Left Manus Research Articles

A TEMNOSPONDYL HANDPRINT FROM THE UPPER PALEOZOIC OF THE MATZITZI FORMATION, MEXICO

We report a natural cast of the left manus of an indeterminate temnospondyl, found in an outcrop of the Matzitzi Formation (Upper Permian) in the northwestern region of the State of Oaxaca, Mexico. This ichnite is the first record of temnospondyls for the country, as well as the southernmost record of this group in North America; additionally, this is the oldest known record of a tetrapod in Mexico.

New insights into the fossil record of the turtle genus Chelus Duméril, 1806 including new specimens with information on cervicals and limb bones

Matamata turtles (Chelus Duméril, 1806) are composed of two extant species, Chelus fimbriata ­Schneider, 1783 and Chelus orinocensis Vargas-Ramírez, Caballero, Morales-Betancourt, Lasso, Amaya, Martínez, Silva-Viana, Vogt, Farias, Hrbek, Campbell & Fritz, 2020, inhabitants of the main freshwater drainages of northern South America. The systematics and palaeobiogeography of Chelus is still unresolved. Here, we describe several new fossil specimens from the Late Miocene of Urumaco (Venezuela) and Tatacoa (Colombia). The fossils are mostly complete, articulated shells that allow reestablishing validity of two extinct taxa, Chelus colombiana Wood, 1976 and Chelus lewisi Wood, 1976. One of the specimens of C. lewisi from Urumaco represents the first record within the genus for which autopodial bones (a left manus) and additional limb bones are preserved together with ashell, demonstrating evolutionary conservatism in limb anatomy for the genus. The specimen comes from the Socorro Formation, representing the earliest so far known record of Chelus for the Urumaco sequence. Additionally, one specimen from Tatacoa is the first fossil for which cervical and pectoral girdle elements are preserved. Phylogenetic analysis supports the existence of two separate clades inside of Chelus, one formed by the extinct species and the other by the extant ones.

Is Docetaxel the Main Therapy for Lung Metastasis in Granular Cell Tumors?

Introduction: A granular cell tumor is a rare neoplasm originating from mesenchymal tissue. Malignant granular cell tumors have a poor prognosis. The lung is one of the target organs for metastatic malignant granular cell tumors. The number of rare cases makes managing metastatic malignant granular cell tumors unknown. Case: A 19-year-old male complained of shortness of breath for two months. A liver nodule biopsy revealed poorly differentiated carcinoma metastases. Histopathology of the left manus and frontal masses found granular cell tumors—negative immunohistochemistry on S-100 and myogenin. Ki-67 obtained a value of 5%. An X-ray and contrast multislice computerized tomography (MSCT) scan showed multiple metastatic nodules. Right bronchial biopsy forceps revealed a metastatic granular cell tumor. The patient was given docetaxel for six cycles. During the post-administration of docetaxel, the patient experienced clinical and radiological improvement. Conclusion: Until 2016, only three case reports of S-100 negative granular cell tumors existed. A negative S-100 test does not rule out the diagnosis of granular cell tumors. Malignant lesions are more common in males, as in this case. The number of rare cases means that management cannot be determined. Reports of similar cases show patients surviving up to 11 years with docetaxel administration. The patient in this study has survived for one year and is complaint-free.

Unexpected record of the aquatic sloth Thalassocnus (Mammalia, Xenarthra, Folivora) in the upper Neogene of the Puna (Jujuy, Argentina)

