Nyctitheriids are primitive insectivores that were relatively abundant and diverse in North America and Europe during the middle Paleocene through to the middle Oligocene. The nyctitheriids from Asia are poorly known and show several distinctive characters. Here we describe the late Paleocene Asionyctia guoi gen. et sp. nov., the first fairly well known Asian nyctitheriid, from the Subeng locality near the city of Erlianhot (Erenhot) in Inner Mongolia, China. Among its most conspicuous features are the paraconid positioned high on p4, the rather primitive morphology and size of p3, the premolariform P4/p4 and the transverse upper molars with a small, straight postcingulum. Except for the paraconid positioned high on p4, these combined features are also present in other Asian nyctitheriids, but absent in North American or European forms. We performed a cladistic analysis, based on a set of 20 dental characters, to solve higher-level phylogenetic relations within Nyctitheriidae. The strict consensus tree groups all Asian forms in a single clade, for which we propose the rank of a subfamily and the name Asionyctiinae subfam. nov. Within Nyctitheriidae, a semimolariform P4/p4, as in Leptacodon tener, is considered primitive, and we consider the morphologically simplified P4/p4 of Asionyctiinae derived within Nyctitheriidae. Asionyctiinae can be derived from an American, primitive Leptacodon-like ancestor migrating into Asia, with the reduction of P4/p4 occurring on the Asian continent. Considering the derived morphology and the relatively high diversity of Asionyctiinae during the Asian late Paleocene, and the inferred conservative nature of the family Nyctitheriidae, we suggest an early Tiffanian time for the migration of nyctitheriids into Asia.
Located in
Library
/
RBINS Staff Publications
/
Pending Duplicate Bibliography Entries
We report on a survey of rotifers from 30 habitats in Kalasin Province, Northeast Thailand, collected during Dec. 2001. One hundred and fifty species were identified. One of them, Lecane lungae sp. nov. is new to science, and two, L. opias (Harring and Myers), and L. stichoclysta Segers are new to the Oriental region and Thailand; the record of L. stichoclysta is the second record ever of the species after its description from Nigeria (Africa). In addition, we illustrate a remarkable morphological variant of Keratella cochlearis. These records, together with the new occurrences of other endemic rotifer species illustrate the remarkable diversity of the Thai rotifer fauna, and add to our knowledge of rotifer chorology.
Located in
Library
/
RBINS Staff Publications
/
Pending Duplicate Bibliography Entries
On occasion of the discovery of a new species of a marine epizoic rotifer of the enigmatic Seisonidae, from Gazi Bay in Kenya, we reassessed the classification of the group. The taxon was until now known to contain only 2 species, viz. Seison nebaliae and S. annulatus, both of which live attached to Crustacea of the genus Nebalia. The new species, Seison africanus sp. nov., was diagnosed by its species-specific trophi morphology and relatively small size. A comparison with the 2 other known seisonid species reveals a sister group relationship between S. africanus sp. nov. and S. nebaliae, based on similarities in trophi structure and, accordingly, an assumed feeding mode and relationship with their hosts. The fundamental differences between these 2 commensal sister taxa and the ectoparasitic S. annulatus prompted a reevaluation of the generic classification of these animals. Accordingly, we propose to reestablish the genus Paraseison Plate, 1887 in order to accommodate P. annulatus (Claus, 1876) (comb. nov.).
Located in
Library
/
RBINS Staff Publications
/
Pending Duplicate Bibliography Entries
