Transitional fossil earwigs - a missing link in Dermaptera evolution

<p>Abstract</p> <p>Background</p> <p>The Dermaptera belongs to a group of winged insects of uncertain relationship within Polyneoptera, which has expanded anal region and adds numerous anal veins in the hind wing. Evolutional history and origin of Dermaptera have been in contention.</p> <p>Results</p> <p>In this paper, we report two new fossil earwigs in a new family of Bellodermatidae fam. nov. The fossils were collected from the Jiulongshan Formation (Middle Jurassic) in Inner Mongolia, northeast China. This new family, characterized by an unexpected combination of primitive and derived characters, is bridging the missing link between suborders of Archidermaptera and Eodermaptera. Phylogenetic analyses support the new family to be a new clade at the base of previously defined Eodermaptera and to be a stem group of (Eodermaptera+Neodermaptera).</p> <p>Conclusion</p> <p>Evolutional history and origin of Dermaptera have been in contention, with dramatically different viewpoints by contemporary authors. It is suggested that the oldest Dermaptera might possibly be traced back to the Late Triassic-Early Jurassic and they had divided into Archidermaptera and (Eodermaptera+Neodermaptera) in the Middle Jurassic.</p

New Transitional Fleas from China Highlighting Diversity of Early Cretaceous Ectoparasitic Insects

SummaryFleas are a group of highly specialized blood-feeding ectoparasites whose early evolutionary history is poorly known [1, 2]. Although several recent discoveries have shed new light on the origin of the group [3, 4], a considerable gap exists between stem fleas and crown fleas. Here we report a new transitional flea, Saurophthirus exquisitus sp. nov., assigned to a new family Saurophthiridae fam. nov., from the Lower Cretaceous Yixian Formation of northeastern China. Saurophthirids are more similar to crown fleas than other stem fleas in having a relatively small body size, relatively short and slender piercing-sucking stylet mouthparts, comparably short and compact antennae, rows of short and stiff bristles on the thorax, and highly elongated legs. The new finding greatly improves our understanding of the morphological transition to the highly specialized body plan of extant fleas. However, saurophthirids also display several features unknown in other fleas, and some of these features are suggestive of a possible ectoparasitic relationship to contemporaneous pterosaurs, though other possibilities exist. The new fossils, in conjunction with previous discoveries, highlight a broad diversity of ectoparasitic insects in the mid-Mesozoic

A golden orb-weaver spider (Araneae: Nephilidae: Nephila) from the Middle Jurassic of China

Nephila are large, conspicuous weavers of orb webs composed of golden silk, in tropical and subtropical regions. Nephilids have a sparse fossil record, the oldest described hitherto being Cretaraneus vilaltae from the Cretaceous of Spain. Five species from Neogene Dominican amber and one from the Eocene of Florissant, CO, USA, have been referred to the extant genus Nephila. Here, we report the largest known fossil spider, Nephila jurassica sp. nov., from Middle Jurassic (approx. 165 Ma) strata of Daohugou, Inner Mongolia, China. The new species extends the fossil record of the family by approximately 35 Ma and of the genus Nephila by approximately 130 Ma, making it the longest ranging spider genus known. Nephilidae originated somewhere on Pangaea, possibly the North China block, followed by dispersal almost worldwide before the break-up of the supercontinent later in the Mesozoic. The find suggests that the palaeoclimate was warm and humid at this time. This giant fossil orb-weaver provides evidence of predation on medium to large insects, well known from the Daohugou beds, and would have played an important role in the evolution of these insects

Jurassic scorpionflies (Mecoptera) with swollen first metatarsal segments suggesting sexual dimorphism

Background: Sexual dimorphism is widespread in insects. The certain specialized structures may be used as weapons in male–male combats or as ornaments to enhance mating opportunities. Results: We report striking swollen first tarsal segments in two families, four genera and six species of scorpionflies from the Middle Jurassic Yanliao Biota of Northeastern China. Swollen tarsal segments are restricted to male specimens and to hind leg tarsi. The geometric morphometric analyses reveal that the degree of swelling within the orthophlebiid species possessing swollen first metatarsal segments is species-specific, which can be used as a diagnostic character for taxonomic and phylogenetic studies. Conclusions: The new findings indicate that swollen first metatarsal segments are relatively common in the family Orthophlebiidae during the Middle Jurassic. The tarsal swellings are considered to be sexually dimorphic, potentially associated with sexually display by males and/or camouflage of a “nuptial gift” in the mating process

Proapocritus bialatus Li, Shih and Ren 2014, sp. nov.

