are unknown in contrast to the other three bothriomyrmecine genera (Bothriomyrmex Emery, 1869a, Chronoxenus Santschi, 1919, Ravavy). Because Loweriella is the sister-group of Ravavy (Ward et al., 2010), a number of the diagnostic traits of the latter genus adduced here may be synapomorphies of the two genera. 6. Yoshimura & Fisher (2011) tentatively remarked that additional, vestigial denticles may be present in R. miafina and label a possible denticle on a dissected mandible imaged with a compound microscope. Because this apparent denticle is on the lateral mandibular margin, and as the apical tooth is a consistent feature of even ‘edentate’ mandibles (Boudinot et al., 2021), we interpret the mandible of R. miafina as strictly unidentate. 7. The 6,3 palpomere count is an apparent synapomorphy of Ravavy within the Bothriomyrmecini. Loweriella has a plesiomorphic 6,4 count, while Bothriomyrmex and Chronoxenus share a derived, reduced count which is ≤ 4,3 (Bolton, 2003; Fisher, 2009; Yoshimura & Fisher, 2011). 8. The fine anatomy and morphology of R. miafina is illustrated in Fisher (2009) and especiallyYoshimura & Fisher (2011). The latter work provided a revised diagnosis of this species plus a comparative analysis of genitalic form. Comparisons were made to the images in the literature, on AntWeb (2022), and to specimens examined at the California Academy of Sciences. Description: Integument uniformly imbricate, apparently with a more-or-less even vestiture of extremely short and appressed pubescence; bristlelike setae not visible on body with exception of tarsi, gastral tergites and gonostyli, those of gastral tergites sparse. Head roughly rectangular, narrow anterad eyes and broader posteriorly; malar space relatively broad, being longer than proximal width of mandible in lateral view; posterior head margin emarginate. Compound eye bulging, length slightly less than half head-length, subreniform with subtle emargination occurring on along ventral eye margin and with> 175 ommatidia but probably not more than 200 (complete count not possible). Ocelli small; lateral ocelli relatively wideset, separated from one another by somewhat more than three lateral ocellar lengths. Frontal carinae poorly developed. Antenna 13-merous, scape about as long as compound eye and about 3 × as long as pedicel; pedicel about twice as long as wide and slightly more than half the length of antennomere III; antennomere III slightly kinked at about midlength; antennomeres III–XIII subequal in length and about 4 × as long as wide. Ocellar sensilla (setae) not visible. Anterior clypeal margin more-orless linear; clypeal setation not observable; posterior clypeal margin convex, portion of epistomal sulcus anterad and between toruli linear, weakly concave. Mandibles spiniform, tapering to their unidentate apices, thus appearing wedge-shaped in dorsal view. Labrum deeply notched apically, sides distinctly narrowing apicomediad. Palp formula 6,3; maxillary palp relatively long, exceeding hypostomal margin but not occiput; labial palp short, about one-fourth length of maxillary palp. Prementum elongate, diamond shaped. Stipes without transverse carina. Medial hypostomal lamina absent. Pronotum short, strap-like. Mesoscutum relatively long, with maximum length greater than maximum width; notauli absent; parapsides diverging anteriorly; scutoscutellar sulcus distinctly broad; lateral mesopectal sulcus sinuate. Upper metapleural region distinct, about 4 × as long as broad; lower metapleural region indistinct. Propodeum without distinct dorsal and posterior surfaces; propodeal spiracle small, circular, set slightly below metaphragmal pit. Femora puny, thin; metafemur and metatibia slightly sinuate. Tibial spur formula 1,1. Arolia small, barely visible. Petiole elliptical in lateral view, with broadly convex tergum and sternum; node not squamiform. Abdominal tergum III with broad but shallow concavity anteriorly above helcium. Abdominal segments III–VII similar in size, unmodified. Abdominal sterna VII–VIII broadly emarginate posteriorly. Abdominal sternum IX posterior margin convex, simple. Cerci not visible. Cupula not visible. Gonocoxite length uncertain; gonocoxital apex distinctly offset from gonostylar base. Gonostylus elongate, triangular; length about 2–3 × width; apex narrowly pointed. Volsellae incompletely visible; basivolsellar process present, acute; cuspis absent; lateropenite (= digitus) apex directed ventrad at nearly right angle relative to body of volsella; dorsal margin of digitus almost lobate; digital apices narrowing, almost rod-like and curved laterad. Ventral margins of penites moreor-less linear from base to apex; dorsal margins broadly convex in lateral view; apical processes directed posterad and relatively short, length from proximodorsal inflection point ~ 1 × height. Fore and hind wing venation virtually identical to R. miafina. Jugal lobe absent. Measurements and indices: Dashes indicate metric could not be taken or calculated. Holotype: BL ~ 2.34, HL 0.54, HW 0.41, HWE 0.50, EL 0.21, MSL 0.09, FcW –, SL –, OLL –, OIL –, WL 0.91, ML 0.43, MW –, FWL 2.17, PL –, PW 0.09, PH 0.12, GL 0.86, GW 0.43, CI 92, HWI 122, MSI 6, SI –, OI 39, EPI –, OCI –, MI –, PI –. Paratype: BL ~ 2.57, HL 0.54, HW 0.41, HWE 0.48, MSL 0.09, EL 0.22, FcW 0.12, SL 0.22, OLL 0.04, OIL 0.011, WL 0.98, ML 0.46, MW 0.37, FWL 2.52, PL 0.12, PW –, PH 0.15, GL 0.93, GW 0.54, CI 90, HWI –, MSI 6, SI –, OI 40, EPI –, OCI 38, MI 80, PI 80. Note: For comparison, see the metrics for R. miafina provided below., Published as part of Perrichot, Vincent, Boudinot, Brendon E., Engel, Michael S., Fls, Xu, Chunpeng, Bojarski, Błażej & Szwedo, Jacek, 2022, Ants (Hymenoptera: Formicidae) from Miocene Ethiopian amber: filling gaps in the geological record of African terrestrial biota, pp. 775-791 in Zoological Journal of the Linnean Society 196 on pages 782-785, DOI: 10.1093/zoolinnean/zlac053, http://zenodo.org/record/7195057, {"references":["Forel A. 1878. Etudes myrmecologiques en 1878 (premiere partie) avec l'anatomie du gesier des fourmis. Bulletin de la Societe Vaudoise des Sciences Naturelles 15: 337 - 392.","Wild AL, Cuezzo F. 2006. Rediscovery of a fossil dolichoderine ant lineage (Hymenoptera: Formicidae: Dolichoderinae) and a description of a new genus from South America. Zootaxa 1142: 57 - 68.","Shattuck SO. 1992. Generic revision of the ant subfamily Dolichoderinae (Hymenoptera: Formicidae). Sociobiology 21: 1 - 181.","Lund PW. 1831. Lettre sur les habitudes de quelques fourmis du Bresil, adressee a M. Audouin. Annales des Sciences Naturelles 23: 113 - 138.","Yoshimura M, Fisher BL. 2012. A revision of male ants of the Malagasy Amblyoponinae (Hymenoptera: Formicidae) with resurrections of the genera Stigmatomma and Xymmer. PLoS One 7: e 33325.","Boudinot BE. 2015. Contributions to the knowledge of Formicidae (Hymenoptera, Aculeata): a new diagnosis of the family, the first global male-based key to subfamilies, and a treatment of early branching lineages. European Journal of Taxonomy 120: 1 - 62.","Ward PS, Brady SG, Fisher BL, Schultz TR. 2010. Phylogeny and biogeography of dolichoderine ants: effects of data partitioning and relict taxa on historical inference. Systematic Biology 59: 342 - 362.","Boudinot BE, Probst RS, Brandao CRF, Feitosa RM, Ward PS. 2016. Out of the Neotropics: newly discovered relictual species sheds light on the biogeographical history of spider ants (Leptomyrmex, Dolichoderinae, Formicidae). Systematic Entomology 41: 658 - 671.","Mayr G. 1862. Myrmecologische Studien. Verhandlungen der Kaiserlich-Koniglichen Zoologisch-Botanischen Gesellschaft in Wien 12: 649 - 776.","Lucky A, Ward PS. 2010. Taxonomic revision of the ant genus Leptomyrmex Mayr (Hymenoptera: Formicidae). Zootaxa 2688: 1 - 67.","Barden P, Boudinot BE, Lucky A. 2017. Where fossils dare and males matter: combined morphological and molecular analysis untangles the evolutionary history of the spider ant genus Leptomyrmex Mayr (Hymenoptera: Dolichoderinae). Invertebrate Systematics 31: 765 - 780.","Emery C. 1869 a. Descrizione di una nuova formica italiana. Annuario del Museo Zoologico della Reale Universita de Napoli 5: 117 - 118.","Santschi F. 1919. Fourmis du genre Bothriomyrmex Emery (Systematique et moeurs). Revue Zoologique Africaine 7: 201 - 224.","Yoshimura M, Fisher BL. 2011. A revision of male ants of the Malagasy region (Hymenoptera: Formicidae): key to genera of the subfamily Dolichoderinae. Zootaxa 2794: 1 - 34.","Boudinot BE, Moosdorf OTD, Beutel RG, Richter A. 2021. Anatomy and evolution of the head of Dorylus helvolus (Formicidae: Dorylinae): patterns of sex- and caste-limited traits in the sausagefly and the driver ant. Journal of Morphology 282: 1616 - 1658.","Bolton B. 2003. Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute 71: 1 - 370.","Fisher BL. 2009. Two new dolichoderine ant genera from Madagascar: Aptinoma gen. n. and Ravavy gen. n. (Hymenoptera: Formicidae). Zootaxa 2118: 37 - 52."]}

Perrichot, Vincent, Boudinot, Brendon E., Engel, Michael S., Fls, Xu, Chunpeng, Bojarski, Błażej, Szwedo, Jacek (2022): Ants (Hymenoptera: Formicidae) from Miocene Ethiopian amber: filling gaps in the geological record of African terrestrial biota. Zoological Journal of the Linnean Society 196: 775-791, DOI: 10.1093/zoolinnean/zlac053

