"the type specimen of H. longispina is missing from the USNM collections. Moreover, H. longispina has been used indiscriminately for a variety of only distantly related Hantkenina morphotypes with ‘long’ tubulospines. Although the name H. longispina cannot be rejected on the grounds that it is an inappropriate name (ICZN, 1999, Art. 23.3.7), in an attempt to avoid further taxonomic confusion, and because the type specimen of H. longispina is lost, we propose that the name H. longispina be suppressed and H. liebusi adopted as the valid name for these middle Eocene morphotypes."
Coxall, H. K.; Pearson, P. N. (2006). Taxonomy, biostratigraphy, and phylogeny of the Hantkeninidae (Clavigerinella, Hantkenina and Cribrohantkenina. In: Pearson, P.N. et al. (Editors), Atlas of Eocene Planktonic Foraminifera, Cushman Foundation Special Publication 41. Allen Press, Lawrence, Kansas,. 213-256.