Revisiting the chondrichthyan egg capsules inventory from the Pennsylvanian (Carboniferous) of Belgium: new data and perspectives.

Records of chondrichthyan egg capsule morphotypes from the paralic deposits of the Belgian Coal Measures Group (Pennsylvanian; Bashkirian-Moscovian; Namurian B-Westphalian B according to the traditional subdivision) are presented and discussed. These include several species of the hybodontiform type Palaeoxyris as well as the putative holocephalian types Vetacapsula and Crookallia. Furthermore, the type specimens of Scapellites cottoni and S. minor, two additional putative and enigmatic egg capsules from the same lithostratigraphic unit, are figured and discussed. Altogether, a highly diverse egg capsule assemblage documented from the Belgian deposits implies the presence of at least eleven different Carboniferous chondrichthyan species using the ancient aquatic environments for spawning and as nurseries. The absence of the xenacanthiform morphotype Fayolia, known from surrounding coeval Coal Measures areas of northern France, the Netherlands, and Germany, is conspicuous. This lack may be a result of collecting bias and does not reflect a real pattern.

The erroneous chondrichthyan egg case assignments from the Devonian: implications for the knowledge on the evolution of the reproductive strategy within chondrichthyans.

Spiraxis interstrialis, and its junior synonym Fayolia mourloni, an uppermost Famennian (Upper Devonian) fossil first described as algae and subsequently interpreted as the oldest known chondrichthyan egg case, is reinvestigated based on the discovery of several additional specimens in Belgian collections. New data, in particular from micro-CT imaging, allow to refute S. interstrialis, and by extension also Spiraxis major (the type species of Spiraxis Newberry, non Adams) and Spiraxis randalli from the Famennian of New York and Pennsylvania, as chondrichthyan egg cases. Alternative interpretations of these enigmatic helicoidal fossils are discussed. The first occurrence of oviparity in the fossil record of chondrichthyans is thus not as old as previously thought and is close to the first occurrence of viviparity in this group, both being recognised now in the Mississippian. The question of which of both conditions is plesiomorphic within chondrichthyans, and more widely within vertebrates, is discussed. Also, the presence of the genus Spiraxis in both the USA (east coast) and Belgium reinforces the strong faunal resemblance already observed in both palaeogeographical areas. It suggests important faunal exchanges between these regions of the Euramerica landmass during the Famennian.

Late Devonian (Frasnian) phyllopod and phyllocarid crustacean shields from Belgium reinterpreted as ammonoid anaptychi.

The taxonomic affinities of fossils from the Frasnian succession of Belgium previously described as phyllopod and phyllocarid crustacean shields are discussed. The rediscovery of the holotype of Ellipsocaris dewalquei, the type species of the genus Ellipsocaris Woodward in Dewalque, 1882, allows to end the discussion on the taxonomic assignation of the genus Ellipsocaris. It is removed from the phyllopod crustaceans as interpreted originally and considered here as an ammonoid anaptychus. Furthermore, it is considered to be a junior synonym of the genus Sidetes Giebel, 1847. Similarly, Van Straelen's (1933) lower to middle Frasnian record Spathiocaris chagrinensis Ruedemann, 1916, is also an ammonoid anaptychus. Although ammonoids can be relatively frequent in some Frasnian horizons of Belgium, anaptychi remain particularly scarce and the attribution to the present material to peculiar ammonoid species is not possible.

Recent thecideide brachiopods from a submarine cave in the Department of Mayotte (France), northern Mozambique Channel.

For the first time large numbers of thecideide brachiopods have been collected from the Mozambique Channel, more particularly from the western part of the Comorian Island of Mayotte (France). The moderately diverse brachiopod fauna is from a submarine cave situated on the second barrier reef encircling this island, with three different genera being found: Thecidellina, Ospreyella and Minutella. The last genus is represented by M. cf. minuta (Cooper, 1981), which was first discovered around Madagascar. Ospreyella is represented by a new species (O. mayottensis sp. nov.) as is Thecidellina, which is represented by T. leipnitzae sp. nov. This species is markedly distinct from T. europa Logan et al., 2015 from Europa Island in the southern Mozambique Channel (1,200 km south of Mayotte), providing an example of allopatric speciation in an isolated cryptic habitat.

