Camelosphecia fossor, Boudinot & Perrichot & Chaul, 2020

Boudinot, Brendon E., Perrichot, Vincent & Chaul, Julio C. M., 2020, † Camelosphecia gen. nov., lost ant-wasp intermediates from the mid-Cretaceous (Hymenoptera, Formicoidea), ZooKeys 1005, pp. 21-55 : 21

† Camelosphecia fossor sp. nov. Figs 1A , 2A , 13 , 14 , 15

Holotype.

Myanmar, Kachin State: Hukawng Valley [ANTWEB1038930, deposited in DZUP].

Additional material examined.

Same as holotype [females: BALBuTJ-36, BALBuTJ-38, BALBuTJ-40 all in Janovitz collection]

Diagnosis.

Recognizable as Formicoidea and † Camelosphecia as defined above. Distinguished from † C. venator by features listed in that species’ diagnosis. In briefest, the most distinct features include massive compound eyes, huge and muscular profemora, and presence of psammochaetae on the protarsus.

Measurements.

Female. CL 0.76; HL 0.94; WH 1.08; CW 0.46; EL 0.41; MW 0.07; LW 0.06; A1L 0.21; A2L 0.11; A3L 0.22; PnW 0.66; PL 0.83; PnLm 1.05; MtW 0.66; MtL 0.41; MsW 0.37; MsL 0.32; WL 1.83; PtL 0.63.

Description.

Female. Head. Postgenal bridge elongate, thus head “prognathous”. Head posterior to clypeus strongly broadened (broader than long) and inflated, except for a pair of concavities lying over the posterolateral clypeal margin which accommodate the base of scapes. Mandibles cup-shaped, strongly bowed. Masticatory margin of mandibles with 13 teeth. Teeth, except the apical, truncate, gear-like; individual teeth short basally on masticatory margin and gradually increasing in length apically. Apical tooth (maybe apical and preapical) largest, pointed. Ventral surface of mandible without dense tuft of chaetae. Mandibles crossing apically, at full closure approximately half the masticatory margin would cross. Basolateral area of dorsal mandibular surface just beneath malar margin distinctly concave, contrasting to the remaining strongly convex, dome-shaped surface; the margin of this area just before meeting the cranium sinuous in profile view, appearing dentate. Labrum bilobed, its dorsum covered with ca. 24 long, stout chaetae with gently curved tips (chaetae somewhat shorter than 0.1 mm). Palps basally concealed by the labrum and mandibles, so that maxillary palpomeres total count is five or six and labial palpomeres are not visible. Maxillary palpomeres elongate. Clypeus having a basal section integrated with the cranium and an anteromedially projected over mandibles as a thin laminar platform, its maximum width ca. 0.4 × that of head. Clypeal platform having a pair of broad and low anterolateral lobes which curve into an anteromedial pair of close-set triangular teeth. In face view, considering the entire clypeus, the anterior clypeal margin bears two pairs of lobes and the medial pair of teeth, the lobes laterad corresponding to the actual anterolateral corners of the clypeus. Posterior to the platform, the remainder of the clypeus is rightly integrated into the cranium and confined to the anterior eighth of the head. The posterior margin of the clypeus is poorly marked medially, between the toruli, the margin slightly surpassing toruli anteriormost level, but not reaching their posteriormost level.

Antennae. Torulus laterally directed; posteromedian portion of torular arch slightly enlarged and covering part of bulbus. Bulbus and bulbus neck coplanar and angled in relation to scape. Antennae 12-merous, not clubbed. Longest antennomeres are I (scape) and III, these two being subequal in length. Antennomere II (pedicel) is small and slightly inflated. Antennomere IV longer than V. Antennomeres V-XI more-or-less similar in size and shape. Apical antennomere not much longer than previous. Antennomeres dorsoventrally compressed (could be a taphonomic artifact). Frontal carinae absent. Eyes enormous, not bulging, length ca. 2 × the width in the full view of the eye; in full-face view, eye length ca. 0.7 × the length of head discounting clypeal projection. In full-face view, medial margin of compound eyes weakly concave, although not conspicuously notched. Ocelli relatively small and positioned high on dorsum of head, the lateral pair almost reaching the vertexal margin in full-face view. Vertexal margin slightly convex. Lateral margins almost entirely occupied by the compound eyes, except for anterior portions, which converge until meeting the outer margin of mandibles. Posterolateral and lateral occipital margin carinate, the margin poorly delimited posteromedially and anteromedially. Ventral surface of head flat to gently concave, with a slightly raised longitudinal median section corresponding in location with the postgenal ridge. Postgenal ridge with a small indentation at its posterior limit. Small, simple, suberect to recurved setae on dorsum of head, except for longer ones originating on the anterior edge of the clypeus and on the mandibles. Antennomeres II-XII covered on dense pubescence.