ABSTRACT Xenarthra are, very probably, the most basally branching clade among Placentalia, and the result of the so-called “Splendid Isolation” of South America. Although this is the only endemic clade with living representatives, its current diversity is very poor compared with that achieved during most of the Cenozoic. One particular clade, Folivora (living and fossil sloths), includes one of the most enigmatic animals, Thalassocnus, the only genus of the subfamily Thalassocninae. It was originally interpreted as an aquatic sloth taking into account the previous records, which are limited to coastal areas of the latest Miocene and Pliocene of Peru and Chile. Here we present the first record of Thalassocnus from Argentina, which in turn represents the first finding of the genus in a continental sequence. The materials (JUY-P-0180, radius, ulna and part of the articulated left manus) were exhumed from the upper member of the Tafna Formation (Late Miocene–Pliocene) in the eastern Puna (Jujuy Province), Argentina. In agreement with our comparative study, the cladistic analysis corroborates its identification as belonging to the genus Thalassocnus, being placed in a relatively basal location. This finding is of paleobiogeographic and paleoenvironmental significance, due to its location, more than 1171 km away from the Peruvian locality (Sacaco) and more than 750 km from the nearest ones in Chile (Caldera). This extends the geographic range from 76°W to 65°53′W, and from typical littoral environments, to clearly more terrestrial ones. The evolutionary and paleobiogeographic history of Thalassocnus is more complex than previously interpreted.

A new pseudosuchian archosaur, Mambawakale ruhuhu gen. et sp. nov., from the Middle Triassic Manda Beds of Tanzania.

The Manda Beds of southwest Tanzania have yielded key insights into the early evolutionary radiation of archosaurian reptiles. Many key archosaur specimens were collected from the Manda Beds in the 1930s and 1960s, but until recently, few of these had been formally published. Here, we describe an archosaur specimen collected in 1963 which has previously been referred to informally as Pallisteria angustimentum. We recognize this specimen as the type of a new taxon, Mambawakale ruhuhu gen. et sp. nov. The holotype and only known specimen of M. ruhuhu comprises a partial skull of large size (greater than 75 cm inferred length), lower jaws and fragments of the postcranium, including three anterior cervical vertebrae and a nearly complete left manus. Mambawakale ruhuhu is characterized by several cranial autapomorphies that allow it to be distinguished with confidence from all other Manda Beds archosaurs, with the possible exception of Stagonosuchus nyassicus for which comparisons are highly constrained due to very limited overlapping material. Phylogenetic analysis suggests that M. ruhuhu is an early diverging pseudosuchian, but more precise resolution is hampered by missing data. Mambawakale ruhuhu is one of the largest known pseudosuchians recovered to date from the Middle Triassic.

New manual unguals of Trierarchuncus prairiensis from the Hell Creek Formation, Montana, and the ontogenetic development of the functional alvarezsaurid hand claw

The Alvarezsauridae comprise a clade of small-bodied theropod dinosaurs with highly-specialized skeletal adaptations, primarily reduced but proportionately robust forelimbs which have been hypothesized as relating to an insectivorous ecology. Alvarezsaurids are known predominantly from Mongolia, China, and South America, with a comparatively sparse North American record, where alvarezsaurid remains are among the most rarely recovered vertebrate fossils from the Upper Cretaceous Western Interior. North American alvarezsaurids include Albertonykus borealis from the lower Maastrichtian Horseshoe Canyon Formation of Alberta, Canada, known from a partial skeleton and additional isolated remains, and the recently named Trierarchuncus prairiensis from the upper Maastrichtian Hell Creek Formation of eastern Montana, USA, known previously from isolated specimens, including three manual D-I unguals, a partial radius, and a partial metatarsal III. Here we describe two new manual D-I unguals referable to the alvarezsaurid Trierarchuncus from the Hell Creek Formation of eastern Montana, USA. These new unguals contribute additional detail to the currently known ontogenetic series of Trierarchuncus manual D-I unguals and indicate the sequence and degree of change that occurred through growth within these alvarezsaurid hand claws. These changes appear to be modifications and reinforcement related to stresses induced from the hypothesized ecology of alvarezsaurids as insectivores which would tear apart substrates in search of insect prey, and as such can be characterized as ecologically-driven ontogenetic changes. Additionally, we demonstrate morphological indicators for determining whether isolated alvarezsaurid manual D-I unguals pertain to the right or left manus.