Extreme reduction of morphological characters: a type of brachidial development found in several Late Cretaceous and Recent brachiopod species-new relationships between taxa previously listed as incertae sedis.

Size reduction and development of a simplified brachidial structure occurred several times during the long evolution of the Phylum Brachiopoda. Even Recent forms may be micromorphic and paedomorphic with reduced brachidia or none at all. A revision of the Maastrichtian (Late Cretaceous) Terebratella (Morrisia?) suessi Bosquet, 1859 has allowed us to erect a new genus, Jagtithyris gen. nov., because its singular brachidium development does not match any platidiid structure. Such a brachidium has also been observed in another European Late Cretaceous brachiopod, which indicates that this type was not a unique morphological curiosity. This species is the micromorphic Campanian-Maastrichtian Leptothyrellopsis polonicus Bitner Pisera, 1979, which has brachidial structures in common with Jagtithyris suessi comb. nov., although a number of differences have been observed. The genera Leptothyrellopsis and Jagtithyris gen. nov., are included in a new family, Jagtithyrididae fam. nov. During an ongoing revision of extant brachiopod faunas we have been led to recognize a link between this family and representatives of the genus Simplicithyris Zezina, 1976. The taxonomic position of this peculiar group is also discussed.

A reappraisal of the genus Tethyrhynchia Logan, 1994 (Rhynchonellida, Brachiopoda): a conflict between phylogenies obtained from morphological characters and molecular data.

The genus Tethyrhynchia Logan in Logan Zibrowius, 1994 is revised on the basis of different methods of analysis including SEM observations, detailed ontogenetic study of the crural development, transverse serial sections, and shell microstructure. Some morphological characters cited in the original diagnosis are analysed and contested by the ontogenetic results. The type of crura of Tethyrhynchia, often placed in the arcual group, appears to be of the raducal group, instead. Paedomorphosis and heterochronic development offer the possibility of opening a dialogue between morphological and phylogenetic approaches to classification of rhynchonellide brachiopods.

Recent thecideide brachiopods (Thecideida, Thecideoidea) from northern Sulawesi (Indonesia) with discovery of a new Thecidellina species (Thecidellinidae).

The scope of this paper concerns the species diversity of thecideide brachiopods living in the western Pacific equatorial region of Indonesia and the possibilities for circulation and dispersion of thecideide species along the coasts of Sulawesi and the Sea of Bali. The discovery of a new Thecidellina species, Thecidellina mawaliana sp. nov., adds a new genus to the Indonesian fauna. This species has a peculiar biogeography, different from those of Minutella cf. minuta (Cooper, 1981) and Ospreyella mutiara Simon Hoffman, 2013, other thecideides living together with the new species. Unfortunately, attempts to collect molecular sequence information from the specimens failed due to insufficient DNA preservation. Probable speciation mechanisms in this genus are discussed.

Lenticellaria and Hillerella, new kraussinoid genera (Kraussinoidea, Brachiopoda) from Indo-Pacific and Red Sea waters: evolution in the subfamily Megerliinae.

Two new kraussinid brachiopod genera, namely Lenticellaria gen. nov. and Hillerella gen. nov. are described from Pacific waters in the sub-equatorial zone in the Indonesian Archipelago, from Indian Ocean waters in Madagascar and from Red Sea waters in Egypt (Gulf of Aqaba) and Sudan. This fills the equatorial gap in the distribution of the superfamily Kraussinoidea, known from higher latitudes in both hemispheres. The micromorphic new material described is an excellent example of homeomorphy in brachiopods. It also provides new information on the distribution of the genus Megerlia sensu stricto and illustrates subtle variations in the evolutionary process of the reduced brachidium in Kraussinoidea.