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We redescribe the morphology of Yohoia tenuis (Chelicerata sensu lato) from the Cambrian Burgess Shale Lagerstätte. The morphology of the most anterior, prominent, so-called great appendage changes throughout ontogeny. While its principal morphology remains unaltered, the length ratios of certain parts of the great appendage change significantly. Furthermore, it possesses a special jack-knifing mechanism, i.e. an elbow joint: the articulation between the distal one of the two peduncle elements and the most proximal of the four spine-bearing claw elements.

• Read more about Functional morphology, ontogeny and evolution of mantis shrimp-like predators in the Cambrian

The spine-bearing jawed vertebrates (gnathostomes) assigned to the assemblage ‘Acanthodii’ play a key role in understanding the early evolution of osteichthyans and chondrichthyans. Amongst ‘acanthodians’, the genus Ptomacanthus has played a prominent role owing to its shark-like tooth files. Recently described braincase material from this taxon contrasts strongly with the osteichthyan-like braincase of Acanthodes, the only other ‘acanthodian’ for which this anatomy is well known. This seriously challenges acanthodian monophyly or at least the prevailing interpretation of Acanthodes.

• Read more about A revision of the anatomy of the Early Devonian jawed vertebrate Ptomacanthus anglicus Miles

Four well-preserved beetles, attributed to Eodromeinae within Trachypachidae, are described from the Mesozoic of Inner Mongolia, China. Eodromeus robustus sp. nov., E. daohugouensis sp. nov. and Unda chifengensis sp. nov. are from the Middle Jurassic of Daohugou. The diagnostic characters for the two genera are revised, and all species of these genera are keyed. A new genus and species, Sinodromeus liutiaogouensis gen. nov., sp. nov., is described from the Lower Cretaceous Yixian Formation of Liutiaogou.

• Read more about Mesozoic Trachypachidae (Insecta: Coleoptera) from China

A new type of small, ovoid dinosaur egg, Sankofa pyrenaica oogen. nov. oosp. nov., with a prismatic type eggshell is described from upper Cretaceous (upper Campanian–Maastrichtian) deposits of the Montsec area, South Pyrenean Central Unit, Lleida, Catalonia, Spain. This egg type was sub-vertically laid in only two rich monospecific sites of a single stratigraphic layer from coastal deposits of the Aren Formation, interpreted as an emerged beach ridge of a barrier island – lagoon depositional system.

• Read more about A new peculiar dinosaur egg, Sankofa pyrenaica oogen. nov. oosp. nov. from the Upper Cretaceous coastal deposits of the Aren Formation, south-central Pyrenees, Lleida, Catalonia, Spain

Strata assigned to the Fossil Bluff Group on Alexander Island, Antarctica, contain Aptian to Albian high-latitude echinoderm faunas that lived at palaeolatitudes greater than 60 degrees south. The Pluto Glacier Formation, of essentially Aptian age, yields a deep-water assemblage that includes two ophiuroids, an ophiacanthid and a representative of the ophiolepidid genus Mesophiomusium, both represented by partially articulated specimens.

• Read more about Echinoderm faunas from the Lower Cretaceous (Aptian–Albian) of Alexander Island, Antarctica

Groenlandibelus rosenkrantzi from the Maastrichtian of Greenland has long been thought to constitute an early representative of spirulid coleoids. This study shows that this view must be reassessed, at least in part. A re-investigation of the types and of material recorded subsequently has revealed that none of these specimens is conspecific with the holotype of G. rosenkrantzi. Cyrtobelus birkelundae gen. nov, sp. nov. differs from the type of G. rosenkrantzi in having lower chambers and in lacking an apically elongated sheath.

• Read more about Taxonomy, morphology and phylogeny of Late Cretaceous spirulid coleoids (Cephalopoda) from Greenland and Canada

The middle Devonian (Givetian–Eifelian) pseudoscorpion Dracochela deprehendor Schawaller, Shear and Bonamo is redescribed from the type material and an additional palpal fragment. Dracochela differs from extant pseudoscorpions in having numerous spinules on the leg tarsi, the femur at least as long as the patella on the posterior legs, the stem of the arolia thick, most blades of the serrulae only weakly fused and in lacking a spinneret on the chelicera. The blades of the cheliceral rallum are shown to have been arranged in two rows, as in most Heterosphyronida.

• Read more about Reinterpretation of Dracochela deprehendor (Arachnida: Pseudoscorpiones) as a stem-group pseudoscorpion

The pro-ostracum of the early Sinemurian belemnite Nannobelus from the Belgian Province of Luxembourg is preserved as a thin, irregularly mineralized (phosphatized and pyritized), finely laminated structure, which is situated dorsally between the calcified rostrum and phragmocone.

• Read more about The original composition of the pro-ostracum of an early Sinemurian belemnite from Belgium deduced from mode of fossilization and ultrastructure

Microvertebrate sampling of the Stairway Sandstone (Darriwilian, Middle Ordovician, central Australia) has yielded scales that are chondrichthyan-like in their overall construction, and Tantalepis gatehousei gen. et sp. nov. is erected here to describe these specimens. Tantalepis gatehousei gen. et sp. nov. is the stratigraphically oldest microsquamous taxon described thus far, and the ‘shark-like’ appearance of the scales may extend the chondrichthyan lineage back into the Middle Ordovician.

• Read more about Chondrichthyan-like scales from the Middle Ordovician of Australia

The most common forms of Late Ordovician dalmanellid brachiopods from the Cincinnatian type area, previously treated as either Dalmanella or Onniella, are assigned to Cincinnetina gen. nov. The new genus differs from Dalmanella and Onniella in having a consistently developed primary medial costa in the dorsal valve, a larger cardinal process that tends to develop a trilobed myophore, strongly differentiated fine and coarse punctae, and sparse aditicules.

• Read more about Cincinnetina, a new Late Ordovician dalmanellid brachiopod from the Cincinnati type area, USA: implications for the evolution and palaeogeography of the epicontinental fauna of Laurentia