Proapocritus bialatus Li, Shih and Ren sp. nov. (Figures 3, 4) Etymology The specific epithet is derived from the Latin word bialatus (a pair of wings), indicating the well-preserved and out-stretched wings. Material Holotype female CNU-HYM-NN-2012040. Locality and horizon Jiulongshan Formation, Daohugou Village, Shantou Township, Ningcheng County, Inner Mongolia, China; Middle Jurassic. Diagnosis Antenna slim, with more than 25 segments. Forewing with cu-a slightly postfurcal, 1r-rs vein reduced near R and pterostigma, 2r-m, 3r-m slightly bent (not vertical); 2mcu wavy curved; hind wing with 1-Rs originating not basad of M + Cu fork, 1-M and cu-a nearly parallel. First metasomal segment nearly trapezoid. Description Female wasp in dorsal view; left and right wings well preserved with main veins clearly discernible (Figure 3A, B). Body 15.8 mm long including the antennae and ovipositor (body 9.6 mm long excluding the antennae and ovipositor); the head transversely broad, about 0.9 mm long and 1.8 mm wide; antenna thin and well preserved, with 25 antennomeres and about 5.4 mm long, pedicel short and slightly narrower than distal part of the scape, flagellomeres equal in length and width; mesosoma long and slender, about 3.1 mm long and 1.9 mm wide; pronotum, mesonotum, mesoscutellum, metanotum, metascutellum and propodeum discernible (Figure 3A, B); the mesonotum with notauli nearly V-shaped and reaching transscutal suture; mesoscutellum slightly wider and longer than metanotum; propodeum longer than metanotum; metasoma 5.5 mm long excluding the ovipositor, with six segments visible, the first metasomal segment nearly trapezoid, apical part about 1.5 times as wide as basal part. Ovipositor 5.2 mm long with sheaths; legs partially preserved and the hind legs longer and wider than the forelegs and mid legs. Forewing 6.7 mm long and 2.1 mm wide as preserved, with pterostigma long and acuminate, issuing 2r-rs at its mid-length (Figure 3A, B); the first abscissa of Rs (1- Rs, 0.3 mm long) subvertical to R and slightly shorter than that of M (1-M, 0.4 mm long); vein 1r-rs present but reduced near R and pterostigma, and the distance of 1r-rs to Rs base longer than that to 2r-rs base; vein 2r-rs slightly longer than the width of pterostigma and nearly as long as the maximal width of cell 2rm, and about half the length of 2rm, and subparallel to 1r-rs and 1-Rs; cell 1mcu nearly parallelogrammic, about 2.5 times as long as wide; vein 1m-cu (0.4 mm long) meeting 2rm slightly beyond Rs + M forking and slightly shorter than cu-a (0.5 mm long); vein cu-a slightly postfurcal, parallel to a 1 -a 2 and 1.6 times as long as a 1 -a 2; vein 2m-cu bending and 1.5 times as long as 1m-cu; vein 2A completely preserved. Hind wing 3.6 mm long and 1.5 mm wide as preserved, distinguishable with 1-Rs origin at the same level of M + Cu forking; cell r closed; vein r-m straight and 0.6 times as long as 1-Rs; the first abscissa of M (1-M) slightly arched and about three times as long as r-m; vein cu-a long and strongly oblique, meeting Cu beyond M + Cu forking; vein A present, free M and Cu long. Remarks and comparison The genus Proapocritus, 1975 was erected by a hymenopteran forewing from the Early or Middle Jurassic Kyrgyzstan, and tentatively placed in Karatavitidae (Karatavitidae was considered to be the most primitive apocritans). Proapocritus was considered to almost completely cover the hiatus between Karatavites of Symphyta and Ephialtitidae of Apocrita (Rasnitsyn 1975). Until 2010, Rasnitsyn and Zhang have reported six new species (Proapocritus densipediculus, Proapocritus sculptus, Proapocritus formosus, Proapocritus atropus, Proapocritus longantennatus, Proapocritus elegans) of this genus, all specimens from the Middle Jurassic Jiulongshan Formation at Daohugou Village of China. New and complete material not only provides new characters of this group but also broadens the diversity of Ephialtitidae. Proapocritus bialatus sp. nov. is assigned to to Proapocritus Rasnitsyn, 1975 because of the following characters: wings with complete venation, forewing with 1- Rs directed slightly posterodistally; 1r-rs, 2r-m, 3r-m, 2m-cu, 2A and a 1 -a 2 present; hind wing with enclosed cell r; Rs originating not basad of M + Cu fork and so on. This new species differs from other species (except Proapocritus densipediculus) of the genus Proapocritus in the forewing with cu-a slightly postfurcal (versus other species of the genus with cu-a intersitial); differs from Proapocritus densipediculus in forewing with 2r-m, 3r-m slightly bend and 2m-cu wavy curved and the first metasomal segment nearly trapezoid (versus Proapocritus densipediculus with 2r-m, 3r-m vertical while 2m-cu not preserved, and the first metasomal segment as wide as propodeal foramen, subcylindrical).Published as part of Li, LongFeng & Shih, ChungKun, 2014, Two new fossil wasps (Insecta: Hymenoptera: Apocrita) from northeastern China, pp. 829-840 in Journal of Natural History 49 (13) on pages 834-837, DOI: 10.1080/00222933.2014.953223, http://zenodo.org/record/400395