GENUS † GERONTOFORMICA NEL & PERRAULT, 2004 = † Sphecomyrmodes Engel & Grimaldi, 2005 junior syn.: Barden & Grimaldi (2016): 518. TAXONOMIC SYNOPSIS OF † GERONTOFORMICA I. Species group of cretacica (newly recognized) (Charentese amber) [Note 1]: 1. † G. cretacica Nel & Perrault, 2004 nomen dubium (new status) [Note 2] – Type species of † Gerontoformica Nel & Perrault, 2004 2. † G. occidentalis (Perrichot et al., 2008) II. Species group of gracilis (newly recognized) (Kachin amber): 3. † G. gracilis (Barden & Grimaldi, 2014) 4. † G. robusta (Barden & Grimaldi, 2014) 5. † G. spiralis (Barden & Grimaldi, 2014) [Note 3] 6. † G. subcuspis (Barden & Grimaldi, 2014) [Note 3] III. Species group of pilosa (Kachin amber): 7. † G. sternorhabda sp. nov. 8. † G. contega (Barden & Grimaldi, 2014) 9. † G. magna (Barden & Grimaldi, 2014) 10. † G. pilosa (Barden & Grimaldi, 2014) IV. Incertae sedis to species group within genus (Kachin amber): (11.) † G. orientalis (Engel & Grimaldi, 2005) nomen dubium (new status) [Note 4] – Type species of † Sphecomyrmodes Engel & Grimaldi, 2005 (12.) † G. rugosa (Barden & Grimaldi, 2014) nomen dubium (new status) [Note 5] (13.) † G. tendir (Barden & Grimaldi, 2014) nomen dubium (new status) [Notes 5, 6] Notes on classification Note 1: Under the label of ‘ orientalis group’, Boudinot et al. (2020b) previously united the cretacica and gracilis groups with the species † G. orientalis. The cretacica and gracilis groups are here divided based on the distinct forms of their petioles. The species † G. orientalis is of insufficient preservation for specieslevel identification (see Note 4 below). Note 2: The holotype of † Gerontoformica cretacica is poorly preserved, as noted by Barden & Grimaldi (2016), with obvious distortions and elongation of the scapes and flagella, and little detail of the body visible. Due to this unfortunate circumstance, we newly consider † G. cretacica to be a nomen dubium. It remains in the cretacica species group of † Gerontoformica, because it is the type species of the genus. However, it will be highly desirable to clarify the identity of this species through examination and description of more Charentese ants. At present, the only distinction between † G. cretacica and the co-eval † G. occidentalis that is not apparently affected by preservation is body size, with the former having a longer mesosoma than the latter (2.1 mm vs. 1.4 mm, respectively). Body size is, of course, highly variable among nestmates of crown ants, thus is a weak diagnostic trait when used in isolation and without the quantification of variation across conspecific individuals. Note 3: † Gerontoformica spiralis and † G. subcuspis were difficult to separate in the present study based on the available anatomical evidence and may be conspecific. Specifically, we observe that, in addition to conditions outlined in the key (see that section below), the two species are highly similar in the following conditions, which we only roughly characterize here: (1) proportions and fine details of the head, including frontal carina shape; (2) the degree of mesonotal, metanotal and propodeal convexity; (3) the width of separation between the meso- and metanota plus metanotum and propodeum; (4) the shape and proportions of the petiolar node; and (5) the form of the third abdominal (first ‘gastral’) segment. It is possible that † G. spiralis and † G. subcuspis represent the smaller and larger ranges of body size of a single species, with the former reported to have a total body length of 4.22–5.22 mm and the latter 5.35–5.76 mm (Barden & Grimaldi, 2014). Our focal uncertainties relate to the shapes and setational patterns of the tarsi of † G. subcuspis, and the form of the subpetiolar process and prora of † G. spiralis. A potential feature separating the two species is the distance of the toruli from the posterior clypeal margin, which appears to be narrower in † G. spiralis relative to † G. subcuspis, but this could be a visual artefact caused by the apparent light distortion in the holotype image of † G. spiralis. We recommend further re-evaluation of these two species, ideally using µ-CT and additional light photography to resolve the uncertainties of the tarsi, toruli and sternal processes of the metasoma. See also Note 1 on the diagnosis of † G. gracilis. Note 4: † Gerontoformica orientalis, the type species of † Sphecomyrmodes, is identifiable as † Gerontoformica relative to † Sphecomyrma Wilson & Brown, 1967 by the absence of the anteromedian clypeal process and presence of traction setae/ chaetae along the anterior clypeal margin, as recognized in the original description (Engel & Grimaldi, 2005) and illustrated in Boudinot et al. (2020b). However, in † Gerontoformica, the species † G. orientalis is unidentifiable due to poor preservation. No details of the head are clearly observable, except for the antenna, mandibles and anterior clypeal margin, while the mesosoma appears strongly distorted, the petiole is obscured, and the metasoma is mostly disarticulated. Boudinot et al. (2020b) placed † G. orientalis in the orientalis species group along with the type species of † Gerontoformica based on the absence of the cinctus of abdominal segment IV. As a more refined placement is not possible, we newly consider this species to be a nomen dubium. Note 5: † Gerontoformica rugosa and † G. tendir are newly considered as nomina dubia due to their poor preservation, being strongly desiccated and thus distorted. Both species appear to have some degree of abdominal segment III petiolation, as observed in the three confirmed members of the pilosa group, but it cannot be determined whether this is natural or exaggerated due to preservation. It is possible, but not yet determinable, that † G. rugosa is conspecific with † G. gracilis. That † G. rugosa or † G. tendir do have sculptured integument remains possible but requires substantiation via additional material of these species. We note that little surface texture variation has been explicitly documented among stem ants thus far. Note 6: † Gerontoformica tendir was defined by Barden & Grimaldi (2014) as having a medial clypeal lobe. This anteromedian lobe not only bears traction setae/chaetae, as previously observed, but is also lateromedially broader and proximodistally shorter than that of † Sphecomyrma. Given the poor preservation, it is possible that the apparent lobate form may be due to distortion of the amber matrix, as the lobe consists of the entire medial portion of the clypeus, which is distinct from the lateral clypeal lobes. Based on direct examination of the holotype, it appears that there is a transverse mesonotal carina in † G. tendir, but this also requires re-evaluation. Without additional specimens having an exaggerated and broadly, medially lobate clypeus, we remain uncertain about the identity of the species. A state of potential value for confirming the identity of † G. tendir from additional material is the absence of teeth on the pretarsal claws, as illustrated by Barden & Grimaldi (2014). Remarks The genus † Gerontoformica currently consists of 13 species, including the newly described † G. sternorhabda. The holotypes of nine of these species are sufficiently preserved for species-level identification, with eight of these being sufficiently defined given the potential synonymy of two (see Note 3 above). At the generic level, † Gerontoformica differs from † Sphecomyrma by presence of traction setae/chaetae along the anterior clypeal margin and absence of a narrow anteromedian clypeal lobe. These two conditions were used by Engel & Grimaldi (2005) to establish the genus † Sphecomyrmodes, which was synonymized under † Gerontoformica by Barden & Grimaldi (2016) after examination of the holotype of the type species of the latter taxon. Collectively, † Gerontoformica and † Sphecomyrmodes have been revised piecemeal after the former’s establishment by Nel et al. (2004). Specifically, Barden & Grimaldi (2014) added nine species of † Sphecomyrmodes, Barden & Grimaldi (2016) transferred all species of † Sphecomyrmodes to † Gerontoformica, and Boudinot et al. (2020b) moved one species to † Myanmyrma and recognized two morphologically defined groups of species in the genus. To understand the shifting boundaries of † Gerontoformica in the light of the present µ-CT-driven study, we detail the species-level history of the genus. Species attributed to the genus are distributed in Kachin amber (11 total) and Charentese amber (two total). The Charentese species, † G. cretacica and † G. occidentalis, were described four years apart by Nel et al. (2004) and Perrichot et al. (2008), respectively. Perrichot et al. described the smaller-bodied † G. occidentalis as † Sphecomyrmodes in comparison to the type species of that genus – † G. orientalis from Kachin amber – without comparison to † G. cretacica. Unfortunately, given the current status of morphological knowledge, the holotypes of both † G. orientalis and † G. cretacica are too poorly preserved to allow for confident specieslevel identification. However, both Charentese species uniquely share a distinct, nearly squamiform petiolar shape, with the node being anteroposteriorly narrow and dorsoventrally tall; this indicates that the Charentese species are closely related to one another, relative to the Kachin species. For this reason, we group † G. cretacica and † G. occidentalis together in the cretacica species group. It is possible that † G. cretacica and † G. occidentalis are conspecific, but any taxonomic action should wait for the accumulation and processing of more material from the Charentese formation. The identifiable Kachin species of † Gerontoformica, i.e. excluding † G. orientalis, † G. rugosa and † G. tendir, are evenly distributed in the G. gracilis and G. pilosa groups, with four species each. All species of the pilosa group are highly distinct in body form and setation, with † G. sternorhabda being an outlier, having the smallest body size and least pronounced constriction of the fourth abdominal segment, in addition to other defining features (see the species diagnosis below). In contrast, species of the newly recognized gracilis group are all largely similar to one another, without easily recognizable diagnostic structures. The most distinct Kachin species of the gracilis group is † G. robusta, which has a boxy mesosoma, with the meso- and metanota forming a nearly linear dorsal margin in lateral view. The other species of the gracilis group have a multi-humped profile due to the bulgelike development of the meso- and metanota and are otherwise similar to one another (see Note 1 on the diagnosis of † G. gracilis)., Published as part of Boudinot, Brendon E., Richter, Adrian, Katzke, Julian, Chaul, Júlio C. M., Keller, Roberto A., Economo, Evan P., Beutel, Rolf Georg & Yamamoto, Shûhei, 2022, Evidence for the evolution of eusociality in stem ants and a systematic revision of † Gerontoformica (Hymenoptera: Formicidae), pp. 1355-1389 in Zoological Journal of the Linnean Society 195 on pages 1361-1363, DOI: 10.1093/zoolinnean/zlab097, http://zenodo.org/record/6994456, {"references":["Nel A, Perrault G, Perrichot V, Neraudeau D. 2004. The oldest ant in the Lower Cretaceous amber of Charente- Maritime (SW France) (Insecta: Hymenoptera: Formicidae). Geologica Acta 2: 23 - 29.","Engel MS, Grimaldi DA. 2005. Primitive new ants in Cretaceous amber from Myanmar, New Jersey, and Canada (Hymenoptera: Formicidae). American Museum Novitates 3485: 1 - 23.","Barden P, Grimaldi D. 2016. Adaptive radiation in socially advanced stem-group ants from the Cretaceous. Current Biology 26: 1 - 7.","Perrichot V, Nel A, Neraudeau D, Lacau S, Guyot T. 2008. New fossil ants in French Cretaceous amber (Hymenoptera: Formicidae). Naturwissenschaften 95: 91 - 97.","Barden P, Grimaldi D. 2014. A diverse ant fauna from the mid-Cretaceous of Myanmar (Hymenoptera: Formicidae). PLoS One 9: e 93627.","Boudinot BE, Perrichot V, Chaul JCM. 2020 b. † Camelosphecia gen. nov., lost ant-wasp intermediates from the mid-Cretaceous (Hymenoptera, Formicoidea). ZooKeys 1005: 21 - 55."]}

