Mesozoic-Cenozoic crustaceans preserved within echinoid tests and bivalve shells

Associations of crustaceans with echinoids (Echinodermata) and bivalves (Mollusca) are not uncommon in modern oceans. Here we record the occurrence of anomurans, brachyurans and isopods within echinoid tests and bivalve shells from the Middle Jurassic of France, the Upper Jurassic of the Czech Republic, the Eocene of Croatia and the Miocene of Austria. Additionally a new genus and species of fossil cirolanid isopod from the Middle Jurassic of France is described. The present examples are interpreted as crustacean sheltering, probably for safe and undisturbed moulting (ecdysis), within a vacant host test or shell. However, accidental association (washed in) or even food remains cannot be ruled out entirelyWeb of Science90361160

Animal Behavior Frozen in Time: Gregarious Behavior of Early Jurassic Lobsters within an Ammonoid Body Chamber

Direct animal behavior can be inferred from the fossil record only in exceptional circumstances. The exceptional mode of preservation of ammonoid shells in the Posidonia Shale (Lower Jurassic, lower Toarcian) of Dotternhausen in southern Germany, with only the organic periostracum preserved, provides an excellent opportunity to observe the contents of the ammonoid body chamber because this periostracum is translucent. Here, we report upon three delicate lobsters preserved within a compressed ammonoid specimen of Harpoceras falciferum. We attempt to explain this gregarious behavior. The three lobsters were studied using standard microscopy under low angle light. The lobsters belong to the extinct family of the Eryonidae; further identification was not possible. The organic material of the three small lobsters is preserved more than halfway into the ammonoid body chamber. The lobsters are closely spaced and are positioned with their tails oriented toward each other. The specimens are interpreted to represent corpses rather than molts. The lobsters probably sought shelter in preparation for molting or against predators such as fish that were present in Dotternhausen. Alternatively, the soft tissue of the ammonoid may have been a source of food that attracted the lobsters, or it may have served as a long-term residency for the lobsters (inquilinism). The lobsters represent the oldest known example of gregariousness amongst lobsters and decapods in the fossil record. Gregarious behavior in lobsters, also known for extant lobsters, thus developed earlier in earth's history than previously known. Moreover, this is one of the oldest known examples of decapod crustaceans preserved within cephalopod shells

Comment on the letter of the Society of Vertebrate Paleontology (SVP) dated April 21, 2020 regarding “Fossils from conflict zones and reproducibility of fossil‑based scientific data”: Myanmar amber

Non peer reviewe

Reappraisal of the burrowing lobster <i>Axius </i>(Malacostraca: Decapoda: Axiidea) in the fossil record with notes on palaeobiogeography and description of a new species

The fossil record of the burrowing lobster Axius is reviewed. A diagnosis based on the characters with preservation potential is supplied. Plioaxius lineadactylus Fraaije et al., 2011, from the Pliocene of Belgium and the Netherlands is considered congeneric with the type species of Axius. As a consequence, Plioaxius is considered a junior subjective synonym of Axius. A newly described species, Axius hofstedtae from the late Oligocene of Denmark is considered the oldest unequivocal representative of Axius. Both fossil species, A. hofstedtae n. sp. and A. lineadactylus n. comb., share numerous morphological characters with extant Axius stirhynchus. Scarcity of the Cenozoic Axiidae is ascribed to lack of study of the fossil record of this group rather than to low fossilization potential of its representatives. A preliminary scenario of the migration of Axius based on the scarce fossil record suggests the origin in the Western Tethys and subsequent dispersal westward into the West Atlantic and eastward into the West Pacific

A new species of possible archipolypodan millipede from the Carboniferous of the Netherlands with unusually long tergites

&lt;p&gt;Millipedes have a long evolutionary history, with the oldest presumed fossils of Diplopoda de Blainville &lt;i&gt;in&lt;/i&gt; Gervais, 1844 being from the Silurian and the first definite fossil record originating from Devonian deposits. The phylogeny of Diplopoda is not fully resolved yet, especially not concerning fossil representatives. At&nbsp;the same time, already in the Palaeozoic millipedes showed quite a morphological and presumably also ecological variety. We&nbsp;describe here a new species of a Carboniferous millipede from the Westphalian&nbsp;A of the Netherlands, &lt;i&gt;Lauravolsella willemeni&lt;/i&gt; n.&nbsp;gen.,&nbsp;n.&nbsp;sp., a possible representative of Archipolypoda (†Archipolypoda Scudder, 1882). The species is based on a single specimen, preserved with part and counterpart, which both show a three-dimensional preservation. The specimen has unusually long tergites, in normal life position covering most of the following segment. These long tergites might have been beneficial when performing defensive enrolling. In&nbsp;extant millipedes, enrolling is usually facilitated by softer areas between the sternites, allowing for a certain degree of ventral compression. In&nbsp;the new fossil, the sclerotic sternites occupy the entire length of the ventral side of the segment, not allowing for any type of compression. The new fossil therefore demonstrates another solution for the mechanical challenges during enrolment and increases the morphological diversity of Carboniferous millipedes.&lt;/p&gt

Measurements (in mm) of the three lobster specimens.

<p>Their relative dimensions vary somewhat, possibly related to the compression.</p

Impression of the Posidonia Shale in the quarry in Dotternhausen.

<p>Impression of the Posidonia Shale in the quarry in Dotternhausen.</p

Stratigraphical and biostratigraphical profile of the lower Toarcian Posidonia Shale of Dotternhausen (modified after[34] with permission given by SEPM (Society for Sedimentary Geology)).

<p>The specimen was collected near the Inoceramenbank, at 400 cm depth.</p