ANISEED (https://www.aniseed.cnrs.fr) is the main model organism database for the worldwide community of scientists working on tunicates, the vertebrate sister-group. Information provided for each species includes functionally-annotated gene and transcript models with orthology relationships within tunicates, and with echinoderms, cephalochordates and vertebrates. Beyond genes the system describes other genetic elements, including repeated elements and cis-regulatory modules. Gene expression profiles for several thousand genes are formalized in both wild-type and experimentally-manipulated conditions , using formal anatomical ontologies. These data can be explored through three complementary types of browsers, each offering a different viewpoint. A developmental browser summarizes the information in a gene-or territory-centric manner. Advanced genomic browsers integrate the genetic features surrounding genes or gene sets within a species. A Genomicus synteny browser explores the conservation of local gene order across deuteros-tome. This new release covers an extended taxo-nomic range of 14 species, including for the first time a non-ascidian species, the appendicularian Oiko-pleura dioica. Functional annotations, provided for each species, were enhanced through a combination of manual curation of gene models and the development of an improved orthology detection pipeline. Finally , gene expression profiles and anatomical territories can be explored in 4D online through the newly developed Morphonet morphogenetic browser.