Cribrimorph and OtherCauloramphusSpecies (Bryozoa: Cheilostomata) from the Northwestern Pacific

Abstract

We provide original descriptions for nine new species in the cheilostome bryozoan genus Cauloramphus (C. gracilis, C. ordinarius, C. amphidisjunctus, C. cheliferoides, C. oshurkovi, C. infensus, C. parvus, C. peltatus, and C. ascofer) and a redescription of C. disjunctus Canu and Bassler, 1929. We delineate a group of eight species, here termed the 'C. disjunctus clade,' that have the opesial spine joints calcified to a greater or lesser extent in mature zooids; most also have paired, hypertrophied avicularia. This group includes C. amphidisjunctus, C. cheliferoides, C. infensus, C. parvus, C. peltatus, and C. ascofer in the Aleutian Islands, Alaska; C. oshurkovi in the Commander Islands; and C. disjunctus in Japan. High levels of apparent endemism in two unrelated bryozoan genera (Cauloramphus and Monoporella), and geographical population differentiation in C. ascofer indicating ongoing allopatric speciation, suggest high speciation rates for deep benthic bryozoans in the western Aleutians. A phylogenetic hypothesis for the C. disjunctus clade indicates that populations of Cauloramphus dispersed between the Aleutians and Asia on at least three separate occasions, and that the polarity of at least two of these dispersal events was from the Aleutians to Asia.

Integrating fossils and molecules to study cupuladriid evolution in an emerging Isthmus

“…Indeed, the Indonesian Throughflow may be the best analogy we have today for the processes existing for several millions of years prior to the final emergence of the Isthmus of Panama. Recent studies also suggest similar local isolations and subsequent allopatric speciation of other cheilostome bryozoans in the Aluetian straits (Dick 2008;Dick et al 2011).…”

Division of labor and recurrent evolution of polymorphisms in a group of colonial animals

“…Although there was evidence that both the costal shield and ascus evolved independently several times in cheilostomes (Voigt 1991;Gordon 2000), the discovery of the parallel Neogene origin of these structures in closely related species within a single welldefined genus, Cauloramphus, in the large anascan family Calloporidae, forced a reassessment of the significance and pervasiveness of convergence in these structures (Dick et al 2009(Dick et al , 2011. Several Cauloramphus species comprise a transition series, from a stereotypical anascan with an exposed frontal membrane surrounded by jointed opesial spines (Fig.…”

“…a C. ordinariusDick et al, 2011. b C. cheliferoides Dick et al, 2011. c C. peltatus Dick et al, 2011. d C. ascofer Dick et al, 2011 …”

Morphology and palaeobiogeography of Retelepralia, a distinctive cheilostome bryozoan new to the fossil record

“…HincKs (1885) showed that separation of zooids in other cheilostomes is not necessarily a generic character as it occurs in species belonging to several different genera. A good example is seen in the genus Cauloramphus in which tubules are lacking in the majority of species but are present in C. disjunctus canu & BasslEr, 1929and C. amphidisjunctus DicK, Mawatari, sannEr & griscHEnKo, 2011(DicK et al 2011.…”