† GERONTOFORMICA GRACILIS (BARDEN & GRIMALDI, 2014) (FIGS 1A, B, 2A, B, D, E, G, H, J, K, 8, 9, 10, 11 (1’-2), 12(7-1); SUPPORTING INFORMATION, FIG. S3) † Sphecomyrmodes gracilis Barden & Grimaldi, 2014: 4–7, figs 2, 10B, 11C, D (wingless female, Kachin amber, JZC-Bu324A, AMNH). Combination in † Gerontoformica: Barden & Grimaldi (2016): 518, suppl. info. p. 16. Diagnosis (wingless female) Similarly identifiable as † G. sternorhabda to the genus † Gerontoformica (I–III above), including absence of the anteromedian lobate clypeal process [Note 1]. For the diagnosis and redescription, see Figures 2, 8 and 10 primarily. I. Among † Gerontoformica, with the following unique character : (1) proximal labial palpomere with a distinct, apicomedially situated lobate process (Fig. 7A, B) [Note 2]; II. Within † Gerontoformica, identifiable as a member of the gracilis species group : (2) mesoscutum without distinct, raised transverse carina separating mesoscutal and mesoscutellar regions (Fig. 10A); (3) tergum of petiolar node anteroposteriorly longer than dorsoventrally tall (high); and (4) abdominal segment IV without cinctus dividing the tergum and sternum into pre- and postsclerites; III. Within the gracilis species group, identified by the following : (5) petiole bun-like, with anteroposteriorly long node; vs. subsquamiform, with anteroposteriorly narrow node († G. cretacica and † G. occidentalis); (6) meso- and metanota bulging, with their dorsal silhouette bihumped; vs. meso- and metanota not bulging, with their dorsal silhouette forming an almost straight line († G.robusta);(7)transverse dorsal sulci of mesosoma broad, separating the meso- and metanota and the metanotum and propodeum by at least one tarsomere width; vs. these sulci not as broad, with the meso- and metanota and the metanotum and propodeum separated by less than one tarsomeral width († G. spiralis, † G. subcuspis) [Note 1]; and (8) propodeal spiracle covered anteriorly by an anterior flange which is directed posterolaterally; vs. spiracle not flanged († G. spiralis, † G. subcuspis; state uncertain for † G. robusta) [Note 3]. Notes on the diagnosis Note 1: † Gerontoformica gracilis is quite similar overall to † G. spiralis and † G. subcuspis. The primary structural distinction is the width of the dorsal transverse sulci that divide the mesonotal and metanotal regions, and the metanotal region and the propodeum, as well as development of an anterior flange around the propodeal spiracles. The character used by Barden & Grimaldi (2014) to distinguish † G. spiralis and † G. gracilis was the distance between the pro- and mesocoxae (their couplet 9); this is certainly a matter of preservation, as the prothorax of the holotype of † G. gracilis is elevated relative to the mesothorax, and the coxae are promoted anteriorly. Such pronotal elevation is possible in ant species with a mobile promesonotal articulation. The defining feature of † G. subcuspis provided by Barden & Grimaldi (2014) is the form of the subpetiolar process, which has an almost vertically oriented anterior margin in profile view. The process of † G. gracilis is more evenly rounded from posterior to anterior, while that of † G. spiralis is not visible. These distinctions should be re-evaluated in future study. See also Note 3 on the synopsis of † Gerontoformica classification above. Note 2: We do not know the distribution of the process of the proximal labial palpomere across † Gerontoformica, with the exception of its absence in † G. sternorhabda. Despite this, we note the development of these processes as they are unique to our knowledge of both extant and extinct species. Because of the difficulty of evaluating proximal palpomeres for ants in general, and especially for fossil ants, we strongly recommend the application of µ-CT methods to determine the phylogenetic extent of this obvious apomorphy. Note that it is possible that the holotype lacks this condition, as we discovered this character after our chance to directly examine the type specimen. Note 3: The anterior flange or hood of the propodeal spiracle is present in most † Gerontoformica examined, with the exception of † G. spiralis and † G. subcuspis. The flange could not be evaluated for † G. magna or † G. robusta. Measurements and indices Adult, specimen C-32: HWed = 0.71; HWev = 0.78; EWl = 0.17; HD = 0.62; ML = 1.49; PnLi = 0.59; PnWa = 0.18; MnL = 0.35; AIIILm = 0.52; AIIILl = 0.65; HPI = 0.99; HSI = 0.47; AIIILI = 0.80. Pupa, specimen C-31: HWed = 0.72; HWev = 0.71; EWl = 0.18; HD = 0.62; ML = 1.62; PnLi = 0.60; PnWa = 0.25; MnL = 0.34; AIIILm = 0.62; AIIILl = 0.73; HPI = 0.86; HSI = 0.44; AIIILI = 0.85. Redescription: adult Head: The head is narrow in facial view, i.e. it is lateromedially narrower than anteroposteriorly long as measured from the anterior clypeal margin to the apparent posterior head margin (Fig. 2K); in posterior and lateral view, the head is dorsoventrally broad, with the vertexal region dome-like; standing setae are most conspicuous on the clypeus. The compound eyes are situated in the posterior third of the head; they bulge laterally, breaking the silhouette of the lateral head margins in facial view; their height mesonotal carina; mspct, mesopectus; mtbt, metabasitarsus; mtcx, metacoxa; mtfm, metafemur; mtnt, metanotum; mtpfm, metaprefemur; mtplglvf, ventral flange of the metapleural gland; mtptc, metapretarsal claw; mttbsa, anterior spur of metatibia; mttbsp, posterior spur of metatibia; mttr, metatrochanter; pd, pedicel; pl, labial palp; pm, maxillary palp; pbt, probasitarsus; pnt, pronotum; ppd, propodeum; ppdsf, anterior flange of propodeal spiracle; pptc, propretarsal claw; pt, petiole; ptn, petiolar node; pts, petiolar sternum; ptsp, subpetiolar process; sc, scape; tgl, laterotergite; to, antennal torulus. above the surrounding surfaces of the cranium is comparatively high; their ommatidia count appears similar to that of † G. sternorhabda; they are apparently glabrous, i.e. lacking interstitial setation. The three ocelli are completely developed. The frontal carinae diverge posterolaterally toward but not reaching the compound eyes; they are circular in form, i.e. curving evenly from their anterior termini to their posterior termini which are directed anterolaterally, rather than posterolaterally; their anterior termini are distant from the epistomal line; the minimum distance between the frontal carinae is about 0.26× maximum head width as measured in full face view. The antennal scrobes are anteroposteriorly short and encircled by the frontal carina. The antennal toruli are distant from the posterior clypeal margin; they are in the form of a low, more-or-less even ring. The antennae are 12-merous. The scapes are somewhat flattened and curved; they are about four times as long as their maximum width; their length is somewhat more than half the width of the head, and somewhat less than half the length of the head; they lack standing setae along their shafts. The pedicels are slightly longer than twice their width; they are about one-third the length of the scapes, and about half the length of the third antennomere; they apparently lack standing setae. The flagellae are longer than the mesosoma and are simple, i.e. not thickening distally; they bear a range of standing and appressed setae; flagellomeres I are the longest, being somewhat more than four times as long as wide and about three fourths the length of the scape; flagellomeres II–IX are all longer than the pedicel; flagellomeres X are longer than each pair of flagellomeres from II to IX. The clypeus is about three times as wide lateromedially as long anteroposteriorly, with the length measured from the midpoints of the anterior and posterior clypeal margins and the width measured between the lateralmost points of the clypeus. The lateroclypeal areas are formed as lateral lobes. The medioclypeal area is anteriorly convex; its length at the midline of the head is about 0.21× head length also at midline, as measured in full-face view; it bears an array of standing (rather than appressed) setae on its disc and is margined anteriorly by chaetae. The mandibles are simple and apically bidentate. The maxillary palps are 6-merous (Figs 2B, H, 7A–D) [Note 1]; they are elongate, being almost as long as the head and longer than the scapes and mandibles; the proximal palpomeres are short compared to the others; the second palpomeres are dorsoventrally flattened and lobate apicomedially; the third through sixth palpomeres are long, thin, and cylindrical. The labial palps are 4-merous (Figs 2B, H, 7A–D) [Note 1]; they are short, being less than half the length of the maxillary palps, and with their individual lengths shorter than each of the maxillary palpomeres with the exception of the proximal maxillary ones; the proximal labial palpomere is narrow proximally and bears a distinct lobate process medially at about its apical third, with this process being about as long as wide; the second and third palpomeres are thickened medially; the fourth palpomeres are relatively more cylindrical. Mesosoma: The pronotum bears an anteromedian neck process, and lateral and posteromedian flanges; these flanges are not flared; the muscular node or ‘disc’ of the pronotum is hemispherical as observed in lateral view and almost elliptical in dorsal view, being distinctly longer than tall in lateral (profile) view, thus appearing narrow; setation was not observed on the pronotum [Note 2]. The pronotal lobes are well developed (Fig. 6E). The mesonotum is not divided into an anterior mesoscutal area and a posterior mesoscutellar area, i.e. the transverse mesonotal carina is not developed; the notum is convex in lateral view and is almost flattened along most of its length. The mesopectus is not clearly divided into dorsal and ventral areas; its dorsoventral height is almost 1.5× that of its anteroposterior length. The transverse mesonotal sulcus is anteroposteriorly long/broad. The metanotum is developed as a distinct and almost evenly convex bulge. The transverse metanotopropodeal sulcus is anteroposteriorly broad and continues ventrally toward the base of the mesocoxa, completely separating the lateral metapectal area from the lateral mesopectal area. The metapleural gland orifice is small and not remarkably hairy (Fig. 6F); it does not have a distinct bulla; it is margined dorsally and ventrally by flanges, including the ventral metapleural gland flange. The propodeum is rounded, with the dorsal and posterior margins curving broadly into one another in lateral view; its posterior surface is convex; it does not, apparently, bear standing setae. The propodeal spiracles are situated distant from the metanotum and below the dorsal propodeal margin as seen in lateral view, but they are located in the anterodorsal fourth of the sclerite. The propodeal lobes are apparently not developed. Legs: The legs are developed as expected for the Formicidae, with some notable characters and states. With the exception of the tibial apex and tarsi, they appear almost entirely glabrous. The state of the apical protibial foramina is uncertain. The mesoprefemora and metaprefemora are welldeveloped and are broader ventrally than dorsally. The protibia bears and anterior brush of dense suberect setae in their apical third, near the calcar. Each of the mesotibia and metatibia bear a pair of apicoventral spurs; the anterior tibial spurs are barbirulate; the posterior tibial spurs are simple. The calcar is apparently bifid apically, with one point being the apex of the elongate velum and the other point being a small array of hairs; two stout setae are developed posterior to the calcar. The plantar lobes of the tarsi are well developed, the ventral setation is sparse, and the apical row of chaetae is thinner. The fourth tarsomeres are only weakly notched distally, thus appearing cylindrical in dorsal view. The pretarsal claw teeth are well developed and located just past the midlength of their respective claws. The aroliae are well developed and comparatively large (Fig. 8D); they are nearly as long as the pretarsal claws. Metasoma: The petiole is nodiform and lacks tergosternal fusion between its postsclerites. The petiolar tergum is anteroposteriorly longer than dorsoventrally tall; it is asymmetrically convex, being somewhat longer anteriorly than posteriorly. The developmental state of the laterotergites is uncertain. The petiolar sternum is anteriorly flat; its main portion is at least twice as long as tall; it is narrowly convex in cross-section at its midpoint; it is weakly produced anteroventrally as a low, lobate subpetiolar process, which is shorter dorsoventrally than wide anteroposteriorly; posteriorly, the sternum is not distinctly concave or notched. The helcium is narrow relative to the third abdominal postsclerites; the helcial tergite conceals the helcial sternite in lateral view. The abdominal posttergite III is not constricted posteriorly and is not fused with the third poststernite; it is not necked or shouldered anteriorly, as the tergum evenly curves from its anterior base to posterior margin in lateral view. The abdominal tergosternal margin III is weakly curved, without distinct ‘shouldering’ as observed in various Formicinae and Dolichoderinae. The abdominal poststernite III is not constricted posteriorly, but is weakly angled lateromedially, and bears the prora anteroventrally. The prora is lip-like in lateral view, being anteroposteriorly short and moreor-less transverse in ventral view. The abdominal segments IV, V, and VI are not divided into pre- and postsclerites by a cinctus; they are homonomous in form, i.e. highly similar in shape, size and other qualities of appearance. The seventh abdominal tergum is somewhat dome-like. The seventh abdominal sternum is lateromedially cupped and narrowed distally. The sting is long and narrow. The third valvulae are digitate in form and highly exserted as preserved. Preservation: The specimen CASENT0741232 is exceptionally well preserved internally, particularly the head and mesosoma (Fig. 9). The metasoma is, however, less well preserved, and has some apparent fungal growth or decay bubbling emanating from between the third and fourth abdominal segments. There are several fractures around the specimen, including on the dorsal surface of the head, the ventral right side of the head, across the left side of the mesosoma, and across the petiole and the left side of the third and fourth abdominal segments. The right side of the face, opposite from where the scape is held, is indented, thus appearing to have a longitudinal scrobe (Fig. 10); this is definitely an artefact, as it is not symmetrically present on the left side of the face where the scape is preserved in a position that is distant from the head capsule. Similarly, the mesosoma is indented where the legs are in close proximity (Fig. 10). The left metatrochanter appears distorted in shape. Notes on description Note 1: The original description recognized 4-merous maxillary palps and did not state a labial palpomere count. A 6, 4 palp formula (sensu Bolton, 1994, 2003) was determined here based on direct examination of the holotype, and from our microphotographs and digital renders. As noted in the diagnosis, the process of the proximal labial palpomere is unique among † Gerontoformica, given our current knowledge. Note 2: We are not certain whether † G. gracilis is largely glabrous or whether it has appressed pubescence in various places. At the least we expect pubescence on inter-sclerite contact surfaces. Description: pupa The pupa (Figs 2A, D, G, J, 7, 10) is encased in a cocoon with a black meconium at the caudal end (Fig. 1A). Most structures of species-level identificatory value are incompletely developed, including the frontal carinae, perioral sclerites, mesosomal dorsum and anterior metasoma. The preservation of the specimen is fine externally but is poor internally, with the body cavity filled with a single, solid mass, despite apparent distinctions as seen from light microscopy. In overall appearance, the specimen is relatively bubbly or puffy looking, and has the propodeum crushed and incompletely differentiated from the petiole. Those metasomal segments which are posterior to the petiole are bulging, thus they appear slightly constricted as with a cinctus, but cincti are apparently absent. The metanotal and propodeal spiracles are visible externally, but those of the metasoma are not. Features of note include the following: The head is longer anteroposteriorly than broad lateromedially; the mandibles are contacting one another apically; the maxillolabial complex is exserted, with the palps and glossa clearly visible in ventral view; the maxillary palps are 6-merous; the labial palps are 4-merous; the antennae are directed caudally and reach the posterior margin of the third abdominal segment; the pronotum is longer than tall in lateral view; and the mesonotum lacks a transverse ridge, thus is not divided into anterior mesoscutal and posterior mesoscutellar regions. The pupa differs from the synincluded adults of both species as follows: The antennae appear wideset; the clypeus is anteroposteriorly longer, apparently with an additional band of cuticle along the anterior m a r g i n; t h e m a n d i b l e s a r e o b l i q u e l y o r i e n t e d relative to head length, converging anterad (vs. perpendicular to the long axis of the head at closure); and the labrum is apically notched and with distinct paramedian lobes. Remarks on the pupa Because little comparative work on pupal morphology has been done in Formicidae, it is basically unknown what the polarity of the ‘general features of note’ is within the family. Further, because there are no developmental series of anatomy available for pupal transformation, we cannot be certain of the stage that this specimen was preserved. The conditions listed above which differ between the pupa and adults are especially interesting, as they suggest that there are intermediate stages in the structural rearrangement of the body. For example, the wideset toruli and exceptionally long clypeus are hard to explain without an atlas of developmental transformation. We note the apically bilobate labrum, in particular, as the labra of the adults are apically rounded. At present we are unable to explain the labral difference, as there are no wo, Published as part of Boudinot, Brendon E., Richter, Adrian, Katzke, Julian, Chaul, Júlio C. M., Keller, Roberto A., Economo, Evan P., Beutel, Rolf Georg & Yamamoto, Shûhei, 2022, Evidence for the evolution of eusociality in stem ants and a systematic revision of † Gerontoformica (Hymenoptera: Formicidae), pp. 1355-1389 in Zoological Journal of the Linnean Society 195 on pages 1369-1377, DOI: 10.1093/zoolinnean/zlab097, http://zenodo.org/record/6994456, {"references":["Barden P, Grimaldi D. 2014. A diverse ant fauna from the mid-Cretaceous of Myanmar (Hymenoptera: Formicidae). PLoS One 9: e 93627.","Barden P, Grimaldi D. 2016. Adaptive radiation in socially advanced stem-group ants from the Cretaceous. Current Biology 26: 1 - 7.","Bolton B. 1994. Identification guide to the ant genera of the world. Cambridge: Harvard University Press, 222.","Bolton B. 2003. Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute 71: 1 - 370.","Boudinot BE, Moosdorf OTD, Beutel RG, Richter A. 2021 b. Anatomy and evolution of the head of Dorylus helvolus (Formicidae: Dorylinae): patterns of sex- and castelimited traits in the sausagefly and the driver ant. Journal of Morphology 282: 1616 - 1658. Doi: 10.1002 / jmor. 21410."]}

