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Millipedes have a long evolutionary history, with the oldest presumed fossils of Diplopoda de Blainville in 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 the same time, already in the Palaeozoic millipedes showed quite a morphological and presumably also ecological variety. We describe here a new species of a Carboniferous millipede from the Westphalian A of the Netherlands, Lauravolsella willemeni n. gen., n. 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 extant millipedes, enrolling is usually facilitated by softer areas between the sternites, allowing for a certain degree of ventral compression. In 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. [ABSTRACT FROM AUTHOR]

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.

For the first time, a paguroid shield is recorded from upper Miocene reefal strata (Koronia Member, Pakhna Formation) that crop out along the northern margin of the Troodos Massif, north of the village of Mitsero, Cyprus. Described here as Paguristes joecollinsi sp. nov., it constitutes the first paguroid shield known from Miocene deposits. The paucity of Cenozoic paguroid shields can probably be linked to a collecting bias in view of their relatively small size; in addition, suitable gastropod shells and internal moulds of such should be screened for ‘hidden’ hermit crabs. [ABSTRACT FROM AUTHOR]

During recent decades, decapod crustacean faunas from middle Danian (lower Paleocene) strata at Faxe (Sjælland, Denmark) have been studied in detail. However, paguroid anomurans have not yet been described formally. Two new species of hermit crab have lately been recognised in the collections of the Geomuseum Faxe. Percentages of total paguroid assemblages and feeding behaviour derived from the morphology of its chelae indicate that one of these, Dardanus faxensis sp. nov., as a generalist, was better adapted to inhabit the deep-water reefal environment of the Faxe carbonates than the more specialised, suspension-feeding Paguristes frigoscopulus sp. nov. [ABSTRACT FROM AUTHOR]

Subsequent to a preliminary report on a handful of paguroid remains from the Tithonian (uppermost Jurassic) to lower Berriasian (Lower Cretaceous) Štramberk Limestone in Moravia (eastern Czech Republic), published in 2013, several field campaigns were organised by our research team during the summers of 2012-2015 and 2018. These resulted in the recovery of additional paguroid shields (or, anterior carapaces) that form the basis of the present study. The currently available material documents a diverse paguroid fauna. In fact, it ranks amongst the most diverse fossil paguroid assemblages known, following faunas from the upper Kimmeridgian of Nusplingen (southern Germany) and the Tithonian of Ernstbrunn (northeast Austria). New representatives of five families and five genera are described, named and illustrated, as follows: Annuntidiogenes sagittula sp. nov. (Diogenidae), Protopagurus cerebellum sp. nov. and Protopagurus duopupae sp. nov. (Paguridae), Mesoparapylocheles janetjacksonae sp. nov. (Parapylochelidae), Masticacheles septemgradu sp. nov. (Pilgrimchelidae) and Ammopylocheles romankijoki sp. nov. (Pylochelidae). [ABSTRACT FROM AUTHOR]

Background. The rich fossil record of rorqual and humpback whales (Cetacea, Mysticeti, Balaenopteridae) is mainly characterized by monotypic genera since genera including more than one species are extremely rare. The discovery of new species belonging to known genera would be of great importance in order to better understand ancestor-descendant relationships and paleobiogeographic patterns in this diverse group. Recent discoveries in the southern North Sea Basin yielded a number of reasonably well preserved fossil balaenopterids from the Late Miocene; this sample includes a balaenopterid skull from Liessel, The Netherlands, which shares key characters with Archaebalaenoptera castriarquati from the Pliocene of Mediterranean. This skull is permanently held by Oertijdmuseum, Boxtel, The Netherlands, with the number MAB002286 and is investigated here. Methods. A detailed comparative anatomical analysis of the skull MAB002286 is performed in order to understand its relationships. The age of the skull is determined by dinocyst analysis of the associated sediment. A paleobiogeographic analysis is performed to understand paleobiogeographic patterns within the balaenopterid clade the new skull belongs to. Results. Our work resulted in the description of Archaebalaenoptera liesselensis new species. The geological age of the holotype skull is between 8.1 and 7.5 Ma. The phylogenetic relationships of this species reveals that it is monophyletic with Archaebalaenoptera castriarquati from the Italian Pliocene. Moreover, in combination with a more basal species of Archaebalaenoptera from the late Miocene of Peru, our paleobiogeographic analysis suggests that the North Atlantic ocean played a major role as a center of origin of a number of balaenopterid clades including Protororqualus, Archaebalaenoptera and more advanced balaenopterid taxa. From a North Atlantic center of origin, two dispersal events are inferred that led to the origins of Archaebalaenoptera species in the South Pacific and Mediterranean. The distribution of Archaebalaenoptera was antitropical in the late Miocene. The role played by the Mediterranean salinity crisis is also investigated and discussed. [ABSTRACT FROM AUTHOR]

