Antennal Insertions Research Articles

A Fossil Paederinae from a Lacustrine Deposit at Orapa Diamond Mine in Botswana1

Abstract A staphylinid beetle morphotype, Mesostaphylinus orapa sp. n., is described based on a single well–preserved compression fossil from an Upper Cretaceous lacustrine deposit at Orapa Diamond Mine in Botswana. Mesostaphylinus Zhang is placed in the extant subfamily Paederinae based on general habitus and an unambiguous synapomorphy, the concealed antennal insertions. Mesostaphylinus is a genus of convenience for fossils belonging in Paederinae, but lacking diagnostic features (e.g., maxillary palpomeres) to assign and delineate them into appropriate tribes and subtribes. The fossil described here is morphologically similar to M. laiyangensis Zhang, M. fraternus Zhang, Wang and Xu, M. elongatus Solodovnikov and Yue, M. yixianus Solodovnikov and Yue, and M. antiquus Solodovnikov and Yue. Compared to other fossil staphylinid beetles that have been described thus far, the fossil also portrays morphological conservatism, morphological stasis, or arrested evolution dating back to the Cretaceous, thereby suggesting a punctuated equilibrium pattern of evolution.

Paleothius mckayi sp. n.: A New Species of Staphylininae (Arthropoda: Insecta: Coleoptera: Staphylinidae) from Orapa in Botswana1

Abstract A new species of a staphylinid beetle, Paleothius mckayi sp. n. is described using a single fossil from the Orapa Diamond Mine in Botswana. Paleothius is placed in the extant subfamily Staphylininae based on its general symmetrical habitus, typical sub-limuloid and elongated medium-to-large body form, elongated head, remarkably long antennomere 1, antennal density increasing apically, antennal insertions closer to the eye than to each other, tapering abdomen with two pairs of paratergites, and intersegmental membranes with ‘brick-wall’ pattern. It is separated from its sister clade Paederinae by having exposed antennal insertions and a small post-coxal process. It can be distinguished from all other Staphylininae by its significantly curved temples and large subtriangular pro-, meta- and meso-coxae. The specimen is preserved with flexed, distally-sharpened, extended or protruding scissor-like mouthparts. It is possible that it was primarily using these extended or protruding scissor-like mouthparts to actively hunt prey in leaf litter and other microhabitats in and around the crater lake at Orapa. This fossil further confirms the widespread distribution of staphylinines during the Cretaceous. Moreover, similarly to other previously described fossil staphylinine staphylinid beetles, it portrays morphological stasis, or morphological conservatism. This is also known as arrested evolution. Therefore, it provides evidence for punctuated evolution dating back to the Cretaceous. Moreover, it highlights that morphological similarities between Staphylininae and Paederine date back to the Jurassic period.

A new species of Anthonomus (Coleoptera: Curculioninae: Anthonomini) in the Anthonomus squamosus species group associated with Tiliaceae (Malvales)

Anthonomus petrus Soto-Hernández n. sp. is described based on specimens collected from Guatemala, Honduras, and Mexico (Chiapas, Michoacán and Zacatecas); it is associated with Heliocarpus and Triunffeta (Malvales: Tiliaceae). The species can be easily recognized by the following diagnostic characters: rostrum in both sexes with distinct, elongate scales present beyond point of antennal insertion; body elongate-oval, length 2.1-2.8 mm, body and rostrum with uniform vestiture of elongate, ochreous scales; rostrum toward apex slightly expanded; scape longer than funicle and club combined; scutellum convex and triangular.