Mesosoma. Pronotum elongate, distinctly bell-shaped in dorsal view; posteriormost region transversely constricted. Pronotum without anterior fringe of setae which is observed in † Camelomecia ; anterior margin of pronotum, however, with distinct “beading” or rim and sulcus which delimit the anteriormost region. In profile view, posterodorsal portion extended posteriorly as a lobe, with the lobe situated very close to the tegula (nearly contacting); posterior margin just below lobe apparently concave; posteroventral margin lobate, not extending medially posterior to fore coxae, as would be expected for Apoidea . Mesonotum (mesoscutum + mesoscutellum) length in dorsal view subequal to length of pronotum. Mesoscutum> 1.5 × broader than long, more-or-less oval in shape. Axillae small. Scutoscutellar sulcus distinct and cross-ribbed, but not particularly deep. Mesoscutellum slightly longer than wide, tapering posterad and with an arched posterior margin. Mesopleuron bulging; oblique mesopleural sulcus present as a thin and poorly-marked line in the upper half of the mesopleural area posteriorly, separating the upper mesopleural area (erstwhile “anepisternum”) from the lower mesopleural area (erstwhile “katepisternum”); lower mesopleural area ca. 4 × longer than upper mesopleural area. Propodeal spiracle large, protruding from the cuticle, its opening slit and crescent-shaped and posteriorly oriented; spiracle positioned on the upper anterior region of the lateropropodeal surface. Lower metapleural area thin, delimited posteroventrally by carina. Upper metapleural area triangular, its margins approximately the same size. A small metanotal spiracle is apparently seen on the upper anterior corner of the left metapleural area. Propodeum with a subquadrate lamellate projection developed on the lower posterolateral mesosomal corner, projecting over the bases of the metacoxa and metasomal petiole. The anterior and posterior angles of the projection are sharply defined, and its dorsal surface is concave. Propodeum dorsal and declivous faces separated from the lateral face by a pair of ridges that are poorly marked anteriorly and strongly marked posteriorly, each reaching the metapleuropropodeal lamellate projection posteriorly; in the holotype, it appears that a pair of indentations on the upper portion of the propodeal ridges make the propodeum angled in profile view (at least on the left side of the specimen), whereas in the non-type specimens, these carinae toothed at the posterodorsal angle. Metapleural gland orifice absent, and there is no trace of a metapleural gland reservoir (bulla).

Legs. Procoxa and profemur hypertrophied. Protibia bearing distally next to calcar a short, robust, spike-shaped chaeta. Calcar thin, curved, with bifid tip, without a distinct brush along its length, but having pubescence-like projections. Probasitarsal notch only gently concave, bearing the probasitarsal comb, but without any chaetae next to it. Probasitarsus and protarsomere II forming a specialized structure consisting of long, curved, somewhat bluntly tipped, psammochaetae. Probasitarsus anterior surface having two of such specialized sensilla trichodea apically, projecting over protarsomere II and protarsomere II bearing three of such sensilla trichodea on its anterior surface. The five psammochaetae are very close together and probably form a digging apparatus in analogy to extant fossorial Aculeata . In addition to the specialized chaetae, a pair of spike-shaped chaetae is also present apically on the posterior surface of probasitarsus as well as a tiny, peg-like chaeta apicomedially on the posterior surface. Protarsomere II has additionally a pair of small, spike-shaped chaetae on its posterior apical edge and an apicomedian, enlarged, blister-like, lobate chaeta on the posterior surface. Protarsomere II is short and slightly offset from the long axis of the probasitarsus. Protarsomeres III and IV each bearing two pairs of small, spike-shaped chaetae apicolaterally and with a lobate apicomedial chaeta in between them on the posterior surface, similar in shape but not as enlarged as that on protarsomere II. Spike-shaped chaetae and lobate chaeta apparently absent on protarsomere V. Pretarsal claws of proleg robust and curved, armed with a pair of teeth on their inner margins. Arolium slightly longer than half the length of claws. Mid and hind legs without any hypertrophied segment, although metatibiae apically clavate. Meso- and metatarsomeres I-IV similar in structure to protarsomeres III and IV, except for the apicomedian chaeta, which is not lobate and apparently rigid. These chaetae are also longer and more conspicuous on the mesotarsus than on the metatarsus. Paired mesotibial spurs present; spurs long and simple. Metatibial spurs not preserved, but from non-type material can be described as a pair of long and simple spurs similar but slightly longer than that on mesotibia.

