Juliidae
From Wikipedia, the free encyclopedia
| Juliidae Fossil range: Eocene–recentPaleocene(?) - Eocene to recent | |
|---|---|
| Drawing of the shell (the exterior of the right valve) of Julia borbonica. | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): | clade Heterobranchia Informal group Opisthobranchia |
| Superfamily: | Oxynooidea |
| Family: | Juliidae E. A. Smith, 1885[1] |
| Genera | |
See text. | |
Juliidae, common name the bivalved gastropods, is a family of minute sea snails, marine gastropod mollusks or micromollusks in the superfamily Oxynooidea, an opisthobranch group.
This family of snails is extremely unusual in that their shells consist of two separate hinged pieces or valves, which are joined by a ligament, and which look nothing like a normal snail shell, but instead look almost exactly like the two hinged valves of a clam, a bivalve mollusk, a very different class of animals.
In the past the Juliidae were known only from fossil shells, and not surprisingly these fossils were therefore interpreted as being the shells of bivalves. Julia, which is the type genus of the family, was named in 1862 by Augustus Addison Gould, who described it as a bivalve genus. Julliidae are known from the Eocene period to the Recent, but they probably first appeared during the Paleocene.[2]
Contents |
Taxonomy as "bivalves"
These bivalved gastropods were for a long time only known from fossils and dead material. Because of this, they had been described as being somewhat atypical bivalves. In the late 19th century they were classified among the bivalves, within the family Mytilidae, the true mussels.[3]
The similarity of the shells of Juliidae to those of bivalves does not mean that these snails are closely related to bivalves; this is an example of convergent evolution.
Discovery of live animals
Up until the mid 20th century, these creatures were still considered to be bivalves. Then finally in 1959, living individuals of one species were collected on the green alga, Caulerpa, in Japan. It was immediately clearly visible that these animals are in fact unusual gastropods with a two-part shell. The first discovered live species of bivalved gastropod was Tamanovalva limax, described by Kawaguti & Baba (1959)[4].
Once the habitat, appearance, and life habits of these very small and inconspicuous animals were understood, in subsequent years researchers were able to find a number of other species and other genera in different parts of the world, also living on various species of Caulerpa.
2005 taxonomy
This family is within the clade Sacoglossa (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005).
The family Juliidae consists of the following subfamilies (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005):
- subfamily Juliinae E. A. Smith, 1885 - synonym: Prasinidae Stoliczka, 1871
- subfamily Bertheliniinae Keen & A. G. Smith, 1961[5] - synonym: Tamanovalvidae Kawaguti & Baba, 1959
- † (fossil) subfamily Gougerotiinae Le Renard, 1980[6]
Description
As Tryon (1884)[3] wrote in his description of the genus Julia: the shell is oblong, thick, and cordiform. The valves are closed, the margins entire and the valves are inequilateral. The lunule is deep circular, projecting into the interior of the right valve, the left valve is in the same place furnished with dentiform tubercles. The hinge line is simple and arched. The ligament is external and narrow. There are two muscle scars which are unequal and subcentral.
These animals have two valves, and the soft parts can be completely withdrawn inside the shell.[7] The two valves are usually thin and translucent.
In the genus Tamanovalva there is a protoconch on the apex of the left valve. This is clearly visible in the left valve of Tamanovalva babai.[8]
The body of the live animals is in most cases green (as it is in many sacoglossans), and in many species the individual appears green in totality. This, combined with the very small overall size, makes the animal hard to see on the green algae on which it lives. This ability serves as crypsis, especially as cryptic coloration (camouflage). In two species [1] and [2] the camouflage is even more complete: the mantle of the animal is patterned in a way that very closely resembles the structure of the alga on which it lives.
The empty valves of the shells of these animals are in some cases green, in other cases brownish-green or yellow, and in yet others, colorless. The species Julia zebra has shells that are finely striped with brown and blotched with white. [3]
Distribution
Species in this family occur in all tropical zone seas and all temperate zone seas.[7]
Life cycle
After hatching out from eggs, the juvenile snails immediately take their place on algae (the larval phase of veliger is extremely short).[9]
Feeding habits
Juliidae feed on green algae[7] of the genus Caulerpa. Some species of Juliidae feed only on one species of Caulerpa, others in the family feed on more than one species of this green alga.
Genera
Based on classification by Jensen (1996)[10], there are three recent genera in the family Juliidae[11]:
- Julia Gould, 1862
- Berthelinia Crosse, 1875
- Tamanovalva Kawaguti & Baba, 1959
The type genus is Julia Gould, 1862.
Subfamilies, genera and species in the family Juliidae include[2]:
Juliinae
- (recent) Julia Gould, 1862 - synonym: Prasina Deshayes, 1863
- (recent) Julia borbonica
- (recent) Julia exquisita (Gould, 1862)[12] - this species was mentioned in report by the Challenger expedition[13][14]
- (recent) Julia japonica Kuroda & Habe, 1951[15][14]
- (recent) Julia mishimaensis Kawaguti & Yamasu, 1982[14]
- Julia thecaphora Carpenter, 1857 - a probable[16] synonym is (recent) Julia zebra Kawaguti, 1981[17]
- (fossil) Candinia Le Renard J., Sabelli B. & Taviani M. 1996[2]
- (fossil) Candinia pliocaenica Le Renard J., Sabelli B. & Taviani M. 1996[2] - from lower Pliocene near Siena in Italy.