During fieldwork in the early 1990s at the then still active quarry near Nasiłów, on the left bank of the River Vistula (Wisła), accompanied by Professor Andrzej Radwański, some lobster remains were collected. A fragmentary anterior portion of a decapod crustacean carapace, recovered from a level about 2 m below the Cretaceous-Paleogene (K/Pg) boundary, in a siliceous chalk unit locally referred to as 'opoka', constitutes the oldest record of the thaumastocheliform genus Dinochelus Ahyong, Chan and Bouchet, 2010, D. radwanskii sp. nov. The other, more complete, individual is from c. 3 m above the K/Pg boundary, coming from marly gaizes or 'siwak',this is ascribed to a new species of Hoploparia M'Coy, 1849, H. nasilowensis sp. nov., the first to be recorded from Danian (lower Paleocene) strata. Although both 'opoka' and 'siwak' facies in the Nasiłów area are very rich in diverse biota, including some brachyurans, no macruran remains had so far been recorded from the region. [ABSTRACT FROM AUTHOR]

A paguroid, Lessinipagurus vasjamikuzi sp. nov., is described from Eocene (upper Bartonian-lower Priabonian) of Istria, on the basis of a single right chela from Gračišće near Pazin, western Croatia. The specimen originates from beds of olistostrome breccias that formed in a bathyal setting. In addition, a new genus, Prexylopagurus, accommodated in the new family Xylopaguridae, is erected; based on a distinctive set of characters of the dorsal carapace, chelae, and operculate tergite of sixth abdominal somite. The phylogenetic relationships of the new family Xylopaguridae are discussed; it appears to have originated in the Tethyan Realm, possibly as early as the Jurassic, and displays a Tethyan distribution during the Cenozoic. Three extant species are transferred to the new genus, resulting in three new combinations: Prexylopagurus anthonii, P. philippinensis, and P. caledonicus. The palaeoecology and palaeobiogeography of the newly erected taxa are discussed. The bloom of diversity of Lessinipagurus during the late Eocene parallels the evolution and subsequent ecological expansion of grasses, especially of reed and bamboo, thus constituting a rare example of coevolution between land plants and marine organisms. The holotype of Lessinipagurus vasjamikuzi sp. nov. shows remains of an interesting syn-vivo balanomorph association; this is the earliest record of such barnacles on a decapod crustacean in the fossil record, and the sole record from an anomuran to date. [ABSTRACT FROM AUTHOR]

Extinct anomurans are known mostly by their carapaces. Regions in the fossil carapace are well delimited by grooves and, by comparison with extant hermit crabs, they can be referred to the underlying internal organs. In this paper we examine the allometric effects in ontogeny of two Jurassic hermit crabs of an extinct genusGastrodorus:G. neuhausensisvon Meyer, 1864 andG. bzowiensissp. nov. described herein. Both species occur in Oxfordian and Kimmeridgian strata in southern Poland, but the former species only in southern Germany. Samples of carapaces of both species consisted of carapaces of a wide size range, illustrative of the various ontogenetic stages. A reduced major axis was applied for assessment of allometry. The most pronounced positive allometric effect in both species concerned the posteriormost region of the cephalothoracic shield, which became disproportionally more elongated than the overall carapace length (positive allometry) as overall size increased. Statistically significant differences between the two species concern the cardiac region, which gained in length with size inG. neuhausensis(positive allometry) and became proportionally narrower in the new species (negative allometry). Thus it may be assumed that overall growth rate of the heart region was less in the latter species. Additionally, new terminology of carapace regions previously introduced to pagurids and based on morphology of recent representatives is applied to the gastrodorids. http://zoobank.org/urn:lsid:zoobank.org:pub:E64D2515-BD0D-4A78-83A7-D35C5F9FA3E5 [ABSTRACT FROM AUTHOR]

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 entirely. [ABSTRACT FROM AUTHOR]

On the basis of carapaces, three new genera and species of symmetrical paguroid anomurans are described. Diogenicheles theodorae, Masticacheles longirostris,a n d Pilgrimcheles karolinae constitute the oldest known members of the family Parapylochelidae. As noted previously, assemblages fromsponge-reefal strata of Oxfordian (Late Jurassic) age in the southern Polish Uplands document an important radiation event amongst paguroids. Compared to the present day, the Parapylochelidae were more diverse during the mid-Mesozoic; they appear to have withdrawn from shallow, reefal waters to deep-water settings from the Late Jurassic onwards. Paguroid faunas from the Oxfordian of Europe already are highly diverse, both morphologically and phylogenetically, and comprise early members of the families Diogenidae, Pylochelidae, and Parapylochelidae. This suggests that the evolutionary history of paguroids started much earlier (i.e., in pre-Jurassic times) than previously assumed. New terms for several typical paguroid carapace regions are introduced and on the basis of carapace morphology and ecological shifts hypotheses on the early speciation of hermit crabs are put forward. [ABSTRACT FROM AUTHOR]