Metasoma. In total, three metasomal segments of holotype preserved, corresponding to abdominal segments II-IV. Petiole (abdominal II) massive in dorsal view; posttergite II anteriorly broad (approximately as broad as the width at midlength of the mesoscutellum), broadly inserting into the lower propodeal declivous surface (propodeal foramen wide). Laterotergite of segment II well-defined and dorsoventrally broad. Posttergite II mildly constricted posteriorly and consequently, constriction between pre- and posttergite III also not strong, therefore, the abdominal segment II has only mild petiolation. Poststernite II V-shaped in ventral view, its lateral margins carinate (could be a taphonomic artifact), tapering anteriorly until meeting and forming a small subpetiolar process (in profile largely obliterated by the metacoxae). Entire posttergite II and anterior portion of posttergite III laterally carinated. Anterior process on poststernite III, the prora, subrectangular; its anterior angle round and the posterior angle pointy and inclined ventrally. Abdominal segment IV, as determined from non-type specimens, with slight constriction corresponding to transverse sulci which delimit the pre- and post-sclerites of the tergum and sternum; lateral margins of tergum and sternum IV aligned for their whole length. Sclerites of abdominal segments V, VI, and VII telescoped internally, their tergal margins apparently overlap the sterna laterally.

Wing venation. (Determined from non-type specimens.) Costal vein (C), subcostal-radial-radial-sector complex vein (Sc+R+Rs), and first free abscissa of the Radius (Rf1) present and tubular, enclosing costal cell. Pterostigma well-developed, situated near the apical third of the fore wing, but exact position difficult to ascertain. Rf distal to pterostigma present, meeting the free Radial Sector (Rsf) and enclosing third radial cell (3R1, or "first marginal cell", 1MC). Cell 3R1 ca. 4 × as long proximodistally as wide anteroposteriorly; apex of cell rounded and considerably distant from apex of wing. The first free abscissa of the Radial Sector (Rsf1) splitting from Sc+R+Rs proximal to the pterostigma, but separated by ca. 1 of its lengths; Rsf1 directed posterobasally. The mediocubital complex vein (M+Cu) present; free Media (Mf) and Cubitus (Cuf) splitting near midlength of wing. First free abscissa of Media (Mf1) short, with a length subequal to that of the first cubitoanal crossvein (1cu-a). Rsf1 and (Mf1) meeting at a very oblique angle, nearly parallel; Radial-Sector-Media composite abscissa (Rs+M) tubular, directed posterodistally, and nearly orthogonal to main axis of Rsf1 and Mf1; Rs+M length subequal to that of Rsf1; split of Rs and M distal to anterior juncture of first mediocubital crossvein (1m-cu), thus Rs+M comprising two abscissae (Rs+M1, Rs+M2), and 1m-cu “prefurcal” in general aculeate terminology. 1m-cu short, subequal in length to Mf1. Rsf immediately distal to split of Rs+M, with apex of kink marked by flexion line, thus Rsf2 and Rsf3 defined; flexion line spectral, thus first radiosectoral crossvein (1r-rs) “absent”. Second radiosectoral crossvein (2r-rs) tubular, situated at approximately pterostigma midlength, directed slightly posterodistally, and short (length subequal to Mf1, 1cu-a). Rsf distal to 2r-rs divided into two remaining abscissae (Rsf4, Rsf5) by second sectoriomedial crossvein (2rs-m) [note: 1rs-m always absent in Hymenoptera due to fusion of Rsf and Mf which forms Rs+M]; Rsf4 longer than 2r-rs but shorter than Rf1, 2rs-m. Mf, distal to Rs+M, straight and divided into two abscissae by 2rs-m (Mf2, Mf3); Mf2 longer than Rs+M but shorter than Rsf5; Mf3 tubular but becoming spectral well before apex of wing. Two "submarginal cells" enclosed by tubular abscissae; third "submarginal cell" undefined due to absence of third sectoriomedial crossvein (3rs-m). First medial cell (1M, or "discal cell 1") rhomboidal, ca. 4 × as long proximodistally as wide anteroposteriorly; Mf1 and 1m-cu parallel; Rs+M and first free cubital abscissa (Cuf1) parallel. Second medial cell (2M, or " discal cell 2 ") undefined due to absence of the second mediocubital crossvein (2m-cu). The second free cubital abscissa (Cuf2) evenly and shallowly curved until its apex is directed posteriorly; Cuf2 apparently reaching first anal vein (1A); cubitus distal to Cuf nebulous to spectral and curved. 1cu-a situated considerably proximad M+Cu split, being distant by at least twice its length, hence 1cu-a "very prefurcal". 1A tubular, although full extend uncertain. Hind wing venation not evaluated due to lack of appropriate preserved views.