Trilobite hypostome as a fusion of anterior sclerite and labrum

The trilobite hypostome is a biomineralized ventral plate that covers the mouth, but its evolutionary origin remains controversial. The labrum is a lobe-like structure that can take on variety of shapes in front of the mouth in arthropods, while the anterior sclerite refers to a cuticular plate articulated to the anterior margin of the head in some Cambrian arthropods. Here I present a perspective that views the trilobite hypostome as a fusion of the anterior sclerite and the labrum based on anatomical, topological, and developmental evidence. According to this perspective, the anterior lobe of the hypostome originated from the anterior sclerite, while the posterior lobe reflects a remnant of the sclerotized cover of the labrum. The convex anterior lobe housed the root of the eye stalks, represented by the palpebral ridges and the hypostomal wing, and the posterior lobe occasionally developed a pair of posterolateral extensions, as do the labra. The position of the antennal insertion was located in front of the posterior lobe, displaying a similar topology to the Cambrian arthropods with the labrum. The hypostome was present in many artiopodans except for the Conciliterga, in which the anterior sclerite was separate from the labrum.

An aberrant colydiine-like tenebrionoid beetle from mid-Cretaceous Burmese amber (Coleoptera: Tenebrionoidea: Zopheridae)

A new fossil species of the superfamily Tenebrionoidea, Coslonatus rasnitsyni gen. et sp. nov., is described and illustrated from the mid-Cretaceous Burmese amber. The new genus is tentatively placed in the extant subfamily Colydiinae (Zopheridae) based primarily on the 4-segmented tarsi, clubbed antennae, and all freely connected abdominal ventrites. Coslonatus is unique in Colydiinae in having dorsally located antennal insertions and markedly long antennae, suggesting a unique ecological niche of the new species.

A new genus of giant sooty mould beetles from mid-Cretaceous Burmese amber (Coleoptera: Cyclaxyridae)

The sooty mould beetles (Cyclaxyridae) are a small and relictual family of cucujoid beetles with only two extant species restricted to New Zealand. The systematic position of the family within Cucujoidea is unresolved, with morphological and molecular studies yielding a range of incongruent topologies. Here we describe a new cyclaxyrid genus and species, Pacyclaxyra azari gen. et sp. nov., from mid-Cretaceous Burmese amber mined in northern Myanmar (ca. 99 Ma). The new genus is separated from all other cyclaxyrids by its unusually large body size, dorsally concealed antennal insertions, narrowly separated procoxae, narrow prosternal process not expanded at apex, and presence of a distinct discrimen on metaventrite. Together with Electroxyra cretacea described from the same deposit, Pacyclaxyra gen. nov. represents the earliest sooty mould beetle in the fossil record. Considering the potentially plesiomorphic characters possessed by Pacyclaxyra azari gen. et sp. nov., the implications for understanding the systematic position of Cyclaxyridae are discussed.

Specialised subcortical cylindrical bark beetles from mid-Cretaceous Burmese amber (Coleoptera: Zopheridae: Colydiinae)

ABSTRACT Cylindrical bark beetles (subfamily Colydiinae) are a group of mycophagous and predatory beetles placed in the family Zopheridae with a complicated taxonomic history and an unresolved phylogeny. We describe a new genus and two new species of strikingly cylindrical and elongate colydiid beetles from mid-Cretaceous Burmese amber mined in northern Myanmar (ca 99 Ma). Bifurderum minutum gen. et sp. nov. and B. donoghuei gen. et sp. nov. show a puzzling combination of characters including antennal and mandibular insertions concealed dorsally, 11-segmented antennae with a loose 2-segmented club, apical antennal segment not enclosed in the preceding antennomere, open procoxal cavities, prosternal process as wide as the maximum diameter of the procoxae and not expanding apically to close the procoxal cavities, narrowly separated metacoxae, and tarsi simple. The unusual body form of Bifurderum gen. nov. points towards a predatory life inside the galleries of wood-boring insects. The new fossils substantially expand the known range of morphological disparity in Mesozoic colydiid beetles and suggest that adaptation for life in the galleries of xylophagous insects in cylindrical bark beetles evolved by the mid-Cretaceous.

