| Abstract |
Until recently, the family Glypheidae (Decapoda, Reptantia) was known from fossils only, and consequently presumed extinct for 50 million years. However, in 1975 scientists of the Muséum National d'Histoire Naturelle in Paris recognized a Recent specimen as belonging to this family. The specimen had been collected in the Phillippines in 1908 at approx. 200 m depth, and had remained unidentified in the collections of the Smithsonian Institution, Washington, D.C., since. That same year, the species was described as Neoglyphea inopinata Forest & de Saint Laurent, thus testifying the actual persistence of the group in today's marine fauna. Three expeditions in the same region, in 1976, 1980, and 1985, yielded another 20 specimens, all caught alive. The subsequent study of those specimens would indicate that the phylogenetic position assigned to the glypheids until then had, in fact, been erroneous. The same applied to the other mesozoic families included in the superfamily Glypheoidea. The glypheoids had usually been placed next to the Scyllaridae and Eryonidae in the infraorder Palinura, and been considered probable ancestors of part of the remaining Decapoda Reptantia. However, their similarities would come out to result rather from analogous resemblances than from actual morphological affinities. In fact, after comparison of the principal characters of the three groups, we have been able to confirm that the Glypheoidea did not exhibit any true relationship with the two others. In contrast, they proved to be closer to the Astacidae and could, eventually, be ranked with those in the same infraorder. A number of recent publications, largely by palaeontologists and based in part on cladistic as well as molecular analyses, have lately supported this point of view. They completely reject the inclusion of the glypheoids in the Palinura, corroborate their affinities with the Astacidea, and exclude the possibility that they would represent a primitive group from which other Reptantia could have evolved.
The lineage of the Glypheoidea most probably appeared in the Permian-Triassic, prospered in the Jurassic, and subsequently declined from the Cretaceous to the Eocene. It is apparent that the group has not become extinct during that era, but has silently persisted, without leaving fossil traces, with at least two representatives in today's living world. Indeed, a second species of glypheid has recently been discovered in the southwestern Pacific. Though described under the name Neoglyphea neocaledonica, it shows such differences with N. inopinata that I have established a new genus for this species, Laurentaeglyphea, which is even closer to the glypheids known from the Mesozoic and the Eocene. |