Preservation. Holotype. The body parts of the holotype that have suffered considerable distortion inside the amber matrix are the left procoxa, left mesopleuron and left mesocoxa, left and right metapleura and metacoxae, and the propodeum. Propodeal and metathoracic regions are considerably distorted, so much so that it is impossible to determine on which side the morphology has been better preserved. For example, on the right side, the propodeal spiracle is positioned at the same level of the mesocoxa in an anteroposterior axis, and the distance between the spiracle and the metapleural posteroventral corner is 0.43 mm. On the left side, it is positioned slightly anterior to the mesocoxa level and the distance between it and the metapleural corner is 0.32 mm. Missing body parts are: left protarsus; left mesotibia and mesotarsus; left metafemur, metatibia, and metabasitarsus; part of the right mesofemur and mesotibia, right metafemur, metatibia and metatarsus; entire abdominal segments IV-VII and part of abdominal segments II and III.

Syninclusions. One nematoceran fly, which remains in the same amber piece with the holotype. Two staphylinid beetles, which were separated from the holotype in other amber pieces after the preparation (JCCamb00051 and JCCamb00052, both in JCMC).

Etymology.

The specific epithet emphasizes the digging adaptations of the species; the name is treated as a noun in apposition.

Comments. Four additional specimens of † Camelosphecia , three females (Fig. 15 ) and one male (Fig. 16 ), were studied based on images only. Among the females, two specimens (BALBuTJ_36 and BALBuTJ_40) are probably conspecifics to † C. fossor and one of them (BALBuTJ_38) probably represents another species. BALBuTJ_36 (Fig. 15A ) is particularly interesting for its exceptional preservation. No significant differences were found between † C. fossor holotype and BALBuTJ_36, and the fossil was used to complete the description of † C. fossor , as most of the metasoma of the holotype was missing and its propodeum very distorted. BALBuTJ_40 (Fig. 15C ) is a fossil difficult to interpret for containing a lot of debris and internal fractures around the inclusion. We doubtfully consider it conspecific to † C. fossor . A more thorough examination of the specimen can change this interpretation. BALBuTJ_38 almost certainly is a different species which we do not describe here. It differs from † C. fossor for having abundant thick, long and flexuous setae dorsally on mesosoma; unarmed, block-like propodeum; and an even thicker profemur.

Figures

Figure 1. Mandibles of representative Formicoidea A † Camelosphecia fossor gen. et sp. nov. holotype female, lateral oblique (ANTWEB 1038930) B † Gerontoformica species, male, dorsal or full-face view (ANTWEB 1032638) C † Chonidris insolita holotype female, anterolateral oblique (FANTWEB 00022, AntWeb: Vincent Perrichot).

Figure 2. Mouthparts of † Camelomecia clade genera A † Camelosphecia fossor gen. et sp. nov. holotype female, dorsolateral oblique (ANTWEB 1038930) B † Camelomecia janovitzi holotype female, anterolateral oblique (AMNH-BUTJ 003, AntWeb: Phil Barden).

