Belongs within: Hemichordata. The cephalodiscids Published 25 September 2021 Among the more obscure inhabitants of the world’s oceans are the Cephalodiscidae, a family of small (only a few millimetres in length), largely sessile animals that mostly live in colonies within a shared domicile. Though rarely observed, cephalodiscids have received their fair share of attention due… Continue reading Cephalodiscidae


Belongs within: Reclinata.Contains: Axonophora. In the arms of Pseudisograptus Published 25 April 2021 From the Ordovician to the early Devonian, the graptoloids were a major component of the oceanic fauna. These colonial floaters are among the characteristic fossils of the early Palaeozoic and have received a lot of attention due to their use in biostratigraphy.… Continue reading Bireclinata


Belongs within: Eugraptoloida.Contains: Isograptus, Bireclinata, Tetragraptinae . The Reclinata are a clade of graptoloids defined by Maletz et al. (2009) as the smallest clade including Tetragraptus serra and Exigraptus uniformis. Synapomorphies of the clade include the presence of a rutellum on the ventral side of the sicular aperture, serially homologous ventral projections on the proximal… Continue reading Reclinata


Belongs within: Hemichordata.Contains: Dithecodendridae, Rhabdopleuridae, Wimanicrustidae, Cyclograptidae, Dendroidea. The Graptolithina, graptolites, are a group of colonial organisms known from the Middle Cambrian to the Carboniferous that produced linear, branched or encrusting colonies. Further readings from the rocks Published 6 April 2009 Today, I’m going back to Graptolithina, the graptolites. For those of you who aren’t… Continue reading Graptolithina


Belongs within: Axonophora. The Archiretiolitinae are a group of ‘retiolitid’ graptolites from the Upper Ordovician in which the initial part of the colony remains sclerotised, with the distal arms net-like. <==Lasiograptidae [Archiretiolitinae, Lasiograptinae] |–Hallograptus Lapworth 1876M14 | |–*H. bimucronatus (Nicholson 1869) [=Diplograpsus bimucronatus; incl. Graptolithus whitfieldi]B70 | |–H. inutilis (Hall 1865)R93 | `–H. mucronatusB70 |… Continue reading Lasiograptidae


Belongs within: Dendroidea. Dendrograptus is a long-lived genus of irregularly branching dendroid graptolites that is known from the Middle or Upper Cambrian to the Carboniferous (Bulman 1970). Characters (from Bulman 1970): Generally robust, shrublike in habit, branching irregularly, stipes usually divergent, unconnected, stem well developed, with basal attachment; autothecae denticulate, spined or with apertural processes.… Continue reading Dendrograptus


Belongs within: Bireclinata.Contains: Neograptina, Dicranograptidae, Climacograptidae, Lasiograptidae, Orthograptinae. The Diplograptidae are a group of graptoloids known from the Lower Ordovician to the Lower Silurian. Members of this family have a biserial rhabdosome with a symmetrical proximal end (Fortey & Cooper 1986), with the second theca having a right-handed origin from the first theca. They include… Continue reading Axonophora


Belongs within: Neograptina.Contains: Plectograptinae. Glyptograptus is a genus of graptoloids known from the Lower Ordovician to the Lower Silurian, characterised by the curvature of their thecae (Bulman 1970). Neodiplograptidae [Neodiplograptinae]M14 | i. s.: Korenograptus Melchin et al. 2011M14 | Persculptograptus Koren’ & Rickards 1996M14 | Rickardsograptus Melchin et al. 2011M14 |–Metabolograptus Obut & Sennikov 1985M14… Continue reading Neodiplograptidae


Belongs within: Axonophora. The Dicranograptidae are a group of graptoloids from the Upper Ordovician, characterised by a simple sicula with a dorsal sinus, and partial or complete monoseriality (Fortey & Cooper 1986). The Nemagraptidae are a group of graptoloids known from the Ordovician, with slender stipes that may bear lateral branches (Bulman 1970). <==Dicranograptidae [Dicellograpta,… Continue reading Dicranograptidae


Belongs within: Climacograptidae. Climacograptus is a genus of graptoloids known from the Lower Ordovician to Lower Silurian, with a biserial and nearly circular rhabdosome (Bulman 1970). Characters (from Bulman 1970): Rhabdosome nearly circular in cross section, scalariform views consequently common; thecae strongly geniculate, with deep apertural excavations, supragenicular wall straight, parallel to axis of rhabdosome.… Continue reading Climacograptus