Richard D. Worthington

Floral nectar sugar compositions of some south and Southeast Asian species

Floral nectars of 62 species native to south and southeast Asia were sampled opportunistically, mostly in Malaysia, and analyzed for sugar composition by HPLC. The sugar compositions of these nectars have not been previously reported in the literature. The distribution of the nectars in terms of percentage sucrose tended to be one of two extremes: either high sucrose or low sucrose. Principal pollinators of only a few of these species have been hypothesized in the literature. Most of these had nectar sugar compositions consistent with the principal pollinators posited. A few did not. Sugar compositions of Old World bat-pollinated species were typically found to be much richer in sucrose than those of New World bat flowers and to vary considerably. Possible reasons for these observations are discussed. PLANT SPECIES POLLINATED BY animals have flowers that attract and reward these animals for their visitation. Suites of floral characteristics (e.g., color, size, morphology, and odor) are associated with

Patterns of regional variation in the vertebral column of terrestrial salamanders

Regional variation in the vertebral column of several species of salamanders (families Ambystomatidae, Salamandridae and Plethodontidae) is analyzed. Measurements of three dimensions, centrum length, prezygapophyseal width, and transverse process length, provide the data. Ontogenetic, interspecific, intergeneric and interfamilial patterns of positional variation are diagrammed and discussed. Distinctive patterns of variation characterize the families, genera, and to a lesser extent, the species. The patterns of ambystomatid salamanders are the most generalized, and probably reflect derivation from a primitive ancestral stock. The most specialized conditions occur in the fully terrestrial plethodontids, a group generally considered to be highly derived. Data such as those presented here will aid in the identification of fossils.

Larval Morphology and Ontogeny of the Amby- stomatid Salamander, Rhyacotriton olympicus

Rhyacotriton olympicus is a stream-dwelling ambystoma- tid salamander having a mosaic of primitive (mainly structural) and derived (mainly ecological, developmental and physiological) features. Aspects of the morphology and ontogeny of middle to late larvae are considered. Proportional relationships during ontogeny, and external and microscopic features of the skin of the head and body are recorded. Skulls are well developed at an early age, especially those parts con- cerned with feeding. The last bones to appear are, in order, orbito- sphenoids, prefrontals, lacrimals (from two ossification centers) and septomaxillaries, and formation of lacrimals and septomaxillaries seems to be associated with metamorphosis. Nasal and coronoid bones never form. The anterior part of the otic capsule develops from two centers of ossification. Changes in dentition are marked and involve increases in the numbers of tooth loci on all but the premaxillary bone, during the period of growth studied. The rate of increase is greatest on the dentary. Most larvae lack palatopterygoid teeth, and all lack coronoid teeth; these are derived features in the family. Mineralized gill rakers are few in number. The hyobranchial apparatus is similar to that of other amby- stomatids. The vertebral column develops early, but some caudal verte- brae are added during later stages of larval life. From 42-46 vertebrae comprise the column, usually with 16 trunk and three caudosacral verte- brae. Limbs and girdles are well developed at relatively early ages. Coloration is analyzed, and development of bright yellow ventral pigment in late larval life is documented. The characters of Rhyacotriton are discussed relative to their evolu- tionary significance. The specializations mainly relate to heterochronic modes of evolution, favored by selection pressures associated with life in torrential streams and possibly related to such differential development as the early establishment of feeding and locomotor systems and the retardation of lung development.

FIRST RECORDS OF THE FAIRY SHRIMP STREPTOCEPHALUS MOOREI (BRANCHIOPODA: ANOSTRACA) FROM THE UNITED STATES

Abstract We report the first two records of the fairy shrimp Streptocephalus moorei from the United States, previously known only from its type locality in southeastern Chihuahua, México. An updated morphological diagnosis and habitat data are provided. Streptocephalus moorei, previously considered as a critically endangered species under the IUCN red list criteria, is now assessed as an endangered species on the basis of the following criteria: area of occupancy estimated to be less than 500 km2, known to exist at no more than five locations, and extreme fluctuations in the number of mature individuals. Appropriate measures should be taken to protect this species, such as additional survey efforts and monitoring of extant populations.