|The part and counterpart of University of Minnesota Paleontology Collections 4090, holotype of graptolite Dictyonema minnesotense Ruedemann 1933, collected from the St. Lawrence Formation at a no-longer extant site in Afton, Minnesota, now within Saint Croix National Scenic Riverway.|
A new insect from Florissant
That's a useful segue into our first paper, Makarkin (2017) on a new genus of neuropteran from Florissant, Colorado. Neuropterans, if you haven't had the pleasure of being introduced, are the group of insects that includes lacewings and antlions. Markarkin's fossil is actually an old specimen, probably collected by T. D. A. Cockerell, which is pretty good pedigree for a Florissant fossil. There's just so many arthropod fossils from Florissant and such great natural diversity, that even with more than a century of research, there are still more forms to be described. The holotype is University of Colorado-Boulder specimen UCM 85899, which is nearly complete but kind of vague in details, except for one well-preserved wing. It is listed as coming from one of Cockerell's localities that can be placed in Florissant Fossil Beds National Monument, per my own research on the subject. It has been named Pseudosmylidia relicta. P. relicta was an osmyslid (a giant lacewing), and appears to have been unusually "old-fashioned" for an Eocene osmylid, differing from the other two species of osmylid known from the Florissant Formation.
Tracks at Dinosaur National Monument
This one's a slight bit of a cheat, because the main tracksite featured in this paper by Engelmann and Chure is from outside of Dinosaur National Monument, but there is indeed a tracksite from the monument included. (Incidentally, the monument may be most famous for Upper Jurassic dinosaurs, but it has an outstanding and well-rounded fossil record in general, particularly from the Mississippian through the Cretaceous.) Here's the set-up: almost all known fossil vertebrate tracks in eolian dune settings, Paleozoic to Pleistocene, are from animals going upslope. Proposals put forward to explain this include animals going downslope inadvertently destroy their tracks, and behavioral possibilities such as animals going downslope by different routes than going upslope. Engelmann and Chure document a tracksite from outside the monument that includes four examples of Brasilichnium trackways going upslope (Brasilichnium tracks are thought to have come from small tritylodonts, synapsids that are almost as close as you can get to being mammals without being mammals). These tracks were compared with a Brasilichnium trackway from Dinosaur National Monument that shows an animal going more or less across a slope right to left, ascending just a bit. The tracks from the left side of the body are much larger than those on the right side, which makes sense because most of the body weight would have been on the left limbs.
Dung from Bechan Cave
Last year I wrote a short feature on Rampart Cave in Grand Canyon National Park for National Fossil Day (archival link here). The cave's great claim to fame is (well, was) its thick deposits of ground sloth dung. Rampart Cave is not the only dung cave in existence. Another such cave, known as Bechan Cave, has also attracted a fair amount of attention. Bechan Cave, located in Glen Canyon National Recreation Area, received its name from the dung, Bechan meaning more or less "big feces" in Navajo. Accumulations of large plant-rich plops in the cave have often been attributed to mammoths, although mastodons and large sloths could also have produced them based on size. Karpinski et al. (2017 in press) have addressed the question of "who dung it" through DNA. Most DNA found in droppings comes from various microorganisms, but some comes from the producer. Karpinski et al. took samples from a Bechan Cave dung bolus and found the samples to plot with mammoths instead of mastodons or sloths. Furthermore, the DNA indicated the producer was within a group that contains all known Columbian mammoth genetic diversity (although I'd be remiss if I didn't mention that mammoth taxonomy is a mammoth headache).
Small shelly fossils in Death Valley
Finally, Wotte and Sundberg have an article in press describing small shelly fossils from the California–Nevada area, including Echo Canyon in Death Valley National Park. "Small shelly fossils" is kind of a catch-all for various skeletal bits pertaining to organisms that lived on either immediate side of the Precambrian–Cambrian boundary, and as such doesn't necessarily mean that a fossil is small or a shell. Think of the term as a nickname instead of a classification. For example, the Echo Canyon "small shelly fossils" include hyoliths, Hyolithellus, chancelloriids, and bits of echinoderms. Hyoliths, as we learned recently, were related to brachiopods. Hyolithellus is this conical tubular thingie that was once thought to be a hyolith, but is now thought to be more wormy in affiliation. Chancelloriids were kind of like sponges, being sacks-like organisms with a framework of spicule bits called sclerites. Cambrian echinoderms ran the gamut from plated bags that looked vaguely like fingerprints (Helicoplacus) to early experiments with the stalked lifestyle (eocrinoids). These fossils show the early diversification of animals with hard body parts in the Cambrian of the Great Basin.
Engelmann, G. F., and D. J. Chure. 2017. Morphology and sediment deformation of downslope Brasilichnium trackways on a dune slipface in the Nugget Sandstone of northeastern Utah, USA. Palaeontologia Electronica 20.2.22A:1–21.
Karpinski, E., J. I. Mead, and H. N. Poinar. 2017. Molecular identification of paleofeces from Bechan Cave, southeastern Utah, USA. Quaternary International in press.
Makarkin, V. N. 2017. A remarkable new genus of Protosmylinae (Neuroptera: Osmylidae) from late Eocene Florissant, Colorado. Zootaxa 4268(4):581–587.
Ruedemann, R. 1933. The Cambrian of the upper Mississippi Valley, part III, Graptolitoidea. Milwaukee Public Museum Bulletin 12(3):307–348.
Wotte, T., and F. A. Sundberg. 2017. Small shelly fossils from the Montezuman–Delamaran of the Great Basin in Nevada and California. Journal of Paleontology advance online.