Neoglyphea inopinata is a species of glypheoid lobster, a group thought long extinct before Neoglyphea was discovered. It is a lobster-like animal, up to around in length, although without claws. It is only known from 17 specimens, caught at two sites – one at the entrance to Manila Bay in the Philippines, and one in the Timor Sea, north of Australia. Due to the small number of specimens available, little is known about the species, but it appears to live up to five years, with a short larval phase. A second species, previously included in Neoglyphea, is now placed in a separate genus, Laurentaeglyphea.
Taxonomy
Neoglyphea inopinata was named in 1975 by Jacques Forest and Michèle de Saint Laurent of the in Paris. It was based on a single damaged specimen that had been caught by the USFC Albatross in the Philippines in 1908, and deposited in the United States National Museum. De Saint Laurent examined the unidentified specimen while working on Thalassinidea at the Smithsonian Institution. The name Neoglyphea means "new Glyphea", while the specific epithet means "unexpected".
A second extant species of glypheoid was originally placed in the genus Neoglyphea as Neoglyphea neocaledonica, but was later split into a separate genus, Laurentaeglyphea.
Significance
Until the discovery of Neoglyphea, the Glypheoidea was thought to have died out before the end of the Eocene, . They had been thought to be closely related to spiny lobsters and slipper lobsters, with which they formed the group "Palinura". Study of non-fossil specimens made it apparent that the similarities between the two groups resulted from analogy, rather than homology, and that Glypheoidea was closer to lobsters and crayfish. Glypheoidea is occasionally included within the infraorder Astacidea, but molecular analysis using the DNA of Neoglyphea and Laurentaeglyphea suggest that it is better placed as a separate infraorder, Glypheidea.
Distribution
Neoglyphea has been caught in two distantly separated geographical areas. The initial specimens were from a small area at the entrance to Manila Bay at depths of . Three additional specimens have been recovered from a locality in the Timor Sea (near ) at a depth of .
Description
The overall length of the known specimens of Neoglyphea varies from to .
Cephalothorax
The cephalothorax is almost entirely covered by a carapace, only the insertion of the eyestalks protruding slightly beyond it. A deep transverse groove, called the cervical groove, divides the anterior 40% of the carapace from the posterior 60%. At the front, the carapace bears a fairly long rostrum, which is wide at the base, giving it a triangular outline when seen from above. From the side, it is curved in a weak S-shape, bending initially upwards, and then curving slightly forwards again. The cephalothorax becomes slightly wider behind the cervical groove. The carapace, including the rostrum, is covered with forward-pointing teeth (pointed tubercles), including two rows side-by-side along the animal's midline; these rows bridge the cervical groove, but become weaker in the posterior half of the carapace. Beneath the carapace is a branchial chamber, containing 28 pairs of gills.
The underside of the cephalothorax is dominated in the forward part by an unusually long epistome, which is a "most distinctive" feature of Neoglyphea. The epistome is effectively the sternite of the antennal segment, and lies between the base of the antennae and the beginning of the labrum. In Neoglyphea, it is 1.5 times longer than it is wide, and is broadly rectangular in outline. Like the carapace, it is covered in spiny tubercles, although they are smaller and straighter on the epistome. Two rows of larger spines diverge towards the rear of the epistome, leaving an area which is largely devoid of such spines.
Abdomen
The form of the abdomen of Neoglyphea is similar to that of lobsters and other long-bodied decapods. Its first segment is less than half the length of the succeeding 6 segments. The abdomen ends in a telson, which is about 1.5 times as long as the other abdominal segments, flanked by a pair of uropods. The uropods have similarly sized exopods and endopods, fringed with long hairs; the exopod is divided towards the end by a jointed diaeresis.