A limulid trackway from the Late Jurassic (Tithonian) Lagerstätte of Canjuers (Var,France)

The first record of an invertebrate trackway from the lithographic limestones of the Canjuers Lagerstätte is described here. The preserved part of the trackway is approximately 39 cm long and 17 cm wide; it consists of two successive sets of imprints and the beginning of a third one. Two kinds of imprints have been recorded: the first one, well-preserved, is tetradactyl and the second one is straight, narrow and in sets of two or three imprints. The tracks described in this paper are similar to the type specimen of the ichnogenus Kouphichnium. The trackway, corresponding to locomotion behavior and left by a 26 cm wide specimen, can be related to the ichnospecies Kouphichnium lithographicum. This is the first evidence of a limulid from the Canjuers Lagerstätte.     

A Long Mortichnial Trackway of Mesolimulus walchi from the Upper Jurassic Solnhofen Lithographic Limestone near Wintershof,Germany

A 9.7 m long trackway was discovered in a plattenkalk quarry near the village of Wintershof, Bavaria, Germany, in 2002. The huge ichnofossil derives from the Lower Tithonian, Upper Jurassic Solnhofen Lithographic Limestone. The trackway is complete from beginning to end and consists of footprints, telson drag impressions, prosoma imprints and is identified as the ichnotaxon Kouphichnium isp. Preserved at the very end of the trackway is a complete specimen of Mesolimulus walchi confirming the trackway as a mortichnia (death march). Trackways and trace makers preserved together in the fossil record are rare and such specimens allow unique insights into behavior and ecology. The events that led to M. walchi preserved in this sediment are unknown; however, a most likely scenario is that the limulid was washed into the lagoonal environment during a harsh storm.     

First record of a xiphosuran trackway (<Emphasis Type="Italic">Kouphichnium</Emphasis> isp.) from the Jurassic of India

A 44 cm long trackway from the Kimmeridgian-Tithonian of the western Kachchh Basin represents the first evidence of the occurrence of members of the order Xiphosura in the Jurassic of India. The track consists of the imprints of the legs and the tail spine of a 36–44 cm long limulid and can be assigned to the ichnogenus Kouphichnium Nopsca, 1923. It was formed in a soft, silty to fine sandy substrate below the storm wave-base and preserved as a hyporelief at the base of a thin sandstone bed deposited by storm-induced currents. Eight different types of xiphosuran behaviour are known to be preserved as trace fossils: “swimming”, running, walking, crawling, mating, dying, ploughing, and resting. The present trackway from the Jurassic of India represents crawling, i.e., comparatively slow locomotion (Repichnia).     

Obituary: Ron K. Pickerill (1947–2018)

Recently discovered tracks in alluvial sediments of the Late Paleocene Bullion Creek Formation of western North Dakota have been identified as belonging to the large eusuchian crocodile Borealosuchus formidabilis and an associated small arthropod. They are described as two new ichnotaxa. The first of these, Borealosuchipus hanksi igen. et isp. nov., is based on a partly complete trackway having fore- and hind-footprints as well as body marks preserved in hyporelief. These tracks are directly associated with numerous body fossils including articulated bones which provide strong implications for their probable origin. The second specimen, Koupichnium pentapodus isp. nov., is founded on a trackway of a small invertebrate in which a series of five pairs of footprints are arranged along a midline drag mark which is continuous throughout the length of its trackway. This trackway shares features with other fossils as well as living arthropod trackways in which four small feet and a larger posterior hind “pusher” foot are present. The two described new ichnotaxa represent the first recognized tracks from the Wannagan Creek local fauna.     

Sauropod Trackway Reflecting an Unusual Walking Pattern from the Early Cretaceous of Shandong Province,China

