Establishment of Alloptilella splendida gen.et sp.nov.and resurrection of Scytalium veneris(Thomson & Henderson,1906),two sea pens(Cnidaria:Pennatulacea) from seamounts in the tropical Western Pacific

Sea pens are a highly specialized and morphologically distinct group of octocorallians,but many taxa were poorly described and their phylogenetic relationships are still poorly known.We describe two species of sea pens collected from the tropical Western Pacific:Alloptilella splendida gen.et sp.nov.and Scytalium veneris(Thomson Henderson,1906).Alloptilella splendida gen.et sp.nov.accords with the definition of the recently resurrected genus Ptilella Gray,1870 in most characters,but differs from the latter in the arrangement of autozooids and the location of mesozooids.The new species mostly resembles Pennatula naresi K(o|")lliker(1880),but differs by the location of me sozooids and the reddish color of sclerite s surrounding siphonozooids.The generic separation is also well supported by their genetic distances and the molecular phylogenetic trees constructed by the concatenated mtMutS-COI-28 S,where Alloptilella clustered with Scytalium Herklots,1858 and formed a clade with the cluster of Ptilella and Distichoptilum.Scytalium veneris,usually considered as a junior synonym of Scytalium sarsii Herklots,1858,is resurrected by recognizing their distinctive differences.This is the first record of Scytalium veneris outside its type locality,and the phylogenetic analysis indicates that Scytalium is a monophyletic group.Both the families Pennatulidae and Virgulariidae are polyphyletic,and more morphological and molecular data are needed to clarify the phylogenetic positions of pennatulacean families and genera.