Sexual Dimorphism in Anthonomus santacruzi (Coleoptera: Curculionidae): a Biological Control Agent of Solanum mauritianum Scopoli (Solanaceae)

There is evident variation in body size amongst Anthonomus santacruzi Hustache, 1924, weevils. The aims of this study were to assess if the variation in body size in A. santacruzi weevils is a result of sexual dimorphism and what features can be used to distinguish males from females. The weevils were collected from field sites in Mpumalanga, South Africa, where they were introduced as biocontrol agents of Solanum mauritianum Scopoli. Body structures and the presence/absence of the tergal notch was examined under an optical stereomicroscope and SEM to assess differences between sexes. The morphometric analysis of the body structures included rostrum length (base–apex and antennal insertion–apex), elytral length and width, pronotum length and width, first tarsus length, first tibia length, funiculus length and total body length. Rostrum length, elytra length and width and total body length were significantly larger in females than in males. A tergal notch in the 8th abdominal tergite was present in males and absent in females. The body structure; of rostrum length, elytra length and width and total body length overlapped between sexes in some specimens. The abdominal tergal notch was found to be the most useful body structure to distinguish males from females in A. santacruzi.

Mimicry in Cretaceous Bugs.

SummaryMimicry is ubiquitous in nature, yet understanding its origin and evolution is complicated by the scarcity of exceptional fossils that enable behavioral inferences about extinct animals. Here we report bizarre true bugs (Hemiptera) that closely resemble beetles (Coleoptera) from mid-Cretaceous amber. The unusual fossil bugs are described as Bersta vampirica gen. et sp. nov. and Bersta coleopteromorpha gen. et sp. nov. and are placed into a new family, Berstidae fam. nov. The specialized mouthparts of berstids indicate that they were predaceous on small arthropods. Their striking beetle-like appearance implies that they were either involved in defensive mimicry or mimicked beetles to attack unsuspecting prey. The latter would represent the first case of aggressive mimicry in the invertebrate fossil record. These findings enrich our understanding of the paleoecological associations and extinct behavioral strategies of Mesozoic insects.

†Rovnoleptochromus balticus sp. nov., a New Upper Eocene Ant-Like Stone Beetle

A leptochromine ant-like stone beetle, †Rovnoleptochromus balticussp. nov., is described, based on an exquisitely preserved inclusion in Upper Eocene Baltic amber from Kaliningrad Region. The holotype specimen reveals novel characters, not observed (presumably because of poorer preservation) in the previously known †R. ableptonoides Jaloszynski & Perkovsky of Rovno, Ukraine: three pairs of thick, long setae on the head (on vertex, near each eye and near each antennal insertion). Similar, presumably sensory structures (sensilla chaetica), are known in extant and extinct (Upper Cretaceous) Leptomastacini and the enigmatic Upper Cretaceous †Palaeoleptochromus O'Keefe. However, in these taxa, at most two pairs occur. The new finding broadens the known distribution of †Rovnoleptochromus during the Eocene, and suggests that the paired sensory bristles on the head may represent an ancestral condition in at least some of the tribes currently included in Mastigitae, which have later been partly or completely reduced in most members of this group.

Drilorhinus, a new genus of the family Drilidae Lacordaire, 1857 (Coleoptera: Elateroidea) from Iran.

A new genus of the family Drilidae, Drilorhinus gen. nov. with one new species D. klimenkoi sp. nov. from the South-West Iran (Lorestan) is described, illustrated and compared with all known genera of this group. The new genus differs from all members of the family in the strong projection of the anterior part of the frons between antennal insertions. Some problems of taxonomic rank and classification of Drilidae are considered.