The trackway of a quadrupedal dinosaur from the Early Cretaceous (Albian) Qingquan tracksite (Tancheng, Shandong Province) is redescribed, and the trackmaker is identified as a sauropod. The trackway makes a slight turn towards the northwest and is characterized by an extremely narrow gauge pattern and an unusual configuration, i.e., a conspicuous difference between the position of the left and right manus tracks with respect to the position of the preceding pes track. Left manus tracks are located on the inside of the trackway, very close (and sometimes even in connection) to the opposite right pes tracks. So far, the Qingquan trackway is possibly the only extremely narrow-gauge sauropod trackway known from China. However, it is not clear to what extent this extremely narrow gauge pattern is related to the turning or a special behavior, or even linked to an injury (“limping trackway”). We tentatively attribute the Qingquan trackway to cf. Parabrontopodus, even though it has a rather low heteropody that is significantly lower than in Parabrontopodus and not typical for narrow-gauge sauropod trackways, but occurs in the wide-gauge ichnotaxon Brontopodus. Because of this discrepancy, the Qingquan trackway cannot readily be attributed to a more basal sauropod, which is generally considered the producer of narrow-gauge trackways. Therefore, the identification of a distinct sauropod group is not possible presently. The only skeletal remains of sauropods from the Lower Cretaceous of Shandong Province belong to the large titanosauriform, Euhelopus zdanskyi.     

Molecular phylogeny of extant horseshoe crabs (Xiphosura, Limulidae) indicates Paleogene diversification of Asian species

Horseshoe crabs are marine invertebrates well known for their exceptionally low rates of diversification during their entire evolutionary history. Despite the low species diversity in the group, the phylogenetic relationships among the extant species, especially among the three Asian species are still unresolved. Here we apply a new set of molecular genetic data in combination with a wide geographic sampling of the intra-specific diversity to reinvestigate the evolutionary history among the four living limulid xiphosurans. Our analysis of the intraspecific diversity reveals low levels of connectivity among Carcinoscorpius rotundicauda lineages, which can be explained by the estuarine-bound ecology of this species. Moreover, a clear genetic break across the Thai-Malay Peninsula suggests the presence of cryptic species in C. rotundicauda. The limulid phylogeny finds strong support for a monophyletic genus Tachypleus and a diversification of the three Asian species during the Paleogene period, with speciation events well separated in time by several million years. The tree topology suggests that the three Asian species originated in central South East Asia from a marine stem group that inhabited the shallow coastal waters between the Andaman Sea, Vietnam, and Borneo. In this region C. rotundicauda probably separated from the Tachypleus stem group by invading estuarine habitats, while Tachypleus tridentatus most likely migrated northeast along the Southern coast of China and towards Japan.     

A Temnospondyl Trackway from the Early Mesozoic of Western Gondwana and Its Implications for Basal Tetrapod Locomotion

Background

Temnospondyls are one of the earliest radiations of limbed vertebrates. Skeletal remains of more than 190 genera have been identified from late Paleozoic and early Mesozoic rocks. Paleozoic temnospondyls comprise mainly small to medium sized forms of diverse habits ranging from fully aquatic to fully terrestrial. Accordingly, their ichnological record includes tracks described from many Laurasian localities. Mesozoic temnospondyls, in contrast, include mostly medium to large aquatic or semi-aquatic forms. Exceedingly few fossil tracks or trackways have been attributed to Mesozoic temnospondyls, and as a consequence very little is known of their locomotor capabilities on land.

Methodology/Principal Findings

We report a ca. 200 Ma trackway, Episcopopus ventrosus, from Lesotho, southern Africa that was made by a 3.5 m-long animal. This relatively long trackway records the trackmaker dragging its body along a wet substrate using only the tips of its digits, which in the manus left characteristic drag marks. Based on detailed mapping, casting, and laser scanning of the best-preserved part of the trackway, we identified synapomorphies (e.g., tetradactyl manus, pentadactyl pes) and symplesiomorphies (e.g., absence of claws) in the Episcopopus trackway that indicate a temnospondyl trackmaker.

Conclusions/Significance

Our analysis shows that the Episcopopus trackmaker progressed with a sprawling posture, using a lateral-sequence walk. Its forelimbs were the major propulsive elements and there was little lateral bending of the trunk. We suggest this locomotor style, which differs dramatically from the hindlimb-driven locomotion of salamanders and other extant terrestrial tetrapods can be explained by the forwardly shifted center of mass resulting from the relatively large heads and heavily pectoral girdles of temnospondyls.     

