Parisognoriste, a new genus of Lygistorrhinidae (Diptera: Sciaroidea) from the Oise amber with redescription of Palaeognoriste Meunier

Abstract A new genus and a new species of Lygistorrhinidae, Parisognoriste eocenica is described from the Eocene Oise amber of the Paris Basin. Parisognoriste sciariforme Meunier, 1904 and Parisognoriste affine Meunier, 1912 are re-described. Lectotypes are designated for both species of Palaeognoriste. The phylogenetic positions of the new genus and Palaeognoriste Meunier are discussed. The paper is an example demonstrating a new approach in cybertaxonomy including automatic generation of manuscript within Virtual Research Environment (Scratchpads), semantic enhancements, and parallel release of the publication on paper and on-line accompanied with registration of new taxa with ZooBank.


Introduction
Th e Le Quesnoy locality, near Houdancourt (Oise), has yielded fossiliferous amber associated with abundant plant remains and a diverse vertebrate fauna in sediments (Nel et al. 2004). Its age is lowermost Eocene and the infrared spectra (KBr) of Le Quesnoy and Baltic ambers are very diff erent, with that of the former more similar to the Recent Hymenaea copal. Only a small fraction of the insect genera and even fewer species of the Oise amber (also known sometimes as Paris Basin amber) are also present in Baltic amber (Nel et al. 2005). Th e palaeoclimate of Oise amber corresponds to the maximum global warming of the Palaeocene-Eocene boundary, which could partly explain the diff erences of it's fauna from the fauna of Baltic amber.
A number of specimens of Sciaroidea were discovered in the Oise amber, of which perhaps the most interesting are several specimens of a lygistorrhinid fl y. Th e purpose of the present paper is to describe this new taxon and discuss its systematic position. Superfi cially, it is similar to Palaeognoriste Meunier, the two species of which were described from Baltic amber in the early 20th century. Meunier (1904) described the fi rst, Palaeognoriste sciariforme, from the Königsberg collection of Baltic amber, based on a male and a female found in two separate pieces of amber, and erected a new genus, Palaeognoriste, to accommodate it. Later, he described another species, P. affi ne, based on two specimens found in copula in a single piece of amber (Meunier 1912). Unfortunately, both descriptions were very short and vague. To adequately describe the new genus from the Oise amber and to compare it with known fossil and recent taxa it was necessary to re-describe both species of Palaeognoriste and designate lectotypes for both species.

Material and methods
Th e piece of Oise amber containing three female specimens of the new species was cut in two for better observation and polished on a slab of diatomite. Type material of both species of Palaeognoriste was also studied. Fortunately, the specimens were not lost during World War II, as many of Meunier's other types were. Th e type of P. affi ne was kept in Geowissenschaftlisches Zentrum der Georg-August-Universität, Göttingen. In 2007, VB found syntypes of P. sciariforme in the Laboratory of Entomology, Muséum national d'Histoire naturelle, Paris, where they had been borrowed by the late Prof. L. Matile several years previously. Digital photography was undertaken using Zeiss Axioskop compound microscope and Canon EOS450D camera, the resulting images then being combined to increase depth of fi eld using Helicon Focus v. 4.77 software. All images are available at Fungus Gnats Online website (www.sciaroidea.info).
Th e descriptions of new taxa and redescription of known species were prepared on the Fungus Gnats Online Scratchpad as an initial stage of testing online taxonomic workfl ow as described in Blagoderov et al. (2010). Th e paper has been semantically tagged and enhanced using the Pensoft Mark Up Tool (PMT) which is based on the US National Library of Medicine's DTD (Document Type Defi nitions) TaxPub extension (http://sourceforge.net/projects/taxpub). Th e fi nal XML output of the paper has been archived in PubMedCentral, a PDF uploaded in the Biodiversity Heritage Library (BHL), and all revised species registered in ZooBank .
Diagnostic description. Small lygistorrhinid fl ies. Proboscis small, about 1/3 of the height of head, palpus four-segmented, much longer than proboscis. Ocelli three, median ocellus smaller than the lateral ocelli. Scutum moderately convex, laterotergite bare. Vestiture of tibiae in rows on apical part. Outer tibial spurs 2 and 3 shorter than inner. Hind leg much longer that fore and mid leg, but its tibia and tarsus only slightly expanded. Wing membrane without macrotrichia. Sc joining C. R1 short, approximately half of wing length. Rs distinct. Crossvein m-cu present, aligned with r-m. M1 and M2 fork base and M stem weak or reduced. M3+4 and CuA without a common stem. R1 setose, Sc, R5, M, and CuA bare.
Etymology. Th e genus name is compound word formed from parisos (Greek πάρǐσος, almost equal, just alike) and the genus name Gnoriste. Th e name is feminine.
Discussion. Parisognoriste resembles Archaeognoriste from the Upper Cretaceous Burmese amber, but the latter has palpi longer than head height, frons membranous, all longitudinal wing veins setose, Sc ending free, R1 longer than half wing length, M stem and base of M1 and M2 fork distinct and the tibial spurs of equal length. Parisognoriste is similar to Palaeognoriste Meunier but the latter has a long proboscis, one-segmented palpus and club-shaped hind tibia (see also under Phylogenetic analysis).  (Nel et al. 2004).