- (fossil) Candinia krachi (Baluk & Jakubowski, 1968) - synonym: Berthelinia krachi Baluk & Jakubowski, 1968
Bertheliniinae
- (recent) Berthelinia Crosse, 1875 - type genus of the subfamily Bertheliniinae
- Anomalomya Cossmann, 1887
- Namnetia Cossmann, 1906
- Squamulinia Le Renard, 1989
- (recent) Tamanovalva Kawaguti & Baba, 1959
Gougerotiinae
- (fossil) Gougerotia Le Renard, 1980 - type genus of the subfamily Gougerotiinae
- (fossil) Gougerotia orthodonta Le Renard, 1980
? subfamily (unknown to wikipedians)
- (recent) Edenttellina
- (fossil) Hemiplicatula Deshayes, 1861
- ?Saintia de Raincourt, 1877
- (recent) Midorigai
- (recent) Midorigai australis Burn, 1960[24]
See also
References
This article incorporates public domain text from reference [3].
- ^ Smith E. A. (1885). "Report on the scientific results of the voyage of H. M. S. Challenger". Zoology 13(1): 269.
- ^ a b c d Jacques Le Renard, Bruno Sabelli & Marco Taviani. 1996. On Candinia (Sacoglossa: Juliidae), a New Fossil Genus of Bivalved Gastropods. Journal of Paleontology, Vol. 70, No. 2 (Mar., 1996), pp. 230-235.
- ^ a b c George Washington Tryon, Jr. 1884. Structural and systematic conchology: an introduction to the study of the Mollusca. Volume III. Philadelphia, published by the author, page 267.
- ^ a b Kawaguti S. & Baba K. (1959). "A preliminary note on a two-valved sacoglossan gastropod, Tamanovalva limax, n. gen., n. sp., from Tamano, Japan". Biological Journal Okayama University 5(3-4): 177-184.
- ^ Keen & Smith A. G. 1961. Proceedings of the California Academy of Sciences, ser. 4, 30(2):50.
- ^ Jacques Le Renard. 1980. Bulletin d'Information des Géologues du Bassin de Paris, 17(2): 23.
- ^ a b c (Czech) Rykel H. de Bruyne. 2004. Encyklopedie ulit a lastur. Rebo Productions, 336 pp., ISBN 80-7234-288-6, page 223.
- ^ a b Rudman W. B. 2001 (October 16). Tamanovalva babai Burn, 1965. Sea Slug Forum. Australian Museum, Sydney, accessed 10 May 2009.
- ^ a b Rudman W. B. 2003 (October 4). Berthelinia caribbea Edmunds, 1963. Sea Slug Forum. Australian Museum, Sydney, accessed 10 May 2009.
- ^ Jensen K. R. (1996). "Phylogenetic systematics and classification of the Sacoglossa (Mollusca, Gastropoda, Opisthobranchia)". Philosophical Transactions of the Rpyal Society London B Biological Sciences 351(1335 ): 91-122. doi:10.1098/rstb.1996.0006.
- ^ Händeler K., Grzymbowski Y. P., Krug P. J. & Wägele H. (2009) "Functional chloroplasts in metazoan cells - a unique evolutionary strategy in animal life". Frontiers in Zoology 6: 28. doi:10.1186/1742-9994-6-28.
- ^ Rudman W. B. 2001 (October 4). Julia exquisita (Gould, 1862). Sea Slug Forum. Australian Museum, Sydney, accessed 10 May 2009.
- ^ http://www.19thcenturyscience.org/HMSC/HMSC-Reports/Zool-35/PDFpages/-13-35.html http://www.19thcenturyscience.org/HMSC/HMSC-Reports/Zool-35/PDFpages/13-35-273.pdf http://www.19thcenturyscience.org/HMSC/HMSC-Reports/Zool-35/PDFpages/13-35-274.pdf (dead link), accessed 7 December 2008
- ^ a b c Robert F. Bolland. 2001. OKINAWAN OPISTHOBRANCH OF THE WEEK Julia exquisita. Last change of the page 12 March 2001.
- ^ http://www.poppe-images.com/images/search_results.php?family=JULIIDAE accessed 11 May 2009
- ^ Pittman C. 2001 (October 10). Julia zebra Kawaguti, 1981. Sea Slug Forum. Australian Museum, Sydney, accessed 10 May 2009.
- ^ Kawaguti S. 1981. A new bivalved gastropod Julia zebra. Bulletin of the Kawasaki Paramedical College, 1: 9-13.
- ^ Michael D. Miller. 2002. Berthelinia chloris. The Slug Site, accessed 11 May 2009.
- ^ Cory Pittman & Pauline Fiene. 2009. Berthelinia pseudochloris. Sea Slugs of Hawaii, last change of the page 27 January 2009, accessed 10 May 2009.
- ^ Burn, R. F. 1965. Rediscovery and taxonomy of Edenttellina typica Gatliff and Gabriel. Nature, 206(4985): 735-736.
- ^ Rudman W. B. 2002 (March 11). Tamanovalva limax Kawaguti & Baba, 1959. Sea Slug Forum. Australian Museum, Sydney, accessed 10 May 2009.
- ^ Gatliff J. H. & Gabriel C. J. 1911. On some new species of Victorian marine mollusca. Proceedings of the Royal Society of Victoria, 24: 189-192.
- ^ Rudman W. B. 2001 (October 16). Edenttellina typica Gatliff & Gabriel, 1911. Sea Slug Forum. Australian Museum, Sydney, accessed 10 May 2009.
- ^ Rudman W. B. 2001 (October 16). Midorigai australis Burn, 1960. Sea Slug Forum. Australian Museum, Sydney, accessed 10 May 2009.
External links
| Wikimedia Commons has media related to: Juliidae |
- Cory Pittman & Pauline Fiene. 2009. Juliidae. Sea Slugs of Hawaii.
- Images of 4 species of Juliidae in Japan
- Photos of Julia exquisita at Sea Slug Forum
- Detailed photos of the shell of Julia exquisita at Sea Slug Forum
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