TAXONOMY AND TRUNK-RING ARCHITECTURE OF PLEUROJULID MILLIPEDES (DIPLOPODA: CHILOGNATHA: PLEUROJULIDA) FROM THE PENNSYLVANIAN OF EUROPE AND NORTH AMERICA

ABSTRACT-

Pleurojulid millipedes, known since the make go round of the last century to be relatively abundant in the Westphalian D (Carboniferous: Pennsylvanian) Gaskohl of N??rany, Czech Republic, are here also identified as an important constituting of the Pennsylvanian (Westphalian D) Mazon bight millipede fauna preserved in ironstone nodules. Pleurojulids reach longitudinal dimensionss approaching 10 cm, have as many as 69 material substance segments, medium-sized heads, and large ocellaria with upwards of 40 ocelli. Pleurojulids have previously been interpreted as having either a juliform-like or a colobognathan-like trunk-ring architecture. In order to distinguish between these sum of two units hypotheses, almost all pleurojulid specimens in museum collections were scaned to document the deformation pattern of exoskeletal simple bodys to aid in reconstruction of the trunk-ring architecture. The N??rany specimens are completely flattened while the Mazon small bay specimens retain a degree of three-dimensionality. In order to assess by what means trunk-ring architecture controls patterns of deformation, a variety of extant millipedes were experimentally shut firmlyed The distribution of exoskeletal uncompounded bodys in pleurojulid fossils was greatest in quantity similar to that seen in press togethered extant polyzoniid millipedes. Based upon the available evidence, pleurojulid trunk-ring architecture is construct agained as semicircular in cross section, consisting of arched diplotergites, independent pleurites firmly articulated to the lateral margins of the tergites and held in a near horizontal position, and at liberty sternites. Pleurojulida are hypothesized to be basal helminthomorph, the sister assemblage to Colobognatha, though inclusion in Helminthomorpha is equivocal. The taxonomy of previously described pleurojulid millipedes from N??rany is revised and newly recognized specimens from Mazon small bay specimens are described. Two genera are recognized within the of recent origin order Pleurojulida: Pleurojulus and Isojulus. sum of two units species of Pleurojulus are recognized: P biornatus and P levis. Pleurojulus aculeatus and P pinguis are synonymized with P levis. solitary one species of Isojulus, I. constans, is recognized with I. setipes, I. marginatus synonymized with it along with Pleurojulus longipes and P falcifer.

INTRODUCTION

THE UPPER Carboniferous strata at N??rany in the Czech Republic and Mazon inlet in Illinois comprise two of the greatest in quantity important Paleozoic Konservat-Lagerstatten for millipedes in particular and terrestrial arthropods in general. Millipedes are generally rare in the fossil record to be paid to their terrestrial habitus, on the contrary are superbly preserved and relatively abundant at these sum of two units localities. Many of the millipede taxa base at N??rany and Mazon bight were described around the make go round of the last century by dint of Fritsch (1899) and Scudder (eg 1889 1890) respectively. Of these taxa, sum of two units groups in particular have captured the attention of those who have dealings with the Paleozoic terrestrial arthropod faunas and have at short intervals been figured in textbooks and treatises: the spiny euphoberiids, to be paid to their fantastic armature, and the pleurojulids described by the agency of Fritsch (1899) from Nyrany, because of their ready acceptance as bona fide millipedes, owed in large part to their grand preservation. Many of the N??rany specimens are near consummate with heads, legs, and tergal microsculpture preserv Acceptance of pleurojulids as bona fide millipedes was a significant occurrence in millipede taxonomy. Historically, all Paleozoic millipedes had been placed in Archipolypoda, a separate class from extant millipedes, owed to mistaken morphological interpretations that l investigators to believe they were sufficiently anatomically different from extant millipedes as to debar accommodation within the existing taxonomic framework (for a review of the history of the taxon Archipolypoda and a rediagnosis, diocese Wilson and Anderson, 2004). With all the attention that has been given to pleurojulids, it is surprising to note that none were at any time previously described from Mazon cove (Baird and Anderson, 1997) smooth though, as documented herein, they comprise a large proportion of the known millipede fossils from this locality. However, the fossils have not gone completely unnoticed as Langford (1963) mistakenly identified individual or more specimens of Pleurojulus Fritsch, 1899 from Mazon bight as a soft-bodied annelid.

Superb preservation notwithstanding, the trunk-ring architecture of pleurojulid millipedes has been make subordinate to various interpretations. Fritsch (1899) envisioned pleurojulids as having juliform-like stalk rings, roughly circular in cros section, on the contrary with visible sutures delimiting the portion of the ring formed by means of the pleurite from that formed by the agency of the tergite. Silvestri (1903, p 103-105) interpreted these manner of makings as ventral paratergites (in his terminology = pure pleurites) and stated that the paratergites in Pleurojulidae were separate from the sternites as in Colobognatha. Sharov (1966 p 70) regarded the pleurites as paratergal lobes that were freely articulated with the tergites and which would have shoot forwarded laterally. In contrast, Hoffman (1969 p R595) viewed the line of junctions separating the tergites and pleurites simply as cracks that occurr when pleurotergites were flattened. Kraus (1974) supported the contention of earlier authors that the pleurites were discrete conformations It is implied by Dzik (1981) that he also accepted the discrete nature of the pleurites as he glance ated that Pleurojulus represents the oldestknown colobognath millipede, calling attention to the similarity in tergal morphology to that of Polyzonium Brandt, 1837 However, in light of the unspecialized nature of the pleurojulid head, Dzik (1981) also recommended that a relationship to the Platydesmida should be considered. greatest in quantity recently, Schneider and Werneburg (1998) reflected sounded Sharov (1966) in hypothesizing that the pleurites in Pleurojulus were oriented horizontally to form a cover over the legs.