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

ABSTRACTThe 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.

A diverse saurischian (theropod–sauropod) dominated footprint assemblage from the Lower Cretaceous Jiaguan Formation in the Sichuan Basin, southwestern China: A new ornithischian ichnotaxon, pterosaur tracks and an unusual sauropod walking pattern

A sample of fallen blocks of fluvial sandstone from the Lower Cretaceous Jiaguan Formation of Sichuan Province yielded an assemblage of dinosaur and pterosaur tracks preserved as natural impressions and casts. Collectively the assemblage reveals 132 tracks representing at least 30 trackways of tridactyl and didactyl theropods, sauropods, ornithopods and pterosaurs. Ichnotaxonomically, the trackways of small tridactyl theropods (pes lengths 7–18 cm) are indeterminable, whereas the trackway of a small didactyl dromaeosaur (pes length up to 7.5 cm) is tentatively assigned to cf. Velociraptorichnus. The sauropod trackways are assigned to cf. Brontopodus based on the medium to nearly wide-gauge pattern. Other characteristics are the U-shaped manus and strong heteropody. One sauropod trackway shows a peculiar pattern with a lack of left manus imprints, and an unusual position and rotation of right manus imprints. Different scenarios and explanations for this phenomenon are discussed. Ornithopod trackways are the most abundant in the sample and characterized by pes imprints of a small biped that are assigned here to the new ichnospecies Caririchnium liucixini. It is characterized by an unusual broad shape and weak mesaxony. Bivariate analysis of different Caririchnium ichnospecies reveals increasing mesaxony toward the larger forms, a trend that is the reverse of typical theropod ichnotaxa, where large imprints have weak mesaxony. Three isolated, small pterosaur tracks (two manus, one pes) are visible on a single surface. They show strong similarities to the widespread ichnogenus Pteraichnus. This is the ninth report of tetrapod tracks from the Jiaguan Formation in recent years and represents one of the most diverse assemblages recorded to date. It is also rare evidence of typical didactyl dromaeosaur tracks and the co-occurrence of sauropod and ornithopod tracks in a fluvial depositional environment representing arid climate conditions.

First occurrence of carnivore footprint with hyaenid affinities from the Late Miocene of Crete (Greece)

Nine terrestrial mammal localities of Miocene age based on body fossils have been reported from the island of Crete to date. A new locality where footprints of terrestrial mammals were exposed has recently been discovered in western Crete. Platýlakkos, the locality, is situated near the village Vouves, west of the city of Chania. The ichnofossils come from lacustrine deposits that belong to the Chatzi Formation. The most impressive finding is a clearly defined footprint that might be referred to a large-sized hyaenid. The footprint impression, a convex hyporelief on a sandstone slab, is a natural cast of a left manus where the traces of the interdigital pad and all four digital pads, as well as their respective claw marks- are clearly visible. Based on nearby marine deposits of the Chatzi Formation, the age of the fossiliferous layer with the footprints can be considered to be early to middle Turolian (MN11-MN12) in terms of mammalian biochronology. To date, there is no certain record of Miocene large-sized hyaenid footprints worldwide, and thus this isolated footprint might belong to a new ichno- taxon. However, in the absence of a trackway, the erection of a new ichnotaxon is avoided. The Platýlakkos findings are the first recorded case of fossil land mammal footprints from the Neogene of Crete, and Greece in general. They further the evidence for the presence of well-established terrestrial environments and faunas in the area of Crete during the Late Miocene.