Evolution of Mastigitae: Mesozoic and Cenozoic fossils crucial for reclassification of extant tribes (Coleoptera: Staphylinidae: Scydmaeninae)

Mastigitae is a supertribe of ant-like stone beetles (Scydmaeninae) that includes over 40% extinct genera, and whose evolutionary history is documented from the Upper Cretaceous through to today. Based on the results of phylogenetic analyses combining the most extensive taxon sampling to date, we reclassify Mastigitae into six monophyletic units: Leptomastacini, Clidicini sensu nov., Papusini trib. nov., Leptochromini trib. nov., †Baltostigini trib. nov. and Mastigini sensu nov. †Cretoleptochromus is placed as a junior synonym of Clidicus, and †Cascomastigus as a junior synonym of †Clidicostigus. Euroleptochromus setifer sp. nov. and Baltostigus striatipennis sp. nov. are both described from Upper Eocene Baltic amber. We postulate that Mastigitae have undergone differentiation into major lineages before the Cenomanian and that the Eurasian part of Laurasia was their ancestral distribution area. The reconstructed ancestor of Mastigitae was similar to the extant Scydmaenini, but with broadly separated antennal insertions and deep elytral striae. Four independent wing losses were inferred in Mastigitae. We present the first complete μCT reconstruction of the aedeagus in a fossilized scydmaenine, crucial for understanding the more than 99 million year long evolution of one of the most bizarre, asymmetrical aedeagi in the Coleoptera.

Foranotum perforatum gen. et sp. nov.-a new troglobitic darkling beetle (Coleoptera: Tenebrionidae: Kuhitangiinae: Foranotini trib. nov.) from a cave in Southern Zagros, Iran.

The troglobitic darkling beetle Foranotum perforatum gen. et sp. nov. from a cave in Southern Zagros Mountains (Iran) is described. This new taxon belongs to the family Tenebrionidae based on the following combination of characters: tarsal formula 5-5-4, antennal insertions concealed from above, antennae 11-segmented, mesocoxal cavities laterally closed by meso- and metaventrite. It is close to Kuhitangia kryzhanovskii Medvedev, 1962 by sharing a similar structure of procoxa (open cavities), labrum (reduced tormal arms) and prothorax (perforating holes on lateral sides of disc). Based on a comprehensive character analysis the subfamily Kuhitangiinae (type genus Kuhitangia Medvedev, 1962) is reestablished. Kuhitangiinae belongs to the pimelioid branch of the family Tenebrionidae based on open mouthparts (mentum small, exposing most of maxillae), mesocoxae externally closed by meso- and metaventrite, metacoxae externally narrowly closed by metaventrite and first abdominal ventrite, tentyrioid structure of abdominal ventrites (absence of membranes between abdominal ventrites 3-5) and absence of defensive glands. The subfamily Kuhitangiinae is divided into following two tribes: Kuhitangiini with a single species Kuhitangia kryzhanovskii Medvedev, 1962 and Foranotini trib. n. with Foranotum perforatum sp. nov. The new tribe differs from Kuhitangiini by the presence of trochanters and epipleura, structure of pronotum, abdominal ventrites and sculpture of meso- and metaventrites.

A new species of Frontodendroidopsis (Coleoptera: Pyrochroidae: Pyrochroinae) from China, with a key to males of the three species

Frontodendroidopsis pennyi, a new species of fire-colored beetle, is described from two males taken along the South Fork of Yamu He, 1.3 km east of Lao Shibali, northwestern Yunnan Province, China at an elevation of 2250 meters. This is the third described Frontodendroidopsis, the others being F. gibbiceps Young, also from China and the Japanese F. ocularis (Lewis). A similar cranial modification, large compound eyes, and strongly pectinate antennae place the new species in Frontodendroidopsis, although the antennal pedicel is shorter. Unlike F. gibbiceps the antennal insertions are not swollen and the frons is not carinate. The conspicuously emarginate fifth ventrite exhibited by males F. pennyi and F. gibbiceps distinguishes both of these species from F. ocularis.