† GERONTOFORMICA STERNORHABDA SP. NOV. (FIGS 1C, D, 2C, F, I, L, 4– 6, 7E, F, 11 (1-2), 12(2-1, 2-3, 2-4), 13(3’-1); SUPPORTING INFORMATION, FIGS S1, S 2) Z o o b a n k r e g i s t r a t i o n: u r n: l s i d: z o o b a n k. org:act: E77C1A20-1398-465F-9607-AD11E97ADF1C Type material: Holotype. Wingless female (w). Myanmar, Kachin State: Hukawng Valley [CASENT 0741233 in an amber piece labelled AMNH SY-23 and deposited at AMNH]. Paratypes. Wingless females (w). Synincluded with holotype [CASENT0741234]; same locality as synincluded holo- and paratypes [UFV-LABECOL-009656, deposited in CELC]. Diagnosis (wingless female) Conforming to the diagnosis of the Formicidae (see: Boudinot et al. 2020a, b), including the following key conditions: (1) postgenal bridge elongated, thus head ‘prognathous’ (Fig. 2C); (2) cranial condyles of the anterior/ dorsal mandibular articulation enlarged (Fig. 5B); (3) toruli oriented dorsolaterally rather than simply dorsally (Fig. 5A); (4) procoxae elongate, about twice as long as wide (Fig. 2C); (5) prodisticoxal foramen ‘closed’ and protrochanter narrowly necked (Fig. 4F) [Note 1]; (6) meso- and metathoracicocoxal articulations ‘closed’, i.e. directed ventrally rather than laterally or ventrolaterally (Fig. 4F); (7) abdominal segment II completely petiolated (Fig. 4F); (8) subpetiolar process present (Fig. 4F); (9) prora present (Fig. 4F). I. Among Formicidae, identifiable as †Sphecomyrminae: (1) Mandibles simple and bidentate (Fig. 5A), without: (a) being strongly bowed and multidentate as in the † Camelomecia group, (b) the scythe-like blade as in the haidomyrmecine † Haidomyrmex clade, (c) projecting anteriorly with numerous teeth as in the haidomyrmecine † Aquilomyrmex clade, or (d) the strong torsion of † Zigrasimeciini (the state in † Boltonimecia is uncertain); (2) the antennal scrobes on the face do not extend all the way to the compound eye (Fig. 4B) (such scrobes observed in †Zigrasimeciinae, including † Boltonimecia) [Note 2]; (3) anterolateral corners of head not produced as robust triangles (Fig. 5A) (such corners observed in † Dilobops of the †Haidomyrmecinae); and (4) (a) scapes shorter than the width of the head (Fig. 5A) and (b) clypeus not extending posteriorly between the toruli (Fig. 2L) (such extension observed in † Brownimeciinae); II. Within †Sphecomyrminae, identifiable as † Gerontoformica : (5) anteromedian clypeal margin not produced as distinct medial lobe (Fig. 2L); vs. such a lobe present († Sphecomyrma, † G. tendir) [Note 3]; and (6) (a) mandibles short and fitting against clypeus when closed (Fig. 5A) and (b) metanotum developed (Fig. 2C); vs. mandibles elongate and metanotum not developed († Myanmyrma); III. Within † Gerontoformica, with the following unique condition : (7) the anteroventral (‘subpetiolar’) process of the petiolar sternum long, orthogonal to the longitudinal axis of the petiole, and more-or-less rod-like, i.e. with anterior and posterior margins parallel to subparallel (Fig. 2C); vs. short and triangular († G. gracilis, † G. occidentalis, † G. pilosa, † G. robusta, † G. rugosa, † G. spiralis, † G. subcuspis, † G. tendir) [Note 4]; IV. Within † Gerontoformica, identifiable as a member of the pilosa species group : (8) mesoscutum with distinct, raised transverse carina separating mesoscutal and mesoscutellar regions (Fig. 6B); vs. such a carina entirely absent or only poorly developed laterally, thus incomplete medially and not forming a distinct angle between the mesoscutal and mesoscutellar regions in profile view (cretacica, gracilis groups); (9) tergum of petiolar node anteroposteriorly longer than dorsoventrally tall (Fig. 2C); vs. petiolar node tergum taller than long (cretacica group); and (10) abdominal segment IV (metasomal III) with the cinctus distinct and impressed, i.e. divided into pre- and post-sclerites by a transverse sulcus (Fig. 5E); V. Within the pilosa species group, distinguished from all species by the following : (11) cinctus developed, but transverse sulci weakly impressed, thus pre- and postsclerites of abdominal segment IV not meeting at strongly oblique angle (Fig. 5E); vs. transverse sulci deeply impressed, thus pre- and postsclerites meeting at distinct oblique angle († G. contega, † G. magna, † G. pilosa); (12) head in full-face view broader lateromedially than long anteroposteriorly, excluding eyes (Fig. 2L); vs. head longer than broad († G. contega, † G. magna, † G. pilosa) [Note 5]; (13) pretarsal claws edentate (Fig. 5G, I, J); vs. each claw with a single tooth of variable location († G. contega, † G. magna, † G. pilosa) [Note 6]; and (14) body small, mesosoma length 1.5 († G. contega, † G. pilosa) and> 2.5 († G. magna); VI. Further distinguished by species in the pilosa group by the following : (15) anteromedian clypeal margin distinctly evenly curved to an ‘incision’ at the point of contact with the rounded lateroclypeal lobes (Fig. 2L); vs. anteromedian clypeal margin weakly convex, without distinct incision between the medioclypeus and lateroclypeal lobes, which are themselves anterolaterally angled († G. contega); (16) in profile, pronotum evenly curved, mesoscutum more-or-less aligned with mesoscutellum and metanotum, and propodeal dorsal and posterior surfaces curving into one another obliquely (Fig. 2C); vs. pronotum, mesonotum, and propodeum each shouldered in appearance, i.e. pronotum with strong anterior dorsolateral bulge, mesonotum with mesoscutal and mesoscutellar regions meeting at nearly a right angle, and propodeal dorsal and posterior surfaces also meeting at nearly a right angle († G. contega); (17) standing setation on body short, relatively sparse (with the exception of the propodeum and petiolar tergum) (Fig.5); vs. longer setation present († G. magna, † G. pilosa); and (18) anteroventral process of abdominal sternum III (metasomal II) robust but short anteroposteriorly (Fig. 2C); vs. prora anteroposteriorly long, sharkfin-like in form († G. pilosa) [Note 7]. Notes on the diagnosis Note 1: The right procoxa and protrochanter of the holotype are slightly disarticulated. However, the focal details to evaluate are the circular shape of the prodisticoxal foramen and the crank-like (curved) and thin proximal neck of the protrochanter, which can be evaluated from Figure 4F. Note 2: The only species of †Sphecomyrminae to have an elongate antennal scrobe is † G. contega. Although the scrobe of this species was observed via direct examination of the holotype, it remains a possibility that this is an artefact because other specimens of † Gerontoformica may have asymmetrical, sulcuslike distortions of the head corresponding to the position of the scrobe (see the ‘preservation’ section of the † G. gracilis description; Fig. 10). Conducting a µ-CT scan of the type specimen and/ or the accrual of additional specimens are necessary. N o t e 3: T h e a n t e r o m e d i a n c l y p e a l p r o c e s s o f † Sphecomyrma is lateromedially thin and at least as long as broad; it is distinctly bordered laterally by the medioclypeus, i.e. the clypeal ‘disc’ between the lateral clypeal lobes. In contrast, the entire medioclypeus of † G. tendir is apparently produced. See Note 5 of the ‘Notes on classification’ section above. Note 4: The form of the subpetiolar process is unknown for four species within the genus: † G. contega, † G. cretacica, † G. magna and † G. orientalis. Note 5: Although it is difficult to evaluate the head shape of † G. contega from the holotype due to cut of the amber matrix, the head does appear to be longer than broad. Reevaluation of this condition through µ-CT is recommended. Note 6: Teeth on the pretarsal claws have been recorded for most species of † Gerontoformica († G. contega, † G. gracilis, † G. magna, † G. occidentalis, † G. pilosa, † G. robusta, † G. spiralis and † G. subcuspis). The condition of having reduced teeth on the pretarsal claws, however, is shared with † G. cretacica and † G. tendir. Notably, Perrichot et al. (2008) recorded minute teeth on the pretarsal claws of † G. occidentalis, which suggests the need to re-evaluate the holotype of † G. cretacica. Note 7: The prora is clearly an important structural feature for distinguishing stem ants but is not clearly visible in most specimens, including † G. contega and † G. magna in the pilosa group, † G. cretacica and † G. orientalis in the cretacica / orientalis group, plus † G. rugosa and † G. tendir. It is extremely small and nearly absent in † G. gracilis and † G. occidentalis, and it is developed, but short and comparatively inconspicuous in † G. robusta, † G. spiralis, and † G. subcuspis. MEASUREMENTS AND INDICES Holotype, specimen C-33: HWed = 0.87; HWev = 0.95; EWl = 0.14; HD = 0.55; ML = 1.25; PnLi = 0.50; PnWa = 0.30; MnL = 0.27; AIIILm = 0.48; AIIILl = 0.53; HPI = 0.64; HSI = 0.69; AIIILI = 0.91. Paratype, specimen C-34: HWed = 0.94; HWev = 1.06; EWl = 0.20; HD = 0.66; ML = 1.39; PnLi = 0.45; PnWa = 0.27; MnL = 0.28; AIIILm = 0.50; AIIILl = 0.64; HPI = 0.70; HSI = 0.67; AIIILI = 0.78. UFV-LABECOL-009656: HWed = 0.79; HWev = 0.85; EWl = 0.11; HD = 0.46; ML = 1.05; PnLi = (~0.35–0.38); PnWa = –; MnL = 0.29; AIIILm = 0.4; AIIILl = 0.48; HPI = 0.58; HSI = 0.75; AIIILI = 0.83. Description Head: The head is broad in facial view, i. e. lateromedially wider than anteroposteriorly long from the anterior clypeal margin to the apparent posterior head margin (Fig. 2L); in posterior or lateral view, the head is dorsoventrally narrow, with the vertexal region not being particularly domed; standing setae are present on the vertexal and facial regions [Note 1]; there are short, decumbent setae distributed sparsely on the head capsule, a few longer, and suberect setae medially on the vertex near the ocelli. The compound eyes are situated in the posterior third of the head (Fig. 2L); they bulge laterally, breaking the silhouette of the lateral head margins in facial view; their height above the surrounding surfaces of the cranium is comparatively low; they comprise over 100 ommatidia, but not more than 200 (Fig. 4C) [Note 2]; they are apparently glabrous, i.e. lacking interstitial setation. The three ocelli are completely developed (Fig. 2L). The frontal carinae diverge posterolaterally, toward but not reaching the compound eyes (Figs 2L, 5A); they are sinuate in form, i.e. from their anterior margins they are directed relatively medially then bulge laterally before curving laterad; their anterior termini are close to the epistomal line, but not extending on to the clypeus; the minimum distance between the frontal carinae is about 0.29× maximum head width as measured in full face view. The antennal scrobes, or depressed contact surfaces of the face laterad the frontal carinae, are parallel in orientation relative to the frontal carinae and are apparently longer than wide (Figs 2L, 4B). The antennal toruli abut but do not indent the posterior clypeal margin [Note 3]; they are in the form of a low, more-or-less even ring. The antennae are 12-merous (Fig. 4B). The scapes are somewhat flattened and curved (Fig. 2C, F, I, L); they are about three to four times as long as wide (Fig. 2I); their length is about half the width of the head, and less than half the length of the head; they bear a vestiture of short subdecumbent to suberect setae. The pedicels are about twice as long as wide (Fig. 4F); they are about one-third the length of the scapes, and somewhat more than half the length of the third antennomere; their setation is similar to that of the scapes. The flagellae are longer than the mesosoma and are simple, i.e. not thickening distally (Fig. 4F); they bear a range of standing and appressed setae; flagellomeres I are the longest, being about four times as long as wide and more than half the length of the scapes; flagellomeres II–IX are about as long as the pedicel; flagellomeres X are longer than flagellomeres II–IX. The clypeus is about four times as wide (lateromedially) as long (anteroposteriorly), with the length measured from the midpoints of the anterior and posterior clypeal margins and the width measured between the lateralmost points of the clypeus (Fig. 2L). The lateroclypeal areas are formed as lateral lobes (Figs 2L, 5A). The medioclypeal area is anteriorly convex (Fig. 2L); its length at the midline of the head is about 0.21× head length also at midline, as measured in full-face view; it bears five or six long and flexuous setae that are situated near the anterior clypeal margin and anteriorly directed, consisting of one medial seta surrounded by a pair of setae and potentially a second, even more lateral pair [Note 4]; the anterior medioclypeal margin bears a row of chaetae. The mandibles are simple and apically bidentate (Fig. 5A). The maxillary palps are 5-merous (Figs 2I, 4A, 7E, F) [Notes 5, 6]; they are conspicuously short, with their total lengths shorter than the lengths of either the mandibles or scapes; with the exception of the apical palpomere, they are thick and bulging at about their midlengths; they are adorned with erect and appressed pilosity. The labial palps are 4-merous (Figs 2I, 4A, 7E, F) [Note 6]; they are short, being just over half the length of the maxillary palps; with the exception of the apical palpomere, they are more-orless conical and thickening toward their apices; they are adorned with erect and appressed pilosity; the proximal palpomere lacks a distinct process. Mesosoma: The pronotum bears an anteromedian neck process, and lateral and posteromedian flanges (Figs 2C, F, 5C, 6A); these flanges are flared in the paratype specimen C-34 (Fig. 4C) but not in the holotype or other paratype; the muscular node or ‘disc’ of the pronotum is almost spheroidal in shape, with the lateral margins strongly convex in dorsal view and the dorsal margin strongly convex in lateral view, and with an anteroposterior length approximating its dorsoventral height; pronotal setation is sparse, being represented by a few subdecumbent setae (Fig. 6A). The pronotal lobes are well developed (Fig. 6A) [Note 7]. The mesonotum is divided into an anterior mesoscutal area and a posterior mesoscutellar area by the transverse mesonotal carina (Figs 2C, F, 4C, F, 5C, 6B). The mesoscutal area is approximately in the form of a low saddle (i.e. is a low hyperbolic paraboloid), with a concave dorsal margin in lateral view, and with the anterior rim more upcurved than the posterior rim (Fig. 2C). The mesoscutellar area is convex, but sunken relative to the mesoscutal area (Fig. 2C). The mesopectus is divided into dorsal and ventral areas by a longitudinal sulcus (Fig. 2C); its dorsoventral height is about equal to its anteroposterior length. The dorsal mesopectal area is approximately rectangular in shape, being somewhat more than twice as long anteroposteriorly as tall dorsoventrally (Fig. 2C); its dorsoventral height is one-third the dorsoventral height of the lower mesopectal area as measured from the transverse sulcus directly ventrad to an imaginary line drawn parallel to the ventrolateral margins of the meso- and metapecta. The ventral mesopectal area is approximately triangular in shape, being broad along is dorsal margin and narrowing posteroventrally to its ventrolateral margin (Fig. 2C); its anteroposterior length along its dorsal margin is approximately equal to its dorsoventral height. The transverse mesometanotal sulcus is anteroposteriorly short/ thin (Fig. 2C). The metanotum is developed as a distinct bulge between the metanotal spiracles (Fig. 2C). The transverse metanotopropodeal sulcus is anteroposteriorly long/ broad and continues ventrally toward the base of the mesocoxa, completely separating the lateral metapectal area from the lateral mesopectal area (Fig. 2C). The metapleural gland orifice is large, hairy, and in the form of a broad subelliptical pit (Fig. 6B); it is margined dorsally by a bulge, the metapleural gland bulla, and ventrally by the ventral metapleural gland flange, which itself is a continuation of the sinuate ventrolateral carina of the metapectus and is spiniform and dorsally inclined. The propodeum is boxy (Figs 2C, 6B) [Note 8]; it bears standing setae and is the hairiest mesosomal region. The propodeal spiracles are situated distant from the metanotum, but near the dorsal propodeal margin in lateral view (Figs 2C, 5C); they are posteriorly to posterolaterally directed and protected anteriorly by the anterior flange of the propodeal spiracles. The propodeal lobes are apparently not developed. Legs: The legs are developed as expected for the Formicidae, with some notable characters and states. They are densely hairy, appearing shaggy, with the setae suberect (Fig. 4A, D, G–J). Apparently, the apical protibial foramina are open, i.e. without a bridge of sclerite dividing the calcar from the probasitarsus (Fig. 5G) [Note 9]. The mesoprefemora and metaprefemora are well developed and are broader ventrally than dorsally (Fig. 5D). The protibia bears and anterior brush of dense suberect setae in their apical third, near the calcar (Fig. 4A). Each of the mesotibia and metatibia bear a pair of apicoventral spurs (Figs 4I, H, 5H); the anterior tibial spurs are pectinate; the posterior tibial spurs are barbirulate to simple. The calcar is apparently bifid apically, with one point being the apex of the elongate velum and the other point a small array of hairs (Fig. 5G); two stout setae are developed (inserted) posterior to the calcar. The plantar lobes of the tarsi are not developed (absent), but the tarsomeres have a brush of dense ventral setae, and are apically margined by thick, coarse chaetae (Figs 4G–J, 5G–J) [Note 10]. The fourth tarsomeres of each leg are deeply notched distally, thus appearing V-shaped (probasitarsi) or arrowhead-shap, Published as part of Boudinot, Brendon E., Richter, Adrian, Katzke, Julian, Chaul, Júlio C. M., Keller, Roberto A., Economo, Evan P., Beutel, Rolf Georg & Yamamoto, Shûhei, 2022, Evidence for the evolution of eusociality in stem ants and a systematic revision of † Gerontoformica (Hymenoptera: Formicidae), pp. 1355-1389 in Zoological Journal of the Linnean Society 195 on pages 1364-1369, DOI: 10.1093/zoolinnean/zlab097, http://zenodo.org/record/6994456, {"references":["Boudinot BE, Khouri Z, Richter A, Van de Kamp T, Barden P, Perrichot V, Chaul JCM. 2020 a. Chapter II. The evolution of the ants: extinct ant sister-group illuminates eusociality origin and post-K / Pg persistence. In: Boudinot BE, Systematic and evolutionary morphology: case studies on Formicidae, Mesozoic Aculeata, and hexapodan genitalia. Ph. D. Thesis, University of California, Davis, 174 - 393.","Perrichot V, Nel A, Neraudeau D, Lacau S, Guyot T. 2008. New fossil ants in French Cretaceous amber (Hymenoptera: Formicidae). Naturwissenschaften 95: 91 - 97.","Bolton B. 2003. Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute 71: 1 - 370.","Beutel RG, Gorb SN. 2001. Ultrastructure of attachment specializations of hexapods (Arthropoda): evolutionary patterns inferred from a revised ordinal phylogeny. Journal of Zoological Systematics & Evolution Research 39: 177 - 207.","Boudinot BE, Beutel RG, Gorb SN, Polilov AA. 2021 a. Functional diversity of attachment and grooming structures is retained in all but the smallest insects. Journal of Zoology 313: 99 - 113.","Wohrl T, Richter A, Guo S, Reinhardt L, Nowotny M, Blickhan R. 2021. Comparative analysis of a geometric and an adhesive righting strategy against toppling in inclined hexapodal locomotion. Journal of Experimental Biology 224: jeb 242677.","Bolton B. 1994. Identification guide to the ant genera of the world. Cambridge: Harvard University Press, 222."]}