The matrix affects trackway corridor suitability for an arenicolous specialist beetle

In conserving regional insect diversity dispersal corridors are advocated to counteract fragmentation and for resilience to climate change. However, influences of corridor design and management on their function are poorly understood. Effects of contrasting matrix structure on the suitability and function of trackways as corridors for dispersal of an arenicolous carabid beetle, Harpalus rufipalpis (Sturm), was studied within a plantation landscape using mark-release-recapture. A total of 1,120 marked H. rufipalpis were released into four trackways: two “open” trackways surrounded by pine plantations aged 13–16 years and two “shaded” trackways surrounded by plantations aged 26–37 years. Dispersal was monitored by a grid of pitfall transects placed across trackways at intervals of four meters, extending 44 m north and south of the release point. Numbers of resident and marked recaptured H. rufipalpis, their average daily movement rates and numbers of recaptures in the north and south direction were compared between open and shaded trackways using 238 recaptures. The surrounding matrix affected trackway suitability with greater abundance of resident beetles found in open trackways; however H. rufipalpis was also naturally present in shaded trackways. H. rufipalpis were more active in low quality shaded corridors as inferred from the greater number of recaptures and from greater daily movement rates. Corridor edge permeability differed between trackway types, with more individuals leaving the corridor to enter the matrix in the less suitable shaded trackways. Thus matrix type affected the potential habitat suitability and conduit function of trackway corridors.     

Trackway Ratio: A New Look at Trackway Gauge in the Analysis of Quadrupedal Dinosaur Trackways and its Implications for Ichnotaxonomy

A new parameter, the Trackway Ratio (TR), is proposed to supplement the previously used trackway gauge to describe and quantify the relative width of trackways in dinosaur quadrupedal gaits. It is expressed as the ratio of the width of the tracks relative to the total width of the trackway (both measured perpendicular to the long axis of the trackway). The ratio may be used with either pes (PTR) or manus (MTR) tracks. The PTR range of values for wide-, medium- and narrow-gauge trackways of previous authors are provisionally suggested to be ≤35%, 36–49% and ≥50%, respectively. The application of such a ratio would permit a more consistent ichnotaxonomy to be adopted where both track morphology and trackway parameters are used to define ichnotaxa.

Determination of the TR, as well as other parameters, will be affected by track preservation quality. Recent experiments on track simulation in the laboratory have shed further light on observations made in the field concerning the value of track measurements (in particular track length and width) recorded from below the surface on which the maker was moving. Experimental track simulations in the laboratory have shown that the dimensions of transmitted tracks preserved below the surface on which the foot was impressed may vary from 65% to 135% of the true dimensions of the indenter. Two case studies are presented that quantify the errors that may be made on calculating TR and the size, gait and speed of the maker, from trackways if the preservation of the tracks are not fully understood.

It is shown that in individual trackways the PTR may vary along the length of the trackway; so that part of the trackway may be classified as wide-gauge and other parts medium-gauge. There is a relationship between variation in PTR and that of pace angulation along the length of a single trackway. An analysis of 42 trackways, principally sauropod, shows a temporal distribution that does not agree closely with previous suggestions relating to narrow- and wide-gauge trackways.     

The Smallest Known Tetrapod Footprints: Batrachichnus Salamandroides from the Carboniferous of Joggins,Nova Scotia,Canada

A new specimen of Batrachichnus salamandroides from the classic Carboniferous section at Joggins, Nova Scotia, is the smallest set of tetrapod footprints known in the fossil record. The trackmaker was a juvenile, quadrupedal temnospondyl or microsaur with a trunk length of 3.55 mm and an estimated body length of 8 mm (skull, presacral vertebrae, and caudal vertebrae). The 48 mm-long trackway preserves a high degree of extramorphological variation along its course, including a gait change associated with a change in direction along with an increased stride and pace, and the appearance of overstepped imprints, in the latter portion of the trackway. These morphological changes suggest the tetrapod changed from a walking gait to a running gait.     

Weinbergina,a xiphosuran arthropod from the devonian hunsrück slate

Weinbergina is the first synziphosurid in which ventral appendages have been found. It is so far unique among chelicerates in having six pairs of prosomal legs in addition to the chelicerae. This indicates that the pregeni tal segment with the last pair of walking legs, corresponding to the chilaria ofLimulus, must be counted with the prosoma. The first interpretation of the opisthosomal appendages is given. They appear to be plate-like and to combine the presence of lamellar gills of limulid type with flattened spines (so called gill filaments) of trilobitomorph type.Weinbergina apparently was adapted for a life on soft substrate but not for burrowing.     