A new weevil, Aepyceratus hyperochus gen. et sp. nov., Aepyceratinae subfam. nov., (Coleoptera; Nemonychidae) in Burmese amber

A new weevil, Aepyceratus hyperochus gen. et sp. nov., Aepyceratinae subfam. nov., is described from mid-Cretaceous Burmese amber. The new subfamily differs from the previous Mesozoic subfamilies Brenthorrhininae, Eobelinae, Cretonemonychinae and Paleocartinae by the short lateral pronotal carina, stark convex eyes and basal antennal insertion. From the subfamilies Rhinorhynchinae and Cimberidinae, it is distinguished by the short lateral pronotal carina, exodontous mandibles and basal antennal insertion. The new subfamily differs from the subfamily Idiomacerinae by the distinct clypeolabral suture, elliptical protruding eyes, short antennomere 1, wide tarsi, short lateral carina on the pronotum, and exodontous mandibles.

Combined phylogenetic and morphometric information to delimit and unify the Triatoma brasiliensis species complex and the Brasiliensis subcomplex

“Triatoma brasiliensis species complex” was defined as a monophyletic group of the species: T. brasiliensis, T. juazeirensis, T. melanica, and T. sherlocki. An alternative grouping scheme proposed the concept of “Brasiliensis subcomplex” which included the former species together with T. melanocephala, T. petrocchiae, T. lenti, T. tibiamaculata, and T. vitticeps. To evaluate the relationship among these taxa we combined the results obtained with four mitochondrial genes (12S, 16S, COI and Cytb, adding to 1811bp) and geometric morphometric analysis of wings and heads. Panstrongylus megistus was included in the analysis as it was previously found related to T. tibiamaculata, T. melanocephala and T. vitticeps. The results of both molecular and morphometric approaches clearly grouped the species analyzed into two monophyletic units, supported by both genetic and wing variability. The first one (G1) comprises the four species originally included in the T. brasiliensis species complex plus T. lenti and T. petrocchiae. The second group (G2) was composed by T. melanocephala, T. tibiamaculata and T. vitticeps, and remarkably, P. megistus if considering wing variability and phylogenetic results. Nevertheless, geometric morphometrics of heads provided a quantitative measurement that discriminates Panstrongylus from the Triatoma species based on the position of the antennal insertion relative to eyes, as it is used as the generic distinctive character. The discrepancy among approaches questions the validity of this character to define Panstrongylus genus. Independently of the chosen group definition —“T. brasiliensis species complex” or “Brasiliensis subcomplex”—we propose to delimit it to species of G1 that are all associated with the Caatinga biome in the Brazilian Northeast. G2 are the ones associated with the Atlantic Forest biome.

Liliputella, a new genus of microscopic, wingless and blind Scydmaenini of the Bismarck Islands (Coleoptera, Staphylinidae, Scydmaeninae).

Liliputella microscopica gen. & sp. nov. is described and placed in the tribe Scydmaenini. This taxon is known from a single male collected on Dyaul Island, the Bismarck Archipelago (Papua New Guinea). With only 0.68 mm of body length, this beetle is one of the smallest within Scydmaenini. Liliputella microscopica is also blind, wingless, strongly flattened and lightly pigmented, suggesting a possible subterraneous habitat. Alternatively, a large and deep ventral cephalic cavity, a unique character not known in any other species of Scydmaeninae, may be a glandular structure indicative of myrmecophily or termitophily. Liliputella shares several interesting characters with genera that also include blind, wingless and presumably subterraneous species, Eudesis and Pseudoeudesis, e.g., humeral denticles, adjacent antennal insertions or strikingly short tarsi. Morphological structures of the new genus are compared with those of other Scydmaenini, and a preliminary identification key to the genera of this tribe is presented. Possible morphological adaptations of Liliputella to miniaturization are also discussed.

First fossil representative of the family omalisidae (Coleoptera, Elateroidea sensu lato) from the Baltic amber

The paper describes Jantarokrama utilis Kovalev et Kirejtshuk, gen. et sp. nov., the first fossil representative of the family Omalisidae from the Upper Eocene Baltic amber, which is similar to the Recent Phaeopterus unicolor Costa, 1856, but distinguished from the latter by the larger and not so slender body, smaller distance between antennal insertions, longer antennae, wider prothorax with very convex anterior edge of the pronotum, and particularly by five completely exposed abdominal ventrites. The diagnosis of the new genus among generic taxa of Omalisidae and its similarity to Berendtimirus Winkler, 1987 (Berendtimiridae) are discussed.