Genus Metalasius gen.nov. ZooBank LSID. urn:lsid:zoobank.org:act:AC5A1489-C805- 4035-A1C0-3DDBC6E1206D. Type species. Lasius myrmidon Mei, 1998: 177, figs 1���11 (w.). Original designation. Species included. M. myrmidon (Mei, 1998) comb.nov., ��� M. pumilus (Mayr, 1868) comb.nov. Total clade definition (worker). 1. With characters of Lasiini. 2. Mandible with 6���8 teeth. 3. Palp formula 6,4. 4. Basal and masticatory mandibular margins meeting at a weakly oblique angle. 5. Clypeus modified for reception of labrum (specifically, clypeus with anterolateral notches; Note 1). 6. Frontalcarinae conspicuous, > 0.5 �� anteroposteriorantennal torulus diameter. 7. Frontal region of head, between antennal toruli strongly bulging, frontalcarinae raised above toruli (Note 2). 8. Antenna 12-merous. 9. Third antennomere broader than long (Note 3). 10. Compound eyes set at about head midlength. 11. Ocelli absent. 12. Dorsum of head completely without standing setae or with only a few small setae around each posterolateral head corner (Note 4). 13. Mesonotum, metanotum and/or propodeum discontinuous, metanotum undifferentiated medially. 14. Mesopleural anterodorsal margin, near posterolateral region of pronotum, inconspicuously bulging, this weak shoulder a very narrow groove which traverses the mesosternum. 15. Metapleural gland very small, orifice directed almost completely posteriorly (Note 5). 16. Propodeal spiracle situated in lower 2/3 of propodeum. 17. Legs entirely or almost entirely devoid of standing setae. 18. Petiole with raised squamiform node, without posterior elongation. 19. Abdominal tergum III vertical, without deep groove for receiving petiole; not concealing petiole when gaster raised (Note 6). 20. Tergosternal suture of abdominal segment III not raised dorsally before unfusing near spiracle, rather anterior margin of abdominal sternum III directed anteriorly away from helcium before narrowly curving posteriorly (Note 6). 21. Pubescence of abdominal terga VI and VII linear. Notes on definition: Note 1. Modification of the anterior clypeal margin for reception of the labrum is here interpreted as a synapomorphy of Metalasius plus the core Prenolepis genus group. The modification is most easily observed in anterior or anterodorsal view. In most Formicinae, the perceived anterior clypeal margin with the head in full-face view is usually a carina which runs across the clypeus from the lateral clypeal margins.This carina may be raised or otherwise modified; regardless, the carina itself or the anterior region of the clypeus is produced anteriorly, concealing the clypeolabral articulation. In the Prenolepis and Metalasius genus groups, the clypeolabral articulation is usually exposed or nearly exposed laterally by notches in the anterior clypeal carina, although it may be exposed medially where the anterior clypeal carina is absent. Note 2. See Note 1 for the Lasius genus group. Note 3. Surprisingly, this distinguishes members of the Metalasius genus group from most formicine genera, with the exception of some Myrmelachista, various plagiolepidines and the Lasius flavus group. Cladomyrma species have a cone-shaped third antennomere, which is usually longer than the diameter of its base (and often apex), except in C. dianeae Agosti et al. for which the length and basal diameter are subequal. Some Pseudolasius and Paraparatrechina approach having subequal diameter and length. Note 4. Mei (1998), in his diagnosis of Metalasius myrmidon, indicated that these standing setae were absent except for one specimen. Note 5. This state may be a synapomorphy for the clade consisting of Metalasius plus the Prenolepis genus group. It was not possible to evaluate this with confidence for ��� M. pumilus, but from the dorsal view of specimen SMFBE1226 on AntWeb, the gland does appear to be small. Note 6. These characters could not be evaluated with confidence for ��� M. pumilus with the available material or descriptions. Etymology. A combination of the Greek ���meta-��� (with, across, after) and ���l��sios��� (hairy), in reference to the former placement of the type species. Homophonously forming ���metal-Asius���, invoking the death of the Trojan leader Asius during the assault on the Archaean wall of Troy. Masculine. Comments. Although, we could not evaluate all of these characters for ��� M. pumilus, this species is consistently recovered as sister to M. myrmidon in combined analysis (Figs 4, S 7���S 9). Metalasius is most easily differentiated from both the Lasius and Prenolepis genus groups by the combination of mid-set eyes, the posteriorly directed and reduced metapleural gland orifice, raised frontal carinae and almost complete lack of standing setae on the head. In addition, both included species of Metalasius have broad third antennomeres and unusually small bodies relative to Lasius, being < 2 mm in total length (Mei, 1998; Dlussky, 2011)., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on pages 140-141, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Mei, M. (1998) Lasius (Cautolasius) myrmidon n. sp.: a new hypogaeic ant from Greece (Hymenoptera Formicidae). Bollettino della Societa Entomologica Italiana, 130, 177 - 182.","Mayr, G. (1868) Die Ameisen des baltischen Bernsteins. Beitrage zur Naturkunde Preussens, 1, 1 - 102.","Dlussky, G. M. (2011) The ants of the genus Lasius (hymenoptera, Formicidae) from late Eocene European ambers. Vestnik Zoologii, 45, 209 - 222."]}

