Taiping Gao

Mid-Mesozoic Flea-like Ectoparasites of Feathered or Haired Vertebrates

Parasite-host associations among insects and mammals or birds are well attended by neontological studies [1]. An Eocene bird louse compression fossil [2, 3] and several flea specimens from Eocene and Oligocene ambers [4-8], reported to date, are exceptionally similar to living louse and flea taxa. But the origin, morphology, and early evolution of parasites and their associations with hosts are poorly known [9, 10] due to sparse records of putative ectoparasites with uncertain classification in the Mesozoic, most lacking mouthpart information and other critical details of the head morphology [11-15]. Here we present two primitive flea-like species assigned to the Pseudopulicidae Gao, Shih et Ren familia nova (fam. nov.), Pseudopulex jurassicus Gao, Shih et Ren genus novum et species nova (gen. et sp. nov) from the Middle Jurassic [16] and P. magnus Gao, Shih et Ren sp. nov. from the Early Cretaceous in China [17]. They exhibit many features of ectoparasitic insects. Large body size and long serrated stylets for piercing tough and thick skin or hides of hosts suggest that these primitive ectoparasites might have lived on and sucked the blood of relatively large hosts, such as contemporaneous feathered dinosaurs and/or pterosaurs or medium-sized mammals (found in the Early Cretaceous, but not the Middle Jurassic).

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

Fleas are a group of highly specialized blood-feeding ectoparasites whose early evolutionary history is poorly known. Although several recent discoveries have shed new light on the origin of the group, 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.

The First Xyelotomidae (Hymenoptera) from the Middle Jurassic in China

ABSTRACT Three new genera with three new species and two new species of two known genera, all in the family of Xyelotomidae (Hymenoptera), are described and illustrated. These specimens were collected from the Middle Jurassic of Daohugou, Jiulongshan Formation, and the Late Jurassic to Early Cretaceous of Dawangzhangzi, Yixian Formation, of China. A key to the known and new genera of Xyelotomidae is provided. Fourteen fossil genera with 20 species found so far from the Early Jurassic to the Early Cretaceous imply that Xyelotomidae was diverse and abundant during that period. New findings reported here provide additional evolutionary and transitional evidence of forewing Sc vein changed from two-branched to one-branched, to two separate parts, to apical part forming a crossvein, and finally to vestigial in Xyelotomidae from the Early Jurassic to the Early Cretaceous.

Hoplitolyda duolunica gen. et sp. nov. (Insecta, Hymenoptera, Praesiricidae), the Hitherto largest sawfly from the Mesozoic of China.

Background Large body size of an insect, in general, enhances its capability of predation, competition, and defense, resulting in better survivability and reproduction. Hymenopterans, most being phytophagous or parasitic, have a relatively small to medium body size, typically under 50.0 mm in body length. Principal Findings Herein, we describe Hoplitolyda duolunica gen. et sp. nov., assigned to Praesiricidae, from the Early Cretaceous Yixian Formation of China. This new species is the largest fossil hymenopteran hitherto with body estimated >55.0 mm long and wing span >92.0 mm. H. duolunica is, to our knowledge, the only sawfly with Sc present in the hind wing but not in the forewing. Its Rs1 and M1 meeting each other at 145° angle represents an intermediate in the transition from “Y” to “T” shapes. Even though Hoplitolyda differs significantly from all previously described genera in two subfamilies of Praesricidae, we leave the new genus unplaced in existing subfamilies, pending discovery of material with more taxonomic structure. Conclusions/Significance Hoplitolyda has many unique and interesting characters which might have benefitted its competition, survival, and reproduction: large body size and head with robust and strong mandibles for defense and/or sexual selection, unique wing venation and setal arrangements for flight capability and mobility, dense hairs on body and legs for sensing and protection, etc. Considering the reported ferocious predators of feathered dinosaurs, pterosaurs, birds, and mammals coexisting in the same eco-system, Hoplitolyda is an interesting case of “survival of the fittest” in facing its evolutionary challenges.

The first Praesiricidae (Hymenoptera) from Northeast China

Abstract A new subfamily Rudisiricinae Gao, Rasnitsyn, Ren & Shih, n. subfam. and a new genus Rudisiricius Gao, Rasnitsyn, Ren & Shih, n. gen. with three new species R. belli Gao, Rasnitsyn, Ren & Shih n. sp., R. crassinodus Gao, Rasnitsyn, Ren & Shih, n. sp., and R. celsus Gao, Rasnitsyn, Ren & Shih, n. sp. are described and illustrated from the family Praesiricidae. The type specimens were collected from the Late Jurassic to Early Cretaceous Yixian Formation, northeastern China. The new subfamily also includes Aulidontes Rasnitsyn from the Upper Jurassic of Karatau in Kazakhstan. This is the first record of Praesiricidae in China. These well-preserved nearly-complete new fossils reported here provide additional material and structure characters about this family, which helps filling some gap in the evolution of Lower Hymenoptera.