The oldest illustration of Chinese crinoid calyx: Annotated translation of “Cupressocrinus abbreviatus” reported by Fritz Frech in 1911

The early history on the discovery of the first Chinese crinoid calyx of “Cupressocrinus abbreviatus” (now Halocrinites schlotheimii Steininger, 1831) remains unclear. The first record of “C. abbreviatus” was reported by Fritz Frech in 1911. It was included in the fifth and the last volume of the series titled China by the German traveler and explorer Ferdinand Freiherr von Richthofen. The cover page, title page, and prologue are informative; thus, they are explained and translated in detail. Richthofen's specimen is still the oldest documented cupressocrinitid calyx known in China today. Discovery of a second cupressocrinitid specimen confirms the existence of this family in China. Current taxonomic positions of the Chinese specimens are discussed.     

A new species of <Emphasis Type="Italic">Cosmospora</Emphasis> and the first record of sexual state of <Emphasis Type="Italic">C. lavitskiae</Emphasis>

A new fungicolous species, Cosmospora inonoticola, is described and illustrated based on a specimen collected from northeast China. It is characterized by the occurrence of fruitbodies of Inonotus sp.; perithecia nonstromatic, subglobose to pyriform, not collapsing when dry; clavate asci containing (3–)6(?8) spores; ascospores ellipsoidal to broadly ellipsoidal, pale brown, finely warted, bicellular, conspicuously constricted at septum; and producing a verticillium-like asexual state. A multi-locus analysis of the combined ITS, rpb1 and tub sequences confirmed its taxonomic position, and revealed the distinction from its morphologically similar species including the type species, C. coccinea, which occurs also on Inonotus. A specimen with sexual state of C. lavitskiae is reported for the first time, and a reference specimen is indicated.     

Probable crocodilian tracks and traces from the Morrison Formation (Upper Jurassic) of eastern Utah

A tetradactyl pes impression and tridactyl manus impression are described as the type specimen of Hatcherichnus sanjuanensis ichnogen. et ichnosp. nov., a probable large crocodilian ichnite from the Salt Wash Member of the Upper Jurassic Morrison Formation in eastern Utah. A similar pes track from the Morrison Formation at Garden Park, Colorado, may also belong to this ichnogenus. The type specimen from Utah consists of plaster replicas of natural casts of a left pes impression and a left manus impression. Associated with the type specimen were possible tail and body drag impressions. The tracks do not appear to be part of a walking trackway and may be swim tracks associated with an animal in shallow water. The tracks occur at a visible contact between slightly fining‐upward channel sandstone units.     

Early Cretaceous pterosaur tracks from a “buried” dinosaur tracksite in Shandong Province,China

Here we describe the pterosaur and tridactyl dinosaur footprint assemblage from a new tracksite in the Early Cretaceous Qugezhuang Formation near the Wenxiyuan Community in Jimo County-level City, Qingdao City, Shandong Province, East China. The construction of a community building has, since the discovery, covered the majority of tracks, but a few specimens on abandoned building stones constitute the first pterosaur track record in eastern China. The pterosaur tracks are assigned to Pteraichnus isp. and were probably made by a small to medium-sized pterodactyloid. The new pterosaur trackway contributes to the growing database of pterosaurian ichnites in Asia. The Wenxiyuan tridactyl dinosaur tracks are morphologically similar to those of theropods, but they are too poorly preserved to be referred to any particular ichnotaxon.     

A new troodontid theropod, Talos sampsoni gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America

Background

Troodontids are a predominantly small-bodied group of feathered theropod dinosaurs notable for their close evolutionary relationship with Avialae. Despite a diverse Asian representation with remarkable growth in recent years, the North American record of the clade remains poor, with only one controversial species—Troodon formosus—presently known from substantial skeletal remains.

Methodology/Principal Findings

Here we report a gracile new troodontid theropod—Talos sampsoni gen. et sp. nov.—from the Upper Cretaceous Kaiparowits Formation, Utah, USA, representing one of the most complete troodontid skeletons described from North America to date. Histological assessment of the holotype specimen indicates that the adult body size of Talos was notably smaller than that of the contemporary genus Troodon. Phylogenetic analysis recovers Talos as a member of a derived, latest Cretaceous subclade, minimally containing Troodon, Saurornithoides, and Zanabazar. MicroCT scans reveal extreme pathological remodeling on pedal phalanx II-1 of the holotype specimen likely resulting from physical trauma and subsequent infectious processes.