Tribe Lasiini Ashmead, 1905 (Figs 6, 7, 8A���K, 9A���J, 10A���D) Type genus. Lasius. Included genus groups. Cladomyrma, Lasius group, Metalasius, Prenolepis group. Definition (worker). 1. With characters of Formicinae (see Bolton, 2003 and Note 1). 2. Mandible triangular, with 4���11 teeth; third tooth from apex reduced. 3. Dorsal mandibular groove, when present, running along lateral mandibular margin as seen in dorsal view (Note 2). 4. Palp formula usually 6,4, less often 3,4. 5. Frontal protuberance mediad antennal toruli with frontal carinae effaced, becoming broadly rounded posteriorly until continuous with face (Note 3). 6. Frontal protuberance raised above toruli or not. 7. Antennal toruli near or abutting posterior clypeal margin. 8. Antenna 12-, 11-, or 8-merous. 9. Compound eyes not enormous, that is, not longer than half the length of the head; eyes may be reduced to absent; long axis of eyes subparallel. 10. Ocelli present or absent (Note 4). 11. Metanotum differentiated or not. 12. Metapleural gland present, dorsal rim of metapleural gland curved inward. 13. Propodeal spiracle at or near posterolateral margin of propodeum. 14. Propodeal spiracle circular to elliptical, not slit-shaped. 15. Metacoxae wideset: Distance between mesocoxal bases less than between that between bases of metacoxae with mesosoma in ventral view and coxae oriented at right-angles to long axis of body. 16. Metatibiae without double row of ventral (inner) setae. 17. Petiolar foramen inprofile view low, not to barelyexceeding dorsal margin of metapleural gland, with or without dorsal margin or lip, but lip, when present, inconspicuous (Note 5). 18. Petiolar foramen in ventral view long, anterior margin exceeding metacoxal cavities anteriorly. 19. Petiolar node conspicuously shorter than propodeum, not reaching dorsal surface of propodeum (Note 6). 20. Petiolar apodeme (situated anteriorly on tergum) contiguous or nearly contiguous with petiolar node (Note 7). 21. Petiolar sternum U-shaped in cross-section (Note 8). 22. Abdominal segment III transverse sulcus absent. 23. Base of abdominal segment III with or without complete tergosternal fusion lateral to helcium, free sclerites commencing distantly up segment or near helcium; tergum III overhanging petiole or not. 24. Proventriculus sepalous (Note 9). Notes on definition: Note 1. The generic composition of the Lasiini has recently been reassessed following Blaimer et al. (2015) and Ward et al. (2016). The tribal definition proposed here is thus revised relative to Bolton (2003). It includes new characters and recognizes that several former plagiolepidines belong in the Lasiini. Note 2. Previous studies have not focused attention on the dorsal mandibular groove. Here it was observed that the groove, as seen with the mandible in dorsal view, runs along the outer margin of the mandible toward the mandibular apex in the Myrmelachistini, Lasiini and most Melophorini. This contrasts with the state observed in the ���formicoform radiation��� (i.e., the clade that includes Camponotini, Formicini and Melophorini, along with the monotypic tribes Gesomyrmecini, Gigantiopini, Oecophyllini, and Santschiellini; see the section ��� Kyromyrma, an ancestral formicine, under the section ��� Incertae sedis in the Formicinae��� below). When the groove is present in the ���formicoform radiation���, it is very close to the basal mandibular margin and is shortened, except in various plagiolepidines. The medial and shortened state may have arisen multiple times in the Formicini, Plagiolepidini, and Camponotini clade. Note 3. The ���frontal protuberance��� is the region between the antennal toruli, which is raised relative to the regions of the face laterad the toruli. To some degree, development of this condition accounts for the ���laterally directed��� torular condition of Formicidae (Boudinot et al., 2020). In other formicine tribes, including the Melophorini (with Prolasius as an exception), the frontal protuberance is carinate above the toruli (i. e., ���frontal carinae are present���), with these carinae continuing as a sharp ridge until their posterior terminus. Within the Lasiini, the frontal carinae are effaced; they are long in all groups except Cladomyrma, while in the Plagiolepidini the carinae are short in all genera except Anoplolepis. Note 4. Ocellus presence���absence is arelatively weak character as expression of ocelli may be variable for genera in which ocelli are observed, such as Lasius and Nylanderia. However, this statement is included as ocellus expression is a traditional character which is easy to evaluate and may have value for future works defining tribes wherein ocelli may be consistently present or absent. Within the Lasiini, ocelli are always absent in Cladomyrma, Euprenolepis Emery, and Pseudolasius Emery, variably present among Lasius, Paraparatrechina Donisthorpe, and Prenolepis Mayr species, and consistently present in Myrmecocystus, Paratrechina Motschoulsky (except P. kohli; see comments under Prenolepis genus group), and Zatania LaPolla et al. Note 5. The conformation of the dorsal region of the petiolar foramen is newly described here. There is complex variation of the form across the subfamily, but it appears at least that the form observed in the Lasiini is consistent; this form is also observed in the Myrmelachistini. In various lineages within the formicoform radiation, a raised and conspicuously carinate dorsal margin is observed. Note 6. Short petiolar nodes are also observed in the Myrmelachistini and Plagiolepidini (excluding Anoplolepis). The node height is variable in the Melophorini, being short in Prolasius and Myrmecorhynchus Andr��. Note 7. The apodeme is clearly separated from the node in most Melophorini, except Prolasius. Note 8. A U-shaped petiolar sternum was used by Bolton (2003) to diagnose the lasiine tribe group. This trait also occurs in the Myrmelachistini, Myrmoteratini Emery, Plagiolepidini, and four Melophorini (Lasiophanes, Prolasius, Stigmacros, Teratomyrmex); see ���Ancestral state estimation��� results above and Figure S15. Note 9. The proventriculus is weakly sepalous in Cladomyrma. The form of the proventriculus forms a natural division between the Plagiolepidini and the ���plagiolepidiform��� Prenolepis genus group, as observed by Emery (1925). Due to uncertainty about the polarity of the sepalous condition ��� and whether this form arose multiple times (Eisner, 1957; Agosti, 1990, 1991) ��� Bolton (2003) lumped the two plagiolepidiform clades, plus the Myrmelachistini, into the Plagiolepidini., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on pages 128-132, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Ashmead, W. H. (1905) A skeleton of a new arrangement of the families, subfamilies, tribes and genera of the ants, or the superfamily Formicoidea. The Canadian Entomologist, 37, 381 - 384.","Bolton, B. (2003) Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute, 71, 1 - 370.","Blaimer, B. B., Brady, S. G., Schultz, T. R., Lloyd, M. W., Fisher, B. L. & Ward, P. S. (2015) Phylogenomic methods outperform traditional multi-locus approaches in resolving deep evolutionary history: a case study of formicine ants. BMC Evolutionary Biology, 15, 257.","Ward, P. S., Blaimer, B. B. & Fisher, B. L. (2016) A revised phylogenetic classification of the ant subfamily Formicinae (Hymenoptera: Formicidae), with resurrection of the genera Colobopsis and Dinoponera. Zootaxa, 4072, 343 - 357. https: // doi. org / 10.11646 / Zootaxa. 4072.3.4.","Boudinot, B. E., Perrichot, V. & Chaul, J. C. M. (2020) † Camelosphecia gen. nov., lost ant-wasp intermediates from the mid-Cretaceous (Hymenoptera, Formicidae). ZooKeys, 1005, 21 - 55.","Emery, C. (1925) Hymenoptera. Fam. Formicidae. Subfam. Formicinae. Genera Insectorum, 183, 1 - 302.","Eisner, T. (1957) A comparative morphological study of the proventriculus of ants (Hymenoptera: Formicidae). Bulletin of the Museum of Comparative Zoology, 8, 439 - 490.","Agosti, D. (1990) What makes the Formicini the Formicini? Actes Colloques Insectes Sociaux, 6, 295 - 303.","Agosti, D. (1991) Revision of the oriental ant genus Cladomyrma, with an outline of the higher classification of the Formicinae (Hymenoptera: Formicidae). Systematic Entomology, 16, 293 - 310."]}

Species ��� Metalasius pumilus (Mayr, 1868) comb.nov. Definition (worker). 1. With character states of Metalasius (Note 1). 2. Maxillary palps long, reaching occipital foramen (Note 2). 3. Compound eyes well-developed, with > 20 ommatidia. 4. Mesosomal dorsum devoid of setae. 5. Legs entirely devoid of standing setae. 6. Petiolar node weakly inclined anteriorly, node squamiform. Notes on definition: Note 1. Several characters could not be evaluated for ��� M. pumilus, including the ventromedial mandibular groove, palpomere proportions, clypeal profile, and lateral hypostomal carina. Note 2. From Dlussky (2011). Comments. We place ��� M. pumilus and M. myrmidon together based on the results of our phylogenetic analyses, and we interpret presence of the broad third antennomere and highly reduced cranial setation as synapomorphies of this clade. ��� Metalasius pumilus differs from M. myrmidon by the following: (i) compound eyes large; (ii) maxillary palps long, reaching occipital foramen, and (iii) standing setae completely absent from head dorsum and mesosoma. Although, we have not examined the neotype of ��� M. pumilus, designated by Dlussky (2011) and deposited in Muzeum Ziemi Polskiej Akademii Nauk in Warsaw, the specimen we have studied is unlikely to be misidentified as it exhibits unique diagnostic traits of the species among the Lasiini, let alone of the Baltic amber fauna, including absence of setae on the head dorsum, well-developed eyes, short and broad third antennomere, and very small body size (< 2 mm). Dlussky (2011) describes the eyes of both ��� L. schiefferdeckeri and ��� M. pumilus as ���shifted somewhat posteriorly so that the length of [the] gena [is] more than [that of the] maximum diameter of [the] eyes���. This very general statement is true of both species, however, the eyes of ��� L. schiefferdeckeri are distinctly set in the posterior head half whereas those of ��� M. pumilus and M. myrmidon are situated at head midlength, distinguishing them from all Lasius genus group members., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on page 141, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Mayr, G. (1868) Die Ameisen des baltischen Bernsteins. Beitrage zur Naturkunde Preussens, 1, 1 - 102.","Dlussky, G. M. (2011) The ants of the genus Lasius (hymenoptera, Formicidae) from late Eocene European ambers. Vestnik Zoologii, 45, 209 - 222."]}

Genus ��� Sussudio gen.nov. Type and included species. ��� P. boreus Wheeler, 1915. Original designation. ZooBank LSID. http://zoobank.org/urn:lsid:zoobank.org:act: BFF515E7-9966-443F-8A34-555A4B41906B Definition (worker). 1. With characters of the Formicinae (Note 1). 2. Cranium size variable, width somewhat broader than to about twice that of mesosoma (Note 2). 3. Mandible triangular, with 7���8 teeth. 4. Dorsal mandibular groove extending along lateral mandibular margin in dorsal view. 5. Palps reduced, not reaching midlength of postgenal bridge. 6. Frontal carinae raised above antennal toruli. 7. Antennal toruli abutting posterior clypeal margin. 8. Antennomere count unknown (Note 3). 9. Antennomere III longer than broad. 10. Compound eyes situated posterior to head midlength. 11. Compound eyes not enormous and long axes subparallel. 12. Ocelli minutely present or absent. 13. Promesonotum domed, raised well above propodeum. 14. Metanotal groove well-developed. 15. Petiolar foramen in profile view clearly raised and margined with conspicuous thickened carina or lip. 16. Petiolar node squamiform, tall; dorsoventral height equal to or possibly exceeding dorsum of propodeum. 17. Abdominal segment III without raised tergosternal fusion. Notes on definition: Note 1. Several characters were not possible to evaluate. These include the following: Reduction of third tooth from mandibular apex, palp formula, the metapleural gland, ventral length of the petiolar foramen, relative separation of the meso- and metacoxae, presence or absence of setal double-row on ventral tibial surfaces, petiolar apodeme conformation, cross-sectional shape of the petiolar sternum, and presence or absence of the posthelcial sulcus. Note 2. The massive head of ��� P. boreus led Wheeler (1915) to erroneously assume that the specimens were majors of Pseudolasius; Wheeler did note the posteriorly set eyes of ��� P. boreus, one of the distinctions between it and Pseudolasius, but vacillated based on the insufficient knowledge of the latter genus at that time. Note 3. The examined specimens are missing their terminal antennomeres, and no previous descriptions of ��� P. boreus include an antennomere count. Etymology. Asimplification of ���pseudo- Pseudolasius ��� inspired by the musician Phil Collins. Masculine. Comments. ��� Sussudio boreus comb.nov. was previously placed in the Lasiini (Emery, 1925, Dlussky & Fedoseeva 1988, Bolton, 1994), and has been considered to be a member of the genus Pseudolasius (Wheeler, 1915; LaPolla & Dlussky, 2010). Based on an examination of a syntype (GZG-BST04646) and a nontype (NHMW1984-31-211) worker, as well as the original description from Wheeler (1915), we reject both placements. Neither specimen can be mistaken due to the unique combination of characters they display, including setation, high petiolar nodes, massive crania, and mesosomal form. ��� Sussudio boreus does not display the modifications of the third abdominal segment characteristic of the Prenolepis genus group, also rejecting its original placement in Pseudolasius (see diagnostic Note 2 above). ��� Sussudio is excluded from the Lasiini overall by two additional characters: (i) The petiolar node, which is completely vertical and very tall dorsoventrally, is as tall as or possibly taller than the propodeum; and (ii) the raised and conspicuously lipped petiolar foramen. No lasiine, extant or extinct, has such a tall petiolar node, nor do any species display the petiolar foramen conformation observed in ��� Sussudio. We cannot confidently place ��� Sussudio in any extant tribe, therefore, we consider ��� Sussudio incertae sedis in the Formicinae. As with other fossil taxa, which are of uncertain placement in the Formicinae, micro-CT scanning could be used to evaluate the form of the helcium and third abdominal sternum., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on pages 142-143, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Wheeler, W. M. (1915 1914) The ants of the Baltic Amber. Schriften der Physikalisch-Okonomischen Gesellschaft zu Konigsberg, 55, 1 - 142.","Emery, C. (1925) Hymenoptera. Fam. Formicidae. Subfam. Formicinae. Genera Insectorum, 183, 1 - 302.","Dlussky, G. M. & Fedoseeva, E. B. (1988) Origin and early stages of evolution in ants [in Russian]. Pp. 70 - 144 in: Ponomarenko, A. G. (ed.) Cretaceous Biocenotic Crisis and Insect Evolution. [in Russian.]. Moskva: Nauka, 232 pp.","Bolton, B. (1994) Identification Guide to the Ant Genera of the World, p. 222. Harvard University Press, Cambridge.","LaPolla, J. S. & Dlussky, G. M. (2010) Review of fossil Prenolepis genus-group species (Hymenoptera: Formicidae). Proceedings of the Entomological Society of Washington, 112, 258 - 273."]}