Parasites are common in modern ecosystems and are also known from the fossil record. One of the best preserved and easily recognisable examples of parasitism in the fossil record concerns isopod-induced swellings in the branchial chamber of marine decapod crustaceans. However, very limited quantitative data on the variability of infestation percentages at the species, genus, and family levels are available. Here we provide this type of data for a mid-Cretaceous (upper Lower Cretaceous, upper Albian) reef setting at Koskobilo, northern Spain, on the basis of 874 specimens of anomurans and brachyurans. Thirty-seven specimens (4.2%), arranged in ten species, are infested. Anomurans are more heavily infested than brachyurans, variability can be high within genera, and a relationship may exist between the number of specimens and infestation percentage per taxon, possibly suggesting host-specificity. We have also investigated quantitative patterns of infestation through geological time based on 88 infested species (25 anomurans, 55 brachyurans, seven lobsters, and one shrimp), to show that the highest number of infested species can be found in the Late Jurassic, also when corrected for the unequal duration of epochs. The same Late Jurassic peak is observed for the percentage of infested decapod species per epoch. This acme is caused entirely by infested anomurans and brachyurans. Biases (taphonomic and otherwise) and causes of variability with regard to the Koskobilo assemblage and infestation patterns through time are discussed. Finally, a new ichnogenus and -species, Kanthyloma crusta, are erected to accommodate such swellings or embedment structures (bioclaustrations). [ABSTRACT FROM AUTHOR]

A new species of diogenid paguroid, Eopaguropsis nidiaquilae, the earliest known member of the family to date, is recorded from sponge-reefal strata of Oxfordian (Late Jurassic) age in the southern Polish Uplands. Morphological features of the carapace suggest that the family Diogenidae diverged from other paguroid lineages such as the Pylochelidae and Parapaguridae, long before the Oxfordian Stage (161.2-155.7 Ma). The typically deep, V-shaped cervical groove of diogenids most likely was the product of fusion of the branchiocardiac and cervical grooves of their predecessors. [ABSTRACT FROM AUTHOR]

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 longterm 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. [ABSTRACT FROM AUTHOR]

All known etyid crabs (Crustacea, Decapoda) from the upper Albian - lower Cenomanian Aldoirar coralgal-dominated patch reef (Albeniz Unit, Eguino Formation), as exposed at the disused Koskobilo quarry in Navarra, northern Spain, are described, discussed and illustrated. A new species, Xanthosia koskobiloensis, the first member of the genus on record from southern Europe, is erected, and a variety that appears closely related to this, Xanthosia cf. X. koskobiloensis, is recognised. This new taxon could be a forerunner of the early Palaeocene (Danian) Xanthosia gracilis from Fakse (Sjælland, eastern Denmark), with which it shares a morphologically closely similar carapace. On the basis of a revised overview here of all species assigned to it, the genus Xanthosia may have evolved in an environment dominated by deposition of siliciclastics, rather than chalks. In addition , Etyxanthosia fossa has been collected at Koskobilo, and as the distribution of all known specimens demonstrates, E. fossa inhabited various environments. Another new species, Caloxanthus paraornatus, is closely similar as well to a species from Fakse, Caloxanthus ornatus, and constitutes the first record of the genus for southern Europe. [ABSTRACT FROM AUTHOR]

Recent fieldwork (June 2008) in the reefal limestones near Alsasua, Navarra (northern Spain) has resulted in the discovery of a new species of diogenid hermit crab, Annuntidiogenes worfi sp. nov., which appears closely related to the type species of the genus, A. ruizdegaonai Fraaije et al., 2008, from Monte Orobe and also of mid-Cretaceous (Albian-Cenomanian) age. The new specimen represents only the third paguroid carapace of Cretaceous age to be described and formally named. [ABSTRACT FROM AUTHOR]

Two new species of hermit crab are recorded from the upper Miocene (Tortonian) St. Marys Formation of Maryland, named Pagurus hazenorum n. sp. and Paguristes timoni n. sp. and assigned to the families Paguridae Latreille, 1802, and Annuntidiogenidae Fraaije, 2014, respectively. Both new species are morphologically close to present-day congeners, but can be differentiated on details of ornament (tubercles, granules and teeth).

A new diogenid paguroid, Paguristes liwinskii sp. nov., is described from upper Albian phosphorite-bearing deposits near Annopol, along the east bank of the River Vistula (Wisła), east-central Poland. This new species constitutes an additional example of Early-Mid-Cretaceous macrofaunal shift, from marine reefal limestone to siliciclastic facies, triggered by the worldwide radiation of planktonic organisms. The species described here is the earliest known member of the genus Paguristes, previously recorded from the upper Santonian/lower Campanian to the Recent.

Two new brachyurans assignable to the family Retroplumidae Gill, 1894, Serrablopluma diminuta n. gen., n. sp., and Gaudipluma bacamortensis n. gen., n. sp., from the Eocene of northern Spain (Huesca, Aragón), substantially enlarge our current knowledge of the morphological diversity of the family. The material, with well-preserved ventral surfaces, permits the erection of two new genera that can be referred to the family with confidence on the basis of the general carapace shape, narrow front, a reduced last pair of pereiopods and characteristic thoracic sternum (broad, trapezoidal sternites 3, 4, subrectangular sternites 5-7, sternite 8 conspicuously reduced and inclined). Serrablopluma diminuta n. gen., n. sp. co-occurs with two other retroplumids in the most diverse fossil assemblage of that family known to date.