Conclusion/Significance

Talos sampsoni adds to the singularity of the Kaiparowits Formation dinosaur fauna, which is represented by at least 10 previously unrecognized species including the recently named ceratopsids Utahceratops and Kosmoceratops, the hadrosaurine Gryposaurus monumentensis, the tyrannosaurid Teratophoneus, and the oviraptorosaurian Hagryphus. The presence of a distinct troodontid taxon in the Kaiparowits Formation supports the hypothesis that late Campanian dinosaurs of the Western Interior Basin exhibited restricted geographic ranges and suggests that the taxonomic diversity of Late Cretaceous troodontids from North America is currently underestimated. An apparent traumatic injury to the foot of Talos with evidence of subsequent healing sheds new light on the paleobiology of deinonychosaurians by bolstering functional interpretations of prey grappling and/or intraspecific combat for the second pedal digit, and supporting trackway evidence indicating a minimal role in weight bearing.     

New material of Xyelydidae (Hymenoptera) from the Lower Cretaceous Yixian Formation of China

Chifengilyda robusta, a new extinct sawfly genus and new species assigned to Xyelidae, is described and figured here based on one fossil specimen from the Lower Cretaceous Yixian Formation of Ningcheng in Inner Mongolia, China. Chifengilyda robusta n. gen. n. sp. differs from other xyelydids in having a forewing with pterostigma completely sclerotized, Sc closer to C, Sc1 about 3 times as long as Sc2, Sc1 intersecting C far beyond Rs base, 2r-m postfurcal and cell 1mcu relatively large. This new taxon further enriches the diversity of Xyelydidae in the Early Cretaceous, and even enhances our understanding of the evolution and inter-genera and interspecies relationships of this family.     

Large theropod trackway from the Lower Jurassic Zhenzhuchong Formation of Weiyuan County,Sichuan Province,China: Review,new observations and special preservation

The well-preserved theropod track Weiyuanpus zigongensis, recently assigned to Eubrontes zigongensis, was not described in exhaustive detail at the time of its original discovery in 2007. Among the morphological details not described was an antero-medially directed hallux seen in five of the six tracks that make up the type trackway. Hallux traces are only rarely reported in large Lower Jurassic theropod tracks such as Eubrontes and Gigandipus, and their presence or absence may be the result of one or both of two factors: track depth and/or differences in hallux configuration in the trackmakers. Here we argue that E. zigongensis is one of the best preserved examples of a eubrontid track, which can be morphologically distinguished from other Eubrontes ichnospecies by the presence of well-defined hallux traces.     

Reanalysis of Wupus agilis (Early Cretaceous) of Chongqing,China as a Large Avian Trace: Differentiating between Large Bird and Small Non-Avian Theropod Tracks

Trace fossils provide the only records of Early Cretaceous birds from many parts of the world. The identification of traces from large avian track-makers is made difficult given their overall similarity in size and tridactyly in comparison with traces of small non-avian theropods. Reanalysis of Wupus agilis from the Early Cretaceous (Aptian-Albian) Jiaguan Formation, one of a small but growing number of known avian-pterosaur track assemblages, of southeast China determines that these are the traces of a large avian track-maker, analogous to extant herons. Wupus, originally identified as the trace of a small non-avian theropod track-maker, is therefore similar in both footprint and trackway characteristics to the Early Cretaceous (Albian) large avian trace Limiavipes curriei from western Canada, and Wupus is reassigned to the ichnofamily Limiavipedidae. The reanalysis of Wupus reveals that it and Limiavipes are distinct from similar traces of small to medium-sized non-avian theropods (Irenichnites, Columbosauripus, Magnoavipes) based on their relatively large footprint length to pace length ratio and higher mean footprint splay, and that Wupus shares enough characters with Limiavipes to be reassigned to the ichnofamily Limiavipedidae. The ability to discern traces of large avians from those of small non-avian theropods provides more data on the diversity of Early Cretaceous birds. This analysis reveals that, despite the current lack of body fossils, large wading birds were globally distributed in both Laurasia and Gondwana during the Early Cretaceous.