The circulatory system in the blastozooid of the colonial ascidian Botryllus schlosseri (Pallas).
4A): secondgeneration buds (budlets) that are developing from more differentiated buds (first-generation buds), which themselves are attached to adult filter-feeding zooids (blastozooids).
Each blastozooid can propagate both sexually and asexually.
Both processes may also operate in Botryllus schlosseri, where the origin of budding and organogenesis in the new blastozooid derives from a specialized region of the atrial epithelium that appears as a thickened button-like area (Manni et al, 2007; Fig.
Unmanipulated clutches were monitored for fusion or rejection over the oozooid stage (less than 7 days old) and in the week after takeover by the first asexual generation (called a blastozooid
, herein referred to as a zooid) 8-15 days post-settlement.
Reproductive outcomes in these chimeras could be as simple as the direct gametic representation of the diverse blastozooid units in the chimera; or could be as complex as the outcomes of selective resorption or germ cell parasitism that generate skewing from that simple representation (Pancer et al., 1995; Stoner and Weissman, 1996; Stoner et al., 1999; Weissman, 2000).
Until the time of chimeric colony senescence and death, robust blastozooids from all partners appeared to coexist within a single fused colony (Fig.
Remarks: With a barrel form, Thaliacea is characterized by an alternation of asexual (oozooids) and sexual (blastozooids) generations (Esnal, 1996).
NR X NR Juvenile Subphylum Tunicata Class Larvacea Family Fritillaridae NR X NR Fritillaria formica NR X NR Adult Fritillaria haplostoma NR X NR Adult Family Oikopleuridae NR X X Oikropleura longicauda NR X NR Adult Class Thaliacea Family Doliolidae NR X X Doliolum nationalis NR NR NR Ozooids blastozooids TABLE 3 Mean abundance ([+ or -] standard error) ind./[m.sup.3] of new records of zooplankton from Calmita National Park, Limon; from September 2010 to August 2011 Taxa * Set.
Each solitary individual (oozooid) produces, by budding, a stolon which strobilates into chains, between 25 and 75 aggregated individuals (blastozooids), depending on the oozooid size (Heron & Benham, 1985), for Thalia democratica.
After this, several warnings were received during March across the ISCh: March 20 at Maillen Island (600 thousand oozooids and 54 thousand blastozooids per [m.sup.-3]), March 24 at Cholgo Channel and March 29 at Caleta Arena (Fig.
This first generation of blastozooids
produces its own buds, which in turn mature in about a week and subsequently die after giving rise to an additional set of zooids.