Species Metalasius myrmidon (Mei, 1998) comb.nov. Definition (worker). 1. With character states of Metalasius. 2. Dorsal mandibular groove absent (Note 1). 3. Ventromedial base of mandible without trough or impression (Note 2). 4. Maxillary palps short, exceeding hypostomal margin but not reaching postgenal bridge midlength. 5. Maxillary palpomere 3 longest, 4 shorter but as long as 5 and 6 together (Note 3). 6. Clypeus, in lateral view, convex and weakly bulging anteriorly (Note 3). 7. Anterior tentorial pit situated lateral to midlength of the epistomal suture. 8. Lateral hypostomal carina absent (Note 4). 9. Compound eyes absent, reduced or vestigial, with at most 9 ommatidia (Note 5). 10. Propodeal spiracle situated distinctly in lower half of propodeum (Note 6). 11. Legs almost entirely devoid of standing setae (Note 3). 12. Petiolar node weakly inclined anteriorly, node well-developed, squamiform (Note 7). Notes on definition: Note 1. The dorsal mandibular groove is discernable in all examined Lasius and Prenolepis genus group taxa. Note 2. Presence of a trough on the ventromedial base of the mandible is a newly detected synapomorphy of the core Prenolepis genus group. The impression is enhanced when the ventromedial mandibular margin is carinate and/or produced medially, and best seen when the mandibles are open and with the head in lateral anteroventral view. The trough may be reduced or absent in some species. Note 3. Previously included in the original diagnosis of the species M. myrmidon by Mei (1998). Note 4. The lateral hypostoma is usually delimited by a carina, which is discontinuous with the medial hypostomal lamina. Among formicines, the lateral hypostomal carina is absent only in Acropyga (some species) and Brachymyrmex, both genera outside of Lasiini. Note 5. The specimens, which were available for examination had 5���8 ommatidia; the maximum ommatidium count is from Mei (1998, p. 178). Note 6. Alowered propodeal spiracle appears sporadically replicated in only a few Prenolepis genus group members. Note 7. The petiolar node is strongly inclined anteriorly in the core Prenolepis genus group. Comments. Metalasius myrmidon is uniquely identified among the Lasiini by absence of the dorsal mandibular groove and lateral hypostomal carina, short and broad third antennomere, mid-set compound eyes (when present), which are reduced to at most 9 ommatidia and near complete absence of standing setae on the head. High magnification may be required to evaluate the lateral hypostoma., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on page 141, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Mei, M. (1998) Lasius (Cautolasius) myrmidon n. sp.: a new hypogaeic ant from Greece (Hymenoptera Formicidae). Bollettino della Societa Entomologica Italiana, 130, 177 - 182."]}

Genus Lasius Fabricius, 1804 = Donisthorpea Morice and Durrant, 1915. = Acanthomyops Mayr, 1862 syn.rev. = Austrolasius Faber, 1967 syn.nov. = Cautolasius Wilson, 1955 syn.nov. = Chthonolasius Ruzsky, 1912 syn.nov. = Dendrolasius Ruzsky, 1912 syn.nov. Type species. Formica nigra Linnaeus, 1758 (= L. niger). Subgeneric classification remarks. The modern body of taxonomic work on Lasius was initiated by Wilson���s revision of the genus (Wilson, 1955), which was classified into four subgenera at the time: Cautolasius, Chthonolasius, Dendrolasius, and Lasius s. str. In this work, Wilson provided a phylogeny of Lasius (Fig. 1A), but this treatment was an intuitive account of what he considered trends in the evolution of the morphology and biogeography of the genus. Subsequently, the subgenus Austrolasius was erected for a few socially parasitic species (Faber, 1967), andthe former genus Acanthomyops was included in Lasius as the sixth subgenus (Ward, 2005). The first phylogenetic inference based on molecular data was presented by Hasegawa (1998), who used COI to investigate relationships of four Lasius species (phylogeny not figured here). Since then, two major attempts at resolving the phylogeny were presented by Janda et al. (2004) and Maruyama et al. (2008) (Fig. 1B, C). Both studies used a combination of morphological characters and molecular data, including mitochondrial markers (COI, COII, tRNA-Leu, 16S). Amore recent effort focused on the phylogeny of European species related to L. niger (Lasius s. str.) and included nuclear genes LW Rh and wg in addition to 16S and COI (Talavera et al., 2015). To date, the monophyly of the subgenera has not been questioned except for the nominotypical subgenus (Janda etal., 2004; Maruyama etal., 2008). Recently, Seifert (2020, p. 21) stated that there is clear justification for elevating the subgenera to generic status. Such an action would considerably complicate the classification of the Lasius genus group because of the robustly supported paraphyly of the subgenera that we have uncovered here (Figs 1D, 2, S 1, Table 4). Specifically, in order to retain monophyly at the genus rank, four new genera would need to be erected for the species groups of brunneus, nearcticus, atopus, and pallitarsis. An additional issue would be the placement of the species which have not been sequenced, particularly those of the niger species group and, for example, the recently described L. brevipalpus Seifert, which is incertae sedis in the niger clade. The strongest morphological reorganization at the generic or subgeneric levels would be to recognize the reciprocally monophyletic niger and flavus clades as Lasius and Acanthomyops, respectively, but we refrain from doing so here (for our rationale, see ���Species group classification of Lasius ��� below). Comments on extant species. We determine that one species, Lasius escamole Reza should be excluded from Lasius and considered a junior synonym of the dolichoderine Liometopum apiculatum Mayr syn.nov. Reza (1925) described L. escamole in the context of a cultural study on the eponymous traditional Mexican dish known tobe made from the larvae of L. apiculatum (Hoey-Chamberlain et al., 2013). Although Reza���s description and illustrations are extremely vague, it is possible to see details that point to a dolichoderine identity. In the figures of the original description, the mandibles have long masticatory margin and small, sharp, even denticles, the ventral metasoma is shown as a slit-like anal opening rather than a formicine-like acidopore, and various figures display the fine, dense, appressed pilosity characteristic of Liometopum Mayr, but no erect setae as expected for Lasius. Many species have been added to Lasius since Wilson���s revision, mostly in Europe and Mediterranean, while North American taxa have largely remained untreated except for a thorough revision of Acanthomyops (Wing, 1968a, 1968b). Careful research has revealed multiple Palaearctic Lasius species that show only subtle morphological differentiation from close relatives (Seifert, 1983, 1990, 1991, 1992, 2020; Schlick-Steiner et al., 2003). There is no reason to believe that North America does not harbour a diverse fauna of such ���cryptic species���. For example, the question of the putative Holarctically distributed Lasius species was resolved by Sch��r et al. (2018) who elevated to species rank the American representatives of L. alienus, L. flavus, and L. umbratus Nylander, recognizing the following revived taxa, in order: L. americanus Emery, L. brevicornis Emery, and L. aphidicola (Walsh). Renewed focus on the Nearctic fauna is necessary, as is expanded sequencing at the global scale. Comments on extinct species. Without having scored the Baltic Lasius fossils other than ��� L. schiefferdeckeri, that is, ��� L. punctulatus Mayr and ��� L. nemorivagus Wheeler, we are unable to quantitatively address their placement. Historically, ��� L. punctulatus and ��� L. schiefferdeckeri were considered to be members of Lasius s. str. (Wilson, 1955; Dlussky, 2011), while the queen-based ��� L. nemorivagus was placed in Chthonolasius (Wilson, 1955) later to be implicitly considered incertae sedis in the genus (Dlussky, 2011). Our combined-evidence dating analyses recover ��� L. schiefferdeckeri as sister to or within the Lasius genus group (Figs 4, S 7���S 9). As the specific relationship of the fossil to the extant species of the Lasius genus group is uncertain, we conservatively consider the fossil incertae sedis in Lasius. There remains the possibility that ��� L. schiefferdeckeri is ancestral to the extant niger clade and is indicative of low rates of phenotypic transformation, as suggested by Mayr (1868), Wheeler (1915), and Wilson (1955). The placement of ��� L. schiefferdeckeri may be refined in future study by scoring characters which are explicitly derived from comparison of the brunneus and niger groups within the niger clade. The two differentiating traits proposed for the brunneus and niger groups are, on average, < 8 mandibular teeth in the brunneus group (Seifert, 1992; some niger group species with < 8), and presence of a subapical cleft in the mandibles of brunneus group males (Wilson, 1955). While ��� L. schiefferdeckeri demonstrates both a tooth count of < 8, and presence of a subapical cleft, the latter character is probably plesiomorphic of the Lasius genus group, and the polarity of the former is uncertain. Notably, Wilson (1955) observed that the male mandibles of ��� L. schiefferdeckeri are observed to vary from the ��� brunneus form��� to the derived ��� niger form���. With these three traits in mind, it does seem reasonable that ��� L. schiefferdeckeri is stem to or directly ancestral to the niger clade. Note on biology. Despite the interest in this genus, however, basic natural history remains unknown for many species, including the morphologically aberrant L. atopus and the species we sequence here, ��� L. nr. atopus ���. Only a handful of recently published studies have addressed the behaviour of some of the more rarely encountered species (e.g., Raczkowski & Luque, 2011), indicating that more effort is needed to elucidate the biology of Lasius., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on pages 135-136, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Fabricius, J. C. (1804) Systema Piezatorum Secundum Ordines, Genera, Species, Adjectis Synonymis, Locis, Observationibus, Descriptionibus. Brunswick: C. Reichard. xiv + 15 - 439 + 30 pp.","Faber, W. (1967) Beitrage zur Kenntnis sozialparasitischer Ameisen. I. Lasius (Austrolasius n. sg.) reginae n. sp., eine neue temporar sozialparasitische Erdameise aus Osterreich (Hym. Formicidae). Pflanzenschultz Berichte, 36, 73 - 107.","Wilson, E. O. (1955) A monographic revision of the ant genus Lasius. Bulletin of the Museum of Comparative Zoology, 113, 1 - 201.","Linnaeus, C. (1758) Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata. Holmiae [= Stockholm]: L. Salvii, 824 pp.","Ward, P. S. (2005) A synoptic review of the ants of California (Hymenoptera: Formicidae). Zootaxa, 936, 1 - 68.","Hasegawa, E. (1998) Phylogeny and host-parasite relationships in social parasitism in Lasius ants. Entomological Science, 1, 133 - 135.","Janda, M., Folkova, D. & Zrzavy, J. (2004) Phylogeny of Lasius ants based on mitochondrial DNA and morphology, and the evolution of social parasitism in the Lasiini (Hymenoptera: Formicidae). Molecular Phylogenetics and Evolution, 33, 595 - 614.","Maruyama, M., Steiner, F. M., Stauffer, C., Akino, T., Crozier, R. H. & Schlick-Steiner, B. C. (2008) A DNA and morphology based phylogenetic framework of the ant genus Lasius with hypotheses for the evolution of social parasitism and fungiculture. BMC Evolutionary Biology, 8, 1 - 15. Article 237. https: // doi. org / 10.1186 / 1471 - 2148 - 8 - 237.","Talavera, G., Espadaler, X. & Vila, R. (2015 2014) Discovered just before extinction? The first endemic ant from the Balearic Islands (Lasius balearicus sp. nov.) is endangered by climate change. Journal of Biogeography, 42, 589 - 601. https: // doi. org / 10.1111 / jbi. 12438.","Seifert, B. (2020) A taxonomic revision of the Palaearctic members of the subgenus Lasius s. str. (Hymenoptera, Formicidae). Soil Organisms, 92, 15 - 86.","Reza, A. (1925) Recursos alimenticios de Mexico de origen animal poco conocidos. Memorias y Revista de la Sociedad Cientifica \" Antonio Alzate \", 44, 1 - 22.","Hoey-Chamberlain, R., Rust, M. K. & Klotz, J. H. (2013) A review of the biology, ecology and behavior of velvety tree ants of North America. Sociobiology, 60, 1 - 10.","Wing, M. W. (1968 a) Taxonomic revision of the Nearctic genus Acanthomyops (Hymenoptera: Formicidae). Memoirs of the Cornell University Agricultural Experiment Station, 405, 1 - 173.","Wing, M. W. (1968 b) A taxonomic revision of the Nearctic genus Acanthomyops Mayr (Hymenoptera: Formicidae). [Abstract.]. Dissertation Abstracts. B. Sciences and Engineering, 28, 3934.","Seifert, B. (1983) The taxonomical and ecological status of Lasius myops Forel (Hymenoptera, Formicidae) and first description of its males. Abhandlungen und Berichte des Naturkundemuseums Gorlitz, 57, 1 - 16.","Seifert, B. (1990) Supplementation to the revision of European species of the ant subgenus Chthonolasius Ruzsky, 1913 (Hymenoptera, Formicidae). Doriana, Supplemento agli Annali del Museo Civico di Storia Naturale \" G. Doria \". GEN, 6, 1 - 13.","Seifert, B. (1991) Lasius platythorax n. sp., a widespread sibling species of Lasius niger (Hymenoptera: Formicidae). Entomologia Generalis, 16, 69 - 81.","Seifert, B. (1992) A taxonomic revision of the Palaearctic members of the ant subgenus Lasius s. str. (Hymenoptera: Formicidae). Abhandlungen und Berichte des Naturkundemuseums Gorlitz, 66, 1 - 67.","Schlick-Steiner, B. C., Steiner, F. M., Schodl, S. & Seifert, B. (2003) Lasius austriacus sp. n., a central European ant related to the invasive species Lasius neglectus. Sociobiology, 41, 725 - 736.","Schar, S., Talavera, G., Espadaler, X., Rana, J. D., Anderson, A. A., Cover, S. P. & Vila, R. (2018) Do Holarctic ant species exist? Trans-Beringian dispersal and homoplasy in the Formicidae. Journal of Biogeography, 45, 1 - 12. https: // doi. org / 10.1111 / jbi. 13380.","Dlussky, G. M. (2011) The ants of the genus Lasius (hymenoptera, Formicidae) from late Eocene European ambers. Vestnik Zoologii, 45, 209 - 222.","Mayr, G. (1868) Die Ameisen des baltischen Bernsteins. Beitrage zur Naturkunde Preussens, 1, 1 - 102.","Wheeler, W. M. (1915 1914) The ants of the Baltic Amber. Schriften der Physikalisch-Okonomischen Gesellschaft zu Konigsberg, 55, 1 - 142.","Raczkowski, J. M. & Luque, G. M. (2011) Colony founding and social parasitism in Lasius (Acanthomyops). Insectes Sociaux, 58, 237 - 244."]}