A New Xyelydid Sawfly from the Early Cretaceous of China (Hymenoptera: Xyelydidae)

Abstract Novalyda cretacica, new genus and new species (“Symphyta”: Pamphilioidea: Xyelydidae), is described based on a unique male from the Early Cretaceous, Yixian Formation of northeastern China. The new species differs from others in the family by its relatively thick antenna, narrow costal cell, short first abscissa of Rs, sclerotization of the pterostigma. The species is the youngest occurrence of the family and extends the lineage into the Cretaceous period.

The first flea with fully distended abdomen from the Early Cretaceous of China.

BackgroundFleas, the most notorious insect ectoparasites of human, dogs, cats, birds, etc., have recently been traced to its basal and primitive ancestors during the Middle Jurassic. Compared with extant fleas, these large basal fleas have many different features. Although several fossil species with transitional morphologies filled the evolutionary blank, the early evolution of these ectoparasites is still poorly known.ResultsHere we report a new flea with transitional characters, Pseudopulex tanlan sp. nov., assigned to Pseudopulicidae, from the Lower Cretaceous Yixian Formation of Liaoning Province, China. Different from the previously described pseudopulicids, P. tanlan has relatively smaller body size but lacking any ctenidia on the tibiae or body, while the male with comparatively smaller and shorter genitalia. On the other hand, P. tanlan has some characters similar to the transitional fleas of saurophthirids, such as, a small head, short compacted antennae, small pygidium and many stiff setae covering the body.ConclusionsEven though other possibilities can not be ruled out, the female specimen with extremely distended abdomen suggests that it might have consumed its last meal before its demise. Compared with other reported female flea fossils, we calculate and estimate that P. tanlan sp. nov. might have consumed 0.02 milliliter (ml) of blood, which is about 15 times of the intake volume by extant fleas. These new findings further support that fleas had evolved a broad diversity by the Early Cretaceous.

Convergent evolution of ramified antennae in insect lineages from the Early Cretaceous of Northeastern China.

Antennae are important, insect sensory organs that are used principally for communication with other insects and the detection of environmental cues. Some insects independently evolved ramified (branched) antennae, which house several types of sensilla for motion detection, sensing olfactory and chemical cues, and determining humidity and temperature levels. Though ramified antennae are common in living insects, occasionally they are present in the Mesozoic fossil record. Here, we present the first caddisflies with ramified antennae, the earliest known fossil sawfly, and a scorpionfly also with ramified antennae from the mid-Lower Cretaceous Yixian Formation of Northeastern China, dated at 125 million years ago (Ma). These three insect taxa with ramified antennae consist of three unrelated lineages and provide evidence for broad structural convergence that historically has been best demonstrated by features such as convergent mouthparts. In addition, ramified antennae in these Mid-Mesozoic lineages likely do not constitute a key innovation, as they are not associated with significantly increased diversification compared with closely related lineages lacking this trait, and nor are they ecologically isolated from numerous, co-occurring insect species with unmodified antennae.

Stick insect in Burmese amber reveals an early evolution of lateral lamellae in the Mesozoic

Extant stick and leaf insects commonly imitate twigs or leaves, with lateral lamellae used to enhance crypsis or achieve mimicry for protection. However, the origin and early evolution of such lateral expansions among Phasmatodea are unknown, because all known Mesozoic phasmatodeans hitherto lack preserved evidence of such structures. We report here the first Mesozoic stick insect, Elasmophasma stictum gen. et sp. nov., with well-preserved, thin, lateral lamellae on the thoracic pleura, the terga of abdominal segments I–X and the ventrolateral margins of all femora. This new species, from the mid-Cretaceous amber of northern Myanmar, has a clear, stick-like body and is assigned to Euphasmatodea. The abdominal structures of E. stictum exhibit traces of multiple expansions of the terga, suggesting that such structure might have been an early development of body expansions used to improve crypsis for stick or leaf insects when they sprawled on twigs or leaves.

Maternal care by Early Cretaceous cockroaches

Most cockroaches produce a special capsular structure, the ootheca, to enclose eggs for protection and maternal brood care. However, the origin and early evolution of the cockroach ootheca is poorly known, attributable to a lack of fossil evidence from the Mesozoic. Here, we report the earliest known cockroach fossil possessing an internally partitioned ootheca: Piniblattella yixianensis Gao, Shih & Ren sp. nov. is described from the mid Early Cretaceous Yixian Formation of China. The ootheca of this species measures 46–62% of its body length, contains 60–70 eggs, and exhibits the oviparity B reproduction mode, similar to that of the extant ectobiid and blattid cockroaches. In conjunction with several isolated ootheca specimens preserved in the mid-Cretaceous Myanmar amber (Burmite), we infer that the cockroach reproductive mode using the complete oothecate structure occurred during or before the mid Early Cretaceous. Maternal care associated with the oothecate condition in these Cretaceous cockroaches added a unique and major life-history trait, later resulting in true viviparity. This new life-history trait providing maternal protection and care may have been a key factor in the subsequent evolutionary diversification and ecological expansion of modern cockroach lineages. http://zoobank.org/urn:lsid:zoobank.org:pub:588C91F4-FB8D-43E5-8C2D-86D50393B851