Coloration and ontogenetic features of fluviatile species of <Emphasis Type="Italic">Rhinogobius</Emphasis> (Gobioidei: Gobiidae) in Amami-oshima Island,Ryukyu Islands,Japan

 The fluviatile Rhinogobius sp. 1 (hereinafter R. sp. 1) (Japanese name kibara-yoshinobori or English name yellow belly medium-egg type) is broadly distributed in the Ryukyu Islands ranging from Amami-oshima Island to Iriomote Island. However, based on the molecular evidence, this species has probably had multiple origins from amphidromous species. We compared the coloration of specimens at Amami-oshima I. with that of the other specimens (islands) in the Ryukyu Is. Amami-oshima I. specimens of R. sp. 1 were different from the specimens of other populations in having five to six cross lines on the caudal fin. We examined the early life history of fluviatile Rhinogobius at Amami-oshima I., based on rearing experiments, and estimated the age of wild specimens by counting otolith increments. Spawned egg capsules of “Rhinogobius sp. 1” at Amami-oshima I. were larger than those of amphidromous species. Their developmental stage in newly hatched larvae was similar to that of Okinawan R. sp. 1 in having a straight notochord; however, it had a flexed notochord earlier than that of Rhinogobius sp. 2 (hereinafter R. sp. 2) (aobara-yoshinobori or blue belly medium-egg type). The ontogenetic trajectory of “Rhinogobius sp. 1” in Amami-oshima I. was similar to Okinawan R. sp. 1 (30 days in larval duration) but different from R. sp. 2 (15 days). In amphidromous relatives of R. sp. 2, developmental timing during larval period was earlier than in the amphidromous relatives of R. sp. 1. It has been suggested that the phenomenon of fluvial landlocking has been accompanied somewhat by egg size increase (on the basis of a few examples). However, the ontogenetic trajectories of fluviatile Rhinogobius species may be a reflection of those of ancestral amphidromous species. Received: March 18, 2002 / Revised: November 7, 2002 / Accepted: December 10, 2002     

The Dictyostelium developmental cDNA project: generation and analysis of expressed sequence tags from the first-finger stage of development.

In an effort to identify and characterize genes expressed during multicellular development ill Dictyostelium, we have undertaken a cDNA sequencing project. Using size-fractionated subsets of cDNA from the first finger stage, two sets of gridded libraries were constructed for cDNA sequencing. One, library S, consisting of 9984 clones, carries relatively short inserts, and the other, library L, which consists of 8448 clones, has longer inserts. We sequenced all the selected clones in library S from their 3'-ends, and this generated 3093 non-redundant, expressed sequence tags (ESTs). Among them, 246 ESTs hit known Dictyostelium genes and 910 showed significant similarity to genes of Dictyostelium and other organisms. For library L, 1132 clones were randomly sequenced and 471 non-redundant ESTs were obtained. In combination, the ESTs from the two libraries represent approximately 40% of genes expressed in late development, assuming that the non-redundant ESTs correspond to independent genes. They will provide a useful resource for investigating the genetic networks that regulate multicellular development of this organism.