Miocene Mammalian footprints in coprolites from Lisbon, Portugal

For the first time, at least for the Lisbon Miocene series, uncommon ichnologic evidence has been recognized, i.e. mammalian footprints in coprolites. Three coprolites were recorded in three successive stratigraphic units, IVb and Va2 from the Lower Miocene to Vb from the early Middle Miocene. The largest, tridactyl footprint can be ascribed to a right foot of a rhinoceros. Size excludes all the rhinocerotids known from the Vb unit except Hispanotherium matritensis. A smaller coprolite (Va2 unit) shows a tridactyl, left foot impression of a perissodactyl. It is clearly too small for a rhinoceros, even for a young one. It seems to have been made by an Anchitherium Equid. The pes had a plantar pad as still found in the Mesohippus–Anchitherium lineage but not in more advanced Equids. Both tridactyl imprints may have been produced by the coprolite-makers. A large coprolite (IVb unit) that may have been produced by Brachyodus onoideus shows a few didactyl imprints. An artiodactyl trampled the dung with hoofs sliding on its surface and producing two incomplete imprints. It also trampled the dung in a more stable position, producing the best imprint, whose structure indicates it was produced by the left manus. The lack of lateral toe marks excludes suids (and Brachyodus, also because its size is too much small). It is from a small-sized ruminant, most probably a cervid, genus Procervulus. In all cases, defecation occurred on dry land, albeit in eventually or seasonally flooded areas near a river.

A new Oviraptorosaur (Theropoda, Maniraptora) from the Late Cretaceous (Campanian) of Utah

ABSTRACT Recent field expeditions to Upper Cretaceous deposits within Grand Staircase-Escalante National Monument, southern Utah, have revealed a diverse dinosaurian fauna that includes a previously unknown oviraptorosaur theropod. Represented by a single partial specimen consisting of manal and pedal elements, this new taxon, Hagryphus giganteus, gen. et. sp. nov., is estimated to be 30–40% larger than the coeval oviraptorosaur Chirostenotes. The holotype consists of a nearly complete, articulated left manus, a partial, articulated pedal digit II, and a series of fragmentary pedal phalanges and distal metatarsals. Several autapomorphies are present in the manus, related primarily to proportional differences in metacarpals and phalanges. Previous finds of North American oviraptorosaurs have been restricted to Alberta, Montana, and South Dakota. The discovery of this new specimen from southern Utah greatly expands the known geographic distribution of these theropods, nearly doubling the previously documented range of North American oviraptorosaurs.

A new species of Archaeohippus (Mammalia, Equidae) from the Arikareean of central Florida

ABSTRACT The origin of the small, Miocene horse Archaeohippus is poorly known. A recently collected specimen from the late Oligocene or earliest Miocene (Arikareean) of Florida represents Archaeohippus mannulus, sp. nov. It includes a complete upper dentition, a partial left dentary with dp1–m3, and most of the right and left manus. It is the most nearly complete skeleton of an Arikareean Archaeohippus. Distinguishing characteristics of A. mannulus include: on upper P2–P3, anteroposteriorly narrow hypocone with a pronounced medivallum ridge originating on the metaloph; lower cheek teeth with a mediolaterally broad and flat hypoconulid; and extremely small body size with very gracile limb elements. Body mass of this individual is estimated at 10 kg. The revised generic diagnosis includes derived features of Archaeohippus relative to Miohippus and Anchitherium such as crochets on upper cheek teeth and reduced tridactyly, which link it with Parahippus, merychippine-grade equids, hipparionines, and equines.

Microsurgical Procedure for Feather Cyst Removal in a Citron-crested Cockatoo (Cacatua sulphurea citrinocristata)

A citron-crested cockatoo (Cacatua sulphurea citrinocristata) was referred for a recurring feather cyst involving the dorsal major covert overlying primary feather VIII on the left manus. Surgical removal of the affected follicle was successful using a surgical retractor system, an operating microscope, a bipolar radiosurgical unit, and microsurgical instrumentation. The cyst has not recurred during the 2 years following surgery, and no new cysts have formed on adjacent feathers. Previously published reports suggest that feather cyst removal is unrewarding because cysts frequently recur after lancing, curettage, or fulguration. This report provides a description of complete feather follicle removal that may be a superior method for handling cystic follicles.

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.