| Coryphella trilineata | |
|---|---|
 | |
| Coryphella trilineata nearAvila Beach,California | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Order: | Nudibranchia |
| Suborder: | Cladobranchia |
| Superfamily: | Fionoidea |
| Family: | Coryphellidae |
| Genus: | Coryphella |
| Species: | C. trilineata |
| Binomial name | |
| Coryphella trilineata O'Donoghue, 1921[1] | |
| Synonyms[1] | |
List
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Coryphella trilineata, also called thethree-lined aeolid, is aspecies ofaeolidnudibranch in the familyCoryphellidae.[1] It is considered common inCalifornia,[2] but is also found between southernCanada and northernMexico.[3]
Coryphella trilineata was originally described in 1921 byCharles Henry O'Donoghue from a single specimen captured inNanoose Bay,British Columbia.[4] Though its name is currently the same as its original description, it has also been referred to by several synonyms.[1] To complicate things, several presumed species were later found to be synonymous with this taxon, includingCoryphella piunca in 1961[5] andCoryphella fisheri in 1966.[2]
Coryphella trilineata can reach lengths of between 5–20 mm (0.20–0.79 in),[6] with a maximum length of 35 mm (1.4 in).[7] They possess between 32–34 conicalcerata. All cerata are found behind therhinophores,[4] and may be between 1–2 mm (0.039–0.079 in) in length.[2] The rhinophores do not contract, and have blunt ends. The genital pore is located on the right side of the body, towards the head.[4]
This species is quite similar toCoryphella verrucosa,Coryphella lineata, andPacifia goddardi, but can be distinguished by possessing perfoliate rhinophores, a distinctradula, and 3 lateral stripes.[4][8]
Theradula is yellow in coloration, and possesses between 24–26 rows of teeth, with 3 teeth per row. The centralmedian tooth is U-shaped with a spine in the center. 6 spines surround the median tooth on each side, and are distinctly more robust than those found inCoryphella verrucosa. Thelateral teeth are shaped likeright triangles, with thehypotenuse bearing 1 large spine plus 8–10 smaller spines.[4]
One of the most distinguishing characteristics of this species is its stripes.C. trilineata possesses three white lines on the back and sides. The line down the middle of the back passes between the rhinophores where it splits and continues to the tips of the oral tentacles. The body is white or grey, the cerata are transparent with red interiors, and the rhinophores have yellow tips.[4]
Coryphella trilineata is found in theintertidal zone along theEastern Pacific coast. It can be found as far north asVancouver Island and as far south as theCoronado Islands.[3] Specific occurrences have been reported atDillon Beach, Point Pinos,Monterey Bay,[5] nearWaddell Creek, andPoint Cabrillo.[2] It may live onhydroids,[2][5]eelgrass,[6] ormacroalgae.[2] It may also be found as deep as 27 m (89 ft).[4]
Coryphella trilineata feeds onhydroids, including those in the orderLeptothecata,[9] as well asTubularia spp.,Eudendrium californicum,[7] andEctopleura crocea.[10]
TheamphipodPodocerus cristatus is thought to mimic this species (among others) based on its very similar coloration. It is hypothesized that this is an example ofBatesian mimicry, asC. trilineata is known to possesscnidosacs that discourage predators.[11][12]
Like othernudibranchs,Coryphella trilineata lays eggs in a twisting mass called a ribbon. This species in particular lays white eggs with about 600–700 individual capsules for every 2 mm (0.079 in) of ribbon.[6] Each capsule may contain between 1–2 individual embryos.[10] The ribbon is very thin, and is anchored to asubstrate (such as the blades ofZostera marina).[6]
Once the egg mass is laid, theembryos begin development immediately. Within about 54 hours at 16 °C (61 °F), the embryos will have reached thegastrula stage. Within the next day, they have becometrochophore larvae, complete withcilia andstatocysts. Before they hatch, they will also develop thefoot and shell-secreting glands. Once the shell starts to develop, the embryos will have reached theveliger larval stage, and they will hatch from the egg ribbon.[6]
When the eggs eventually hatch, the resulting larvae have long cilia, which they use to both swim around and capturephytoplankton to eat.[6][10] The coiled larval shell is around 0.1 mm in length, and eyespots are not present.[10]