Eucidaris tribuloides

Eucidaris tribuloides, sometimems called the slate pencil urchin, belongs to the order Cidaroida. It is the sister group of the Euechinoida, the order which contains the more common sea urchins of North American shores such as S. purpuratus and L. variegatus.


These two branches of the echinoderm phylogenetic tree diverged about 255 MYA. E. tribuloides is found from North Carolina to Brazil and throughout the Caribbean Basin. Although it ranges down to 800 meters in depth is most commonly found from the surface to 50 m. The slate pencil urchin offers a research model with distinctly different developmental features to the usual models mentioned above. In particular it has a variable number of micromeres and a total lack of early ingressing mesenchyme, a group of cells that secretes the larval skeleton in other species.

Sequence resources for E. tribuloides include a transcriptome assembly and a preliminary genome assembly computed by the Baylor HGSC. The genome assembly contains 637,071 scaffolds labelled as GCA_001188425.1 and described in the Bioproject PRJNA63057. As the genome assembly is preliminary we have not predicted a gene mosdel set from it. The Center for Computational Regulatory Genomics at Caltech created an E. tribloides RNA sequence database from the transcriptome of gastrula stage embryos and combined it with the Roche 454 transcriptome assemblies from Baylor HGSC. The transcriptome sequences from Baylor are available at NCBI under BioPoject 62465.

This portion of the website serves as a user interface for the transcriptome sequence database. It allows users to search the database for genes or contigs of interest and displays the results in terms of purple sea urchin genes and the E. trubuloides contig matches to that gene. The genome assembly and contigs are available as a BLAST database.

Sequence and Scaffold statistics
Assembly Type Number N50(kb)
O.tribuloides v1.0 Scaffolds 637,071 39
O.tribuloides v1.0 Contigs 1,006,568 6