On the identity of ��� Protrechina Wilson: Wilson (1985) described a genus putatively close to Paratrechina sensu lato (��� Prenolepis genus group) from mid-Eocene Claiborne amber (Arkansas, 40.4���37.2 Ma; Saunders et al., 1974). This genus, ��� Protrechina, supposedly differs from Paratrechina s. l., Lepisiota Santschi and Brachymyrmex Mayr ��� among other, unstated formicines ��� by the absence of standing macrosetae on the mesosomal dorsum, a state similar to that observed for Metalasius gen.nov. as noted below. The genus has been variably treated as a lasiine (Bolton, 1994, 1995; LaPolla & Dlussky, 2010), a ���prenolepidine��� (H��lldobler & Wilson, 1990), or as incertae sedis in the subfamily where it remains at present (Wilson, 1985; Dlussky & Fedoseeva 1988; Bolton, 2003; Ward et al., 2016). The type specimen of ��� Protrechina carpenteri Wilson, at the Museum of Comparative Zoology (Harvard), should be reexamined to evaluate its tribal, and perhaps generic, placement. This would be particularly valuable given the approximately mid-Eocene origin of the Prenolepis genus group here inferred (Fig. 4; Table 5); such a study will be facilitated by use of micro-CT (e.g., Hita-Garcia et al., 2017; Barden et al., 2017b; Boudinot et al., in press), given the poor condition of the specimen reported by LaPolla & Dlussky (2010)., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on page 133, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Wilson, E. O. (1985) Ants from the Cretaceous and Eocene amber of North America. Psyche, 92, 205 - 216.","Saunders, W. B., Mapes, R. H., Carpenter, F. M. & Elsik, W. C. (1974) Fossiliferous amber from the Eocene (Claiborne) of the Gulf coastal plain. GSA Bulletin, 85, 979 - 984.","Bolton, B. (1994) Identification Guide to the Ant Genera of the World, p. 222. Harvard University Press, Cambridge.","Bolton, B. (1995) A New General Catalogue of the Ants of the World, p. 504. Harvard University Press, Cambridge.","LaPolla, J. S. & Dlussky, G. M. (2010) Review of fossil Prenolepis genus-group species (Hymenoptera: Formicidae). Proceedings of the Entomological Society of Washington, 112, 258 - 273.","Holldobler, B. & Wilson, E. O. (1990) The Ants. Harvard University Press, Cambridge, Massachusetts. xii + 732 pp.","Dlussky, G. M. & Fedoseeva, E. B. (1988) Origin and early stages of evolution in ants [in Russian]. Pp. 70 - 144 in: Ponomarenko, A. G. (ed.) Cretaceous Biocenotic Crisis and Insect Evolution. [in Russian.]. Moskva: Nauka, 232 pp.","Bolton, B. (2003) Synopsis and classification of Formicidae. Memoirs of the American Entomological Institute, 71, 1 - 370.","Ward, P. S., Blaimer, B. B. & Fisher, B. L. (2016) A revised phylogenetic classification of the ant subfamily Formicinae (Hymenoptera: Formicidae), with resurrection of the genera Colobopsis and Dinoponera. Zootaxa, 4072, 343 - 357. https: // doi. org / 10.11646 / Zootaxa. 4072.3.4.","Hita-Garcia, F., Fischer, G., Liu, C., Audisio, T. L. & Economo, E. P. (2017) Next-generation morphological character discovery and evaluation: an X-ray micro-CT enhanced revision of the ant genus Zasphinctus Wheeler (Hymenoptera: Formicidae: Dorylinae) in the Afrotropics. ZooKeys, 693, 33 - 93.","Barden, P., Herhold, H. W. & Grimaldi, D. A. (2017 b) A new genus of hell ants from the Cretaceous (Hymenoptera: Formicidae: Haidomyrmecini) with a novel head structure. Systematic Entomology, 42, 837 - 846."]}

Exclusion of ��� Glaphyromyrmex from the Lasiini: The Baltic amber formicine, ��� Glaphyromyrmex Wheeler, was placed in the Formicini until recently (Wheeler, 1915, Donisthorpe, 1943, Dlussky, 1967, Dlussky & Fedoseeva 1988, Bolton, 1994), when Dlussky (2008) transferred the genus to the Lasiini. Placement of ��� Glaphyromyrmex in the Lasiini is counterintuitive given presence of a ventral double-row of setae on its metatibiae, a state which does not occur in any lasiine. Intuitive placement of ��� Glaphyromyrmex based on morphology is challenging, however. ��� Glaphyromyrmex differs from members of all formicine tribes in which double seta rows occur (Formicini, Camponotini, some Melophorini). Specifically, ��� Glaphyromyrmex differs from the Formicini and most Camponotini in eye position (eyes set at about head midlength), from the Camponotini in having antennal toruli which abut the posterior clypeal margin (vs widely separated), and from the Melophorini, which have well-defined dorsal and ventral flaps surrounding the metapleural gland, a conformation that is apparently absent in ��� Glaphyromyrmex. Recognizing these differences, however, we transfer ��� Glaphyromyrmex back to the Formicini (tribal transfer) based on our combined analyses (Fig. 4) and recommend revised study of the fine-scale external anatomy of the fossil taxon., Published as part of Boudinot, Brendon E., Borowiec, Marek L. & Prebus, Matthew M., 2022, Phylogeny, evolution, and classification of the ant genus Lasius, the tribe Lasiini and the subfamily Formicinae (Hymenoptera: Formicidae), pp. 113-151 in Systematic Entomology 47 on page 132, DOI: 10.1111/syen.12522, http://zenodo.org/record/5975346, {"references":["Wheeler, W. M. (1915 1914) The ants of the Baltic Amber. Schriften der Physikalisch-Okonomischen Gesellschaft zu Konigsberg, 55, 1 - 142.","Donisthorpe, H. (1943) A list of the type-species of the genera and subgenera of the Formicidae. [part]. Annals and Magazine of Natural History, 10, 617 - 688.","Dlussky, G. M. (1967) Ants of the genus Formica from the Baltic Amber. Paleontological Journal, 1, 69 - 77.","Dlussky, G. M. & Fedoseeva, E. B. (1988) Origin and early stages of evolution in ants [in Russian]. Pp. 70 - 144 in: Ponomarenko, A. G. (ed.) Cretaceous Biocenotic Crisis and Insect Evolution. [in Russian.]. Moskva: Nauka, 232 pp.","Bolton, B. (1994) Identification Guide to the Ant Genera of the World, p. 222. Harvard University Press, Cambridge.","Dlussky, G. M. (2008) Ants of the tribe Formicini (hymenoptera, Formicidae) from late Eocene amber of Europe. Paleontological Journal, 42, 500 - 513."]}

The hypogaeic ant subfamilies Leptanillinae and Martialinae likely form the sister group to the remainder of the extant Formicidae. In order to increase the knowledge of anatomy and functional morphology of these unusual and phylogenetically crucial ants, we document and describe in detail the cranium of a leptanilline, Protanilla lini Terayama, 2009. The mandibular articulation of the species differs greatly from that of other ants studied so far, and clearly represents a derived condition. We propose a mode of movement for the specialized mandibles that involves variable rotation and sophisticated locking mechanisms. While a wide opening gape and a unique articulation are characteristics of the mandibular movement of P. lini, the observed condition differs from the trap-jaw mechanisms occurring in other groups of ants, and we cannot, at present, confirm such a functional configuration. Protanilla lini displays hardly any plesiomorphies relative to the poneroformicine ants, with the possible exception of the absence of the torular apodeme. Instead, the species is characterized by a suite of apomorphic features related to its hypogaeic and specialized predatory lifestyle. This includes the loss of eyes and optic neuropils, a pronouncedly prognathous head, and the derived mandibular articulation. The present study is an additional stepping-stone on our way to reconstructing the cephalic ground plan of ants and will contribute to our understanding of ant evolution.

Tardigrades are a diverse group of charismatic microscopic invertebrates that are best known for their ability to survive extreme conditions. Despite their long evolutionary history and global distribution in both aquatic and terrestrial environments, the tardigrade fossil record is exceedingly sparse. Molecular clocks estimate that tardigrades diverged from other panarthropod lineages before the Cambrian, but only two definitive crown-group representatives have been described to date, both from Cretaceous fossil deposits in North America. Here, we report a third fossil tardigrade from Miocene age Dominican amber. Paradoryphoribius chronocaribbeus gen. et sp. nov. is the first unambiguous fossil representative of the diverse superfamily Isohypsibioidea, as well as the first tardigrade fossil described from the Cenozoic. We propose that the patchy tardigrade fossil record can be explained by the preferential preservation of these microinvertebrates as amber inclusions, coupled with the scarcity of fossiliferous amber deposits before the Cretaceous.

Tardigrades are a diverse group of charismatic microscopic invertebrates that are best known for their ability to survive extreme conditions. Despite their long evolutionary history and global distribution in both aquatic and terrestrial environments, the tardigrade fossil record is exceedingly sparse. Molecular clocks estimate that tardigrades diverged from other panarthropod lineages before the Cambrian, but only two definitive crown-group representatives have been described to date, both from Cretaceous fossil deposits in North America. Here, we report a third fossil tardigrade from Miocene age Dominican amber. Paradoryphoribius chronocaribbeus gen. et sp. nov. is the first unambiguous fossil representative of the diverse superfamily Isohypsibioidea, as well as the first tardigrade fossil described from the Cenozoic. We propose that the patchy tardigrade fossil record can be explained by the preferential preservation of these microinvertebrates as amber inclusions, coupled with the scarcity of fossiliferous amber deposits before the Cretaceous.

List of characters and character states used in the phylogenetic analyses