Phylogeny of the Homalotina (Coleoptera: Staphylinidae: Aleocharinae) based on morphology

AbstractThe aleocharine subtribe Homalotina Heer represents one of the most diverse lineages of Staphylinidae. Despite its wide distribution and diversity, the phylogenetic relationships of the subtribe remain poorly understood. Here, we present the first cladistic analysis of the Homalotina based on morphological data. The subtribe is hypothesized to be a monophyletic group consisting of seven genera (Anomognathus Solier, Cephaloxynum Bernhauer, Holisomimus Cameron, Homalota Mannerheim, Neomalota Cameron, Stenomastax Cameron, and Thecturota Casey). The dataset for phylogenetic analysis comprised 83 characters representing 245 character states derived from adult morphology. These data were analysed using equal weighting and implied weighting schemes (k = 1–6) and results support the monophyly of the subtribe based on two synapomorphic characters (complete postoccipital sutures on head, posterolateral margin of metacoxae with macrosetae) and three homoplastic characters (medial setae on prementum not extended to apex of ligula, medial setae on labium contiguous, posterolateral angle of elytron slightly sinuate). Generic relationships differ in each analysis within the Homalotina (EW, IW with k = 1, 2–4, 5–6) although there are some identical topologies among the IW trees. Clades A, B, C, D, H, J and G were resolved as monophyletic in all weighting regimes. The monophyly of the genera is relatively well supported except for the genera Homalota and Stenomastax. Homalota species were recovered in four independent clades (clade C, D, I, K) and the Stenomastax species were recovered in two independent lineages. Candidates for the possible new genera are discussed. We herein transfer Homalota flavomaculata Bernhauer to the genus Stenomastax, resulting in the new combination [Stenomastax flavomaculata (Bernhauer)]. Our preliminary character correlation tests using phylogenetic pairwise comparisons did not support the hypothesis of association between flattened body form, and subcortical habitat and anterior shift of antennal insertion in Homalotini.

First artematopodid beetle in Mexican amber and its biogeographic implications (Coleoptera, Artematopodidae)

Wu, H., Coty, D. & Ding, M., 10.4.2015. First artematopodid beetle in Mexican amber and its biogeographic implications (Coleoptera, Artematopodidae). Alcheringa 39, xxx-xxx. ISSN 0311-5518Artematopodidae is a small polyphagan family forming one of the basal lineages of Elateroidea. Fossil artematopodids are rare and thus far confined to Eocene Baltic amber. Here, we report the first artematopodid, Electribius palaeomexicanus sp. nov., from Mexican amber. The fossil is placed in Electribius as supported by the following combination of characters: the presence of a setose cavity between the antennal insertion and eye, a shallow groove at the base of the pronotum connecting a pair of cavities, the elytral sutural stria deepened at the apex, and having an indistinct median part of suture between abdominal ventrites 3–5. Electribius palaeomexicanus is compared with all known Electribius species, and it is easily distinguished by its body colour, intercoxal process shape, and length of the longitudinal median ridge on ventrite 5. The new discovery suggests that the modern Central American endemic Electribius has survived in this region at least since the mid-Miocene. It provides new insights into the origin and evolution of Electribius through the Cenozoic.Hao Wu [mason007343@163.com] and Ming Ding [dijanet@163.com], Zhejiang Museum of Natural History, No. 6 of West Lake Culture Plaza, Hangzhou, 310014, PR China; David Coty [coty.david@gmail.com], Muséum National d’Histoire Naturelle, Institut de Systématique, Evolution, Biodiversité, ISYEB, UMR 7205 CNRS UPMC EPHE, CP50, 45 rue Buffon, F-75005 Paris, France.