Molecular and morphological taxonomy and biogeography of living Cribroelphidiidae, Elphidiellidae, Elphidiidae, Haynesinidae and related taxa (Foraminifera, Rotalioidea)

In this global review we recognise, describe and figure 205 morphospecies of living elphidiids (Cribroelphidiidae, Elphidiellidae, Elphidiidae, Haynesinidae) from around the world and summarise their biogeography. Fifty-eight phylospecies (S1–58) are recognised by DNA sequencing grouping in eight clades and almost all are shown to be morphologically distinguishable. A further 148 morphospecies, that have not yet been sequenced, have sufficiently distinct morphology to be recognised and we hypothesise there could be at least another 100 rather cryptic and less common species that we have not been able to distinguish confidently to include in this review. We recognise the following families and genera: Family Cribroelphidiidae (clade F), containing the genera Cribroelphidium and Protelphidium; Family Elphidiellidae containing the genera Cryptoelphidiella (clades D and E), Elphidiella (clade B), Emayerella (replacement name for Mayerella junior homonym), and Rectoelphidiella; Family Elphidiidae s.l. (clades A, B, H and I), containing the genera Australononion (n. gen.) (clade I), Elphidium (clades A and H), Epistomaroides, Hispidoelphidium (n. gen.), Millettoelphidium (n. gen.) (clade H), Stomoloculina, and Toddinella (clade B); Family Haynesinidae (clade C), containing genera Aubignyna and Haynesina; Family Notorotaliidae, which molecular analyses confirm branches among these “elphidiids” has been reviewed previously and contains genera Buccella, Cristatavultus, Notorotalia, Parrellina and Porosorotalia. The families Elphidiidae and Elphidiellidae are based on morphological characters, as molecular analysis shows them to be polyphyletic but for the moment a clear morphological distinction is not possible for the obtained molecular clades. Seven molecular species and 34 morphospecies are described and named as new: Cribroelphidium calvomarcileseae, C. inflatogunteri, C. knudsenae (S3), C. revetsi (S41), Cryptoelphidiella daisyana, C. schweizerae, Elphidium altenbachi (S49), E. apthorpae, E. canni, E. davidhaigi, E. fajemilai, E. feylinghansseni, E. gischleri, E. goldsteinae, E. hanseni, E. hollisi, “E.” hulmei (S39, S57), E. kawagatai (S33), E. korsuni, E. larsi, E. lobulatum, E. lunatum, E. mouangaae, E. pereirai, E. pilleti (S18), E. poagi, E. sabaaae, E. scottorum, E. thisseni, E. yankoae, Epistomaroides fordererae, Haynesina lecozei, Millettoelphidium culveri (S51), M. yassinii, Protelphidium hottingeri, Toddinella akandaensis, T. crundwelli, T. darlingae, T. grenfelli, T. lutzei, and T. spezzaferriae. Two genotypes of “Elphidium” hulmei are genetically distinct but morphologically cryptic and unable to be separated using morphology. A further 16 unnamed morphospecies are described but not formally named because of insufficient material to do so. A neotype is proposed for Epistomaroides punctulatus (d’Orbigny) and a lectotype for Elphidium owenianum (d’Orbigny). Elphidiids live in mostly shallow seas (hyposaline to hypersaline) and occur throughout the world except for around the coast of the bulk of Antarctica. No species is cosmopolitan but a few (e.g., Australononion simplex, Cribroelphidium clavatum, C. decipiens, C. gunteri, C. knudsenae, C. lidoense, Elphidium advena, E. alvarezianum, E. articulatum, E. fax, “E.” formosum, E. gerthi, E. hanseni, E. jenseni, E. longipontis, Haynesina germanica, Hispidoelphidium hispidulum, Preotelphidium schmitti and Toddinella incerta) are widespread in two or more ocean regions, whereas the majority are endemic to smaller areas. Twenty biogeographic “provinces” are recognised by cluster analysis of presence/absence records with the highest diversities in the northwest Pacific and tropical East Indies-North Australia provinces with 74 and 49 species each. At the highest level of clustering their world biogeography can be divided into three large regions – Arctic and Atlantic; Indian and Pacific; and Southern Ocean. Levels of endemism in our “provinces” range between 0 (five provinces) and 33% (Southern Ocean). This review identifies at least 33 non-indigenous species (2 genotypes, 31 morphospecies) presumably introduced by accidental anthropogenic transfer in the last several centuries, probably in ship’s ballast, across large oceanic barriers to establish disjunct distribution patterns.