Parisognoriste eocenica
Paratypes: two inclusions of females in the same piece of amber (during preparation the piece was cut into two), deposited in the Muséum national d'Histoire naturelle, Paris: MNHN A32914 (PA876).
Th orax. Scutum uniformly setose with lateral and posterior setae being longer. Scutellum with 10 marginal setae, which are as long and strong as the setae on the posterior part of scutum. Anteprontum with fi ve setae, proepisternum with three setae. Pleural pit inconspicuous. Anepimerone pointed ventrally, touching katepisternum in single point. Laterotergite not produced strongly laterally, bare. Mediotergite non-setose, not convex posteriorly. Metepisternum trapezoidal, with height almost equal to width.
Legs. Procoxa longer than the others. Metacoxa with a row of long posterolateral setae. Protibia about the length of profemur. Tibial organ with a small lobe, but without any distinct setation. Metatibia not conspicuously expanded apically but steadily widening from base to apex, its apical width ca. 2x the basal width. Th e vestiture on the apical third of tibia in rows. Spur formula 1:2:2, mesotibia with inner spur 2x the outer, metatibia with inner spur 2.5x the outer. Claws 1-3 pointed. Abdomen. Cercus (Fig. 3) two-segmented, basal segment rounded, very short, apical segment oval, its length 2x the width. Sternite 8 wide, rounded apically.
Etymology. Th e species name is an adjective in the nominative singular, derived from the Eocene period, referring to the temporal distribution of the species.
Notes. Meunier (1904) described the species based on two specimens, a male and a female, in two separate pieces of amber. Th e present study revealed that they were not conspecifi c. For the sake of nomenclatural stability, we designate the male specimen, Z6630, as lectotype. Th e female specimen, Z5125, most probably belongs to Palaeognoriste affi ne (see under P. affi ne). Both specimens come from the Königsberg collection of Baltic amber, which was moved after World War II to Geowissenschaftlisches Zentrum der Georg-August-Universität, Göttingen (and currently on loan in the Laboratory of Entomology, Muséum national d'Histoire naturelle, Paris).
Head rounded, dichoptic, posteriorly with a row of short (40 μm) postoccipital bristles. Ommatidia round, equal in size. Interommatidial setae shorter than ommatidial diameter. Th ree ocelli, laterals 2x diameter of median, touching eye margin. Clypeus Th orax: Scutum uniformly setose, with supraalar setae longer than others. Scutellum with four longer subapical marginal setae and irregularly positioned shorter hairs. Antepronotum with three setae. Proepisternum with fi ve setae. Suture between anepisternum and katepisternum distinct. Anepimeron separated from katepisternum with indistinct ridge. Pleural pit distinct, cut into a dorsoventral corner of katepisternum. Laterotergite produced strongly lateroventrally, with a row of seven long setae. Metepisternum trapezoidal, with stronger sclerotized anterior margin, separated from metepimeron with a strong ridge. Mediotergite evenly curved.
Abdomen: Tergite 9 broadly curved posteriorly, with numerous short dark spines directed posteriorly and longer light setae directed ventrally at apex. Gonostyli narrow, fl attened, 4x longer than wide, each with two stout apical teeth and long dorsal mesial setae. Gonocoxite (Fig. 4) in lateral view with an obtuse angle on dorsal edge, a setae near the angle and two long setae near the base on gonostylus; covered with long setae ventrally. Paralectotype: female, Baltic amber, G1848 (BST.03.382), deposited in the Geowissenschaftlisches Zentrum der Georg-August-Universität, Göttingen, Germany; here designated.
Notes. Meunier (1912) described P. affi ne from a male and a female in copula. We here designate the male as lectotype and the female as paralectotype.
Head rounded, dichoptic. Ommatidia densely set, almost hexagonal, becoming slightly smaller dorsally. Interommatidial setae inconspicuous. Th ree ocelli present, diameterer of medial one 0.6x of the lateral ones, lateral ocelli touching eye margin. Antennae 2+14 segmented; fl agellomeres as wide as long, with one or two short dorsal setae and two short ventral spines each. Scape small, as long as wide, trapezoidal. Pedicel globular, slightly wider than fl agellum. Clypeus triangular, pointed. Palpus onesegmented, 0.56x length of labellum, with a row of dorsal setae. Labellum lanceolate at apex. Hypopharynx wide and strongly sclerotized.
Discussion. P. affi ne diff ers from P. sciariforme in having the male mid tarsal claws pointed, not blunt, base of M fork weak but distinguishable, M2 straight, not curved, at apex, weaker and fewer ventral setae on hind tarsomeres 1 and 2 (11 and four pairs contra 16 and six), dorsal margin of gonocoxites evenly curved, gonocoxites setose dorsally as well as ventrally, tergite 9 without longer apical setae. It is possible that the female specimen Z5125 is not conspecifi c with the paralectotype of P. affi ne. However, we consider the diff erences rather small, and they may be a result of post-embedding distortion, and until new material become available we prefer to refer the specimen to P. affi ne.
Parisognoriste and Palaeognoriste belong to the base of a clade of modern Lygistorrhinidae, diff erent from the Mesozoic taxa. Th is replacement corresponds to signifi cant changes of environment in the Upper Cretaceous and Palaeocene. Th us, we can hypothesise that gradual increase on length of the proboscis in Cainozoic taxa of Lygistorrhinidae refl ects wider distribution of nectar-bearing angiosperms in Palaeocene-Eocene.