Piotr Wegierek

A new family of aphids (Hemiptera, Sternorrhyncha) from the Lower Cretaceous of Baissa, Transbaikalia.

Abstract The family Rasnitsynaphididae fam. n. has a unique combination of characters: 9-segmented antennae; rhinaria arranged in many transverse rows, surrounding the antennal segments; segment IX narrower than other segments of flagellum, always without rhinaria; cubitus branches separated; ovipositor present; siphuncular pores absent. The new family comprises the genus Rasnitsynaphis gen. n. with three species, Rasnitsynaphis ennearticulata sp. n., Rasnitsynaphis coniuncta sp. n., and Rasnitsynaphis quadrata sp. n., all from the Lower Cretaceous of Transbaikalia.

Juraphididae, a new family of aphids and its significance in aphid evolution

A revision of the Jurassic aphid family Genaphididae revealed that the type genus Genaphis did not have the characteristics usually attributed to this family. This discovery led to a series of taxonomic decisions. The diagnosis of the family Genaphididae is emended. The genera Aphaorus, Juraphis and Pterotella are moved to the Juraphididae, fam.n. The new family is included in the superfamily Palaeoaphidoidea. Additionally, two new species, Juraphis karataviensis sp.n. and Pterotella shartegensis sp.n., are described. Phylogenetic relationships among the taxa of Juraphididae, the position of the family, and the distribution and palaeoecology of the taxa are discussed.

The oldest Palaeoaphididae (Insecta: Hemiptera: Aphidomorpha) from the Late Jurassic/Early Cretaceous locality of Khotont (Mongolia)

A new genus and species of the aphid family Palaeoaphididae, Primpalaeoaphis khotontensis gen. et sp.n. is described from the Late Jurassic/Early Cretaceous locality of Khotont (Mongolia). This is the oldest representative of Palaeoaphididae.

Comparative morphology of the forewing base articulation in Sternorrhyncha compared with a representative of Fulgoromorpha (Insecta, Hemiptera).

The forewing articulation of single species from each of the four subgroups of Sternorrhyncha (Aleyrodomorpha, Aphidomorpha, Coccomorpha, Psyllomorpha) was examined by optical and scanning electron microscopy. The species were compared with a species of Cixiidae (Fulgoromorpha), as an outgroup of Sternorrhyncha. We present the results of a comparative analysis of the forewing articulation in these five groups, propose a standardized terminology and compare our findings with those previously reported. The wing base of all examined species is composed of the following structures: anterior and posterior notal wing process, first, second, and third axillary sclerites, tegula, and axillary cord. The number of elements included in the wing base and the surrounding area is the greatest in Cacopsyllamali, the most complicated species from Sternorrhyncha. Based on the shape of axillary sclerites and the number of elements forming the wing base environment, Orthezia urticae (Coccomorpha) and Cixius nervosus (Fulgoromorpha) are the most similar. Among Sternorrhyncha, the most similar axillaries are those of Aphis fabae and Orthezia urticae, which is congruent with existing classifications. In this paper we show that the four groups from Sternorrhyncha exhibit their own distinct wing base morphology.

Revised concept of the fossil genus Oviparosiphum Shaposhnikov, 1979 with the description of a new genus (Hemiptera, Sternorrhyncha, Aphidomorpha)

Abstract This paper presents a revision of the aphid genus Oviparosiphum, which is known from the Cretaceous period. Redescriptions of two species: Oviparosiphum jakovlevi Shaposhnikov, 1979 and Oviparosiphum baissense Shaposhnikov & Wegierek, 1989 are made, and an updated diagnosis of this genus is provided. Oviparosiphum baissense is the type species of a newly described genus Archeoviparosiphum gen. n. Five other species of Oviparosiphum are also transferred to the new genus. The basis for their separation from Oviparosiphum is the structure of the siphunculi and ovipositor. A key is provided to the genera of Oviparosiphidae.

The forewing of the Aphis fabae (Scopoli 1763) (Hemiptera, Sternorrhyncha): a morphological and histological study

Dorsal and ventral sides of the forewing of Aphis fabae (Scopoli 1763) (Sternorrhyncha, Hemiptera) were examined by scanning electron microscopy. Reinforcement elements on their surface as well as scale-like elements were described. Using histological methods, cross-sections of the material were done. They showed a two-layered membrane with a circular foramen inside. The course of veins and places of their bifurcation were followed. Common stem of radius (R), media (M), and cubitus anterior (CuA) veins were composed of separate tracheae, which ran separately at the beginning, then continued in a single tunnel, and finally disappeared. Nerves were not observed. Neither were tracheae visible on the further course of those veins. The presence of a devoid-of-trachea costal vein was confirmed. Under scanning electron microscope, convex reinforcements on dorsal side of the wing turned out to be more sclerotized parts of chitin, not giving a zigzag-like profile of the wing on sections. In this paper, we show for the first time a cross-section of a very delicate wing of an aphid representative.