Figure 13. Holotype of † Camelosphecia fossor sp. nov. A lateral view of right side of head B full face view of head, right margin blurred on this view due to a folding of the facet. Box on bottom right evidencing scape under fluorescent microscopy C detail of clypeus, mandibles and labrum under fluorescent microscopy D posterodorsal view of anterior section of funiculus (pedicel plus flagellum), evincing pedicel and antennomeres III and IV. Abbreviations: a 3 - 5, antennomeres III-V; abdsw, abductor swelling; bs, bubble stream; ce, compound eye; cl, clypeus; clb, clypeal lobe; clt, clypeal teeth; crcond, cranial condyle; md, mandible; mm, masticatory margins; lbs, labral chaetae; mdcond, mandible condyle; mxp, maxillary palps; oc, ocelli; occ, occipital carina; pd, pedicel; prvmdpr, posteroventral mandible process; sc, scape. Scale bars: 0.2 mm (A, B); 0.1 mm (C); 0.02 mm (D).

Figure 14. Holotype of † Camelosphecia fossor sp. nov. A profile of left side of body B profile of right side of body C dorsal view of mesosoma D delimited area of C under fluorescent light E details of the legs, especially the forelegs. Abbreviations: A 2 - A 3; abdominal segments 2 and 3; aprntr, anterior pronotal rim; ca, calcar; mscx, mesocoxa; msfm, mesofemur; msnt, mesonotum; mspl, mesopleural region of mesopectus; mssctm, mesoscutum; mssctl, mesoscutellum; mtcx, metacoxa; mtfm, metafemur; mtpl, metapleural region of metapectus; plant, plantulae; pr, prora; prcx, procoxa; pretc, pretarsal claws; prfm, profemur; prnt, pronotum; prop, propodeum; proppj, propodeal projection; prots, protarsomeres I and II chaetae; prtbss, distal protibia stout chaeta; psctc, parascutal carina; sp, propodeal spiracle; strg, strigil. Scale bars: 0.2 mm.

Figure 15. A-C † Camelosphecia spp. females examined by images. Specimens in A (BALBuTJ _ 36) and C (BALBuTJ _ 40) are likely conspecifics to † C. fossor. Specimen in B (BALBuTJ _ 38) is probably another species in the genus, not described in here (images by Phil Barden, used with permission) D, E are generalized schemes of † Camelosphecia habitus and forewing, respectively, as interpreted from all specimens examined. Metathoracic sclerites in A-C are indicated with green dots. In D, pedicel and flagellomeres are omitted for simplification. Abbreviations as in Figure 14, except for prstA 4, presternite of A 4; prpl, propleuron; tbsp, tibial spurs; stA 4, sternite of A 4; stng, sting. Wing venation abbreviations: C, costal vein; Sc, subcostal vein; R, radial vein; Rs, radial sector vein; M, medial vein; Cu, cubital vein, A, anal vein; +, indicates composite vein; f , indicates free abscissa index; 2 r-rs, second radiosectoral crossvein; 2 rs-m, second sectoriomedial crossvein; 1 m-cu, first mediocubital crossvein; 1 cu-a, first cubitoanal crossvein; R (bc), radial or " basal " cell; 1 + 2 R (smc 1), undifferentiated first and second distal radial cells or " first submarginal cell "; 3 R (mc 1), third distal radial or " first marginal " cell; 1 Rs (smc 2), first sectorial or " second submarginal " cell; 1 M (dc 1), first medial or " discal " cell; 1 Cu (sbc), first cubital or " subbasal " cell; 2 Cu (sdc 1), second cubital or " first subdiscal " cell.

Figure 16. † Camelosphecia venator sp. nov. holotype (NIGP 163574) A, D right and left profile view of body, respectively B, C right and left profile view of head, respectively E left mesosoma zooming. Abbreviations: ce, compound eye; cl, clypeus; md, mandible; mm, masticatory margins; oc, ocelli; occ, occipital carina; A 2 - A 3; abdominal segments 2 and 3; mscx, mesocoxa; mspl, mesopleural area of mesopectus; mssctm, mesoscutum; mtcx, metacoxa; mtpl, metapleural area of mesopectus; oms, oblique mesopleural sulcus; pr, prora; prcx, procoxa; prnt, pronotum; prop, propodeum. Note that indication of clypeus in C is exactly at its margin as seen in profile, which is concave, and should not be confused with convex right compound eye margin, also indicated. Clypeal concave shape is better evidenced in figure B. Also in C, mm indicated is from the right mandible, while mandible indicated is that of the left side. Scale bars: 1 mm (A, D); 0.2 mm (B, C, E).