Fritillaria (tunicate)


Fritillaria is a genus of larvacean tunicates belonging to the family Fritillariidae.

Anatomy and behavior

Fritillaria differs from other larvaceans like the well-studied Oikopleura by having an elongated trunk region, divided into three distinct sections.
Only the anterior section, comprising the mouth, pharynx and cerebral ganglion, is covered in oikoplastic epithelium. It features a dorsal projection of epithelium, comprising many cellulose-secreting oikoplasts.
The middle section, connected to the front by the oesophagus, comprises the gut and anus, and connects to the tail. In the larva, it is covered by the epithelium, before the latter retracts to the anterior lobe and differentiates into oikoplasts.
The posterior section houses the gonads, growing inside an extension of the trunk.
The latter two sections are devoid of epidermis, instead replaced by a thin cuticular layer secreted by the epithelium during the larval stage.

House

Like other larvaceans, Fritillaria secretes a house made of mucopolysaccharides and cellulose, helping catch food particles for filter-feeding. However, Fritillaria's house does not fully cover the animal, instead only expanding on the anterior side. Also, instead of being discarded when clogged like in other larvacean genera, it is here regularly inflated and deflated, helping cleaning off clogged particles.

Distribution

Fritillaria is a widespread genus of larvaceans. Unusually for larvaceans, F. rex has been reported to occur deep into the bathypelagic zone in Monterey Bay.

Species

Fritillaria aberrans Lohmann, 1896Fritillaria abjornseni Lohmann, 1909Fritillaria aequatorialis Lohmann, 1896Fritillaria amphigonadis Hopcroft & Robison, 2005Fritillaria antarctica Lohmann, 1905Fritillaria arafoera Tokioka, 1956Fritillaria borealis Lohmann, 1896Fritillaria charybdae Lohmann, 1926Fritillaria drygalskii Lohmann, 1923Fritillaria fagei Fenaux, 1961Fritillaria formica Fol, 1872Fritillaria fraudax Lohmann, 1896Fritillaria gracilis Lohmann, 1896Fritillaria haplostoma Fol, 1872Fritillaria helenae Bückmann, 1924Fritillaria lucifer Hopcroft & Robison, 2005Fritillaria megachile Fol, 1872Fritillaria messanensis Lohmann in Bückmann, 1924Fritillaria pacifica Tokioka, 1958Fritillaria pellucida Fritillaria polaris Bernstein, 1934Fritillaria ragusina Garić & Batistić, 2010Fritillaria rex Hopcroft & Robison, 2005Fritillaria tenella Lohmann, 1896Fritillaria urticans Fol, 1872Fritillaria venusta Lohmann, 1896