Morphological description of the alimentary tract of Geoica utricularia (Passerini, 1856) (Insecta, Hemiptera, Eriosomatinae).

Existing literature data report the lack of stomach and crenated intestine in the aphid species Geoicasetulosa (Passerini, 1860), a representative of subfamily Eriosomatinae. This odd anatomical feature seemed remarkable, due to the presence of fully developed intestine in closely related genera and mutualistic relationship with ants of this genus. The study aimed at repeated anatomical research of Geoicautricularia (Passerini 1856), in order to confirm what seemed to be a generic feature. Standard histological methods were applied, with addition of oblique light microscopy, fluorescence microscopy and confocal laser scanning microscopy. The results indicated the existence of a fully developed intestine, with broad sac-shaped stomach and loops of the crenated intestine. The general anatomy of the alimentary tract of G. utricularia resembles that of other representatives of the tribe Fordini. Also well-developed rectal gland is present, most probably playing a role in modifying the carbohydrate composition of excreted honeydew.

New mayfly genera from the Middle Triassic of Poland and their evolutionary and paleogeographic implications (Ephemerida: Litophlebiidae, Vogesonymphidae)

Two new mayfly genera and species from the Triassic deposits of the Pałęgi area (southeast Poland) are described. This is the first description of aquatic insects from the Pałęgi locality. Triassolitophlebia palegica gen. et sp. nov. (Litophlebiidae) is established on the basis of an isolated forewing. This is the first finding of this family in the Northern Hemisphere, known previously only from the Molteno Formation (South Africa). This is also the first mayfly family from the Triassic which has been found in both Hemispheres, providing additional evidence of the presumed similarity of aquatic insect faunas in the Southern and Northern Hemispheres during the Triassic. The consistent wing venation of ancient mayflies with homonomous wings could be evidence that they originated from the same ancestor. The second new mayfly, Palegonympha triassica gen. et sp. nov. (Vogesonymphidae), is described on the basis of a single fossil nymph (imprint of the exuviae) and indicates the similarity of the Pałęgi arthropod assemblage to that described from the Middle Triassic of France. The presence of a mayfly nymph in the last instar stage suggests not only that the Pałęgi deposit represents a fluvial environment with well-oxygenated and limpid water but also that these conditions lasted long enough to allow for such development.

Is there a relationship between the morphology of the forewing axillary sclerites and the way the wing folds in aphids (Aphidomorpha, Sternorrhyncha, Hemiptera)?

The present study describes the relationship between the morphology of the forewing axillary sclerites and the way the wings fold among 24 aphid genera as compared to a representative of coccids. Architecture of the forewing base was imaged with scanning electron and optical (fluorescence) microscopy. Significant differences in morphology of axillary sclerites between aphid species were observed, despite their belonging to one infraorder. Detailed description of 41 features of axillary sclerites was made. There was no difference between axillaries of viviparous (Aphididae) and oviparous (Adelges sp., Phylloxera sp.) species. No clear relationship between morphology of the axillary sclerites and the wing folding could be confirmed. Instead, the thorax structure determines the way the wing folds in aphids. Phylogenetic analysis based on our results cannot be conducted at this stage of study. To show how three-dimensional the structures are and how difficult to describe, a short animation of Aphis fabae (Aphididae) wing base was added. This is a preliminary study about morphology of axillary sclerites among aphids.

Morphological and histological study of the forewing of Orthezia urticae (Linnaeus, 1758) (Hemiptera, Sternorrhyncha)

Abstract Wings of Orthezia urticae males were studied. Both ventral and dorsal surfaces of wings were examined under light and scanning electron microscopes. The structure regarded as vein cubitus anterior turned out to be a reinforcement element only. Two elements known as radius sector and media are almost transparent depressions in the wing membrane. Veins at the margin of the fold of the wing anal lobe were not confirmed. Studies indicated a row of sensilla cupola at the beginning of the subcostal ridge. Cross sections of the wing membrane showed a two-layered membrane. The presence of two veins was confirmed in a common stem – subcostal and radius. The change of common stem shape was described. Neither tracheae nor nerves were observed. This is the second paper on cross-sections of wing within Sternorrhyncha.