Amphilonche elongata
| Amphilonche elongata | |
|---|---|
 | |
| Light microscopy images of A. elongata specimen from the Red Sea (Gulf of Eilat) (scale bars = 50 µm). | |
Scientific classification  | |
| Domain: | Eukaryota |
| Clade: | Sar |
| Clade: | Rhizaria |
| Phylum: | Radiolaria |
| Class: | Acantharia |
| Order: | Symphiacanthida |
| Family: | Acanthometridae |
| Genus: | Amphilonche |
| Species: | A. elongata |
| Binomial name | |
| Amphilonche elongata (Muller, 1858)[1] | |
Amphilonche elongata is a species in the protistan class Acantharia, a group of marine microorganisms belonging to the Rhizaria supergroup. Acantharians are characterized by their intricate celestine skeletons or "tests". Because of these structures' fragility and proclivities to dissolve in preserved samples,[2] much information is still to be learned about A. elongata including how they are physiologically and energetically able to form and maintain their dense tests.
Taxonomy and evolution
A. elongata is a sister group to Phyllostaurus siculus,[3][4] as determined by 18S rDNA sequencing. Both species belong to Acantharia's clade F, which is classified through their morphological traits, vertical distribution, and reproductive strategies.[3] However, at least two distinct ribotypes have been identified in A. elongata, and three subspecies have been described.[5][6] This information suggesting genetic diversity and/or potential cryptic speciation should be an area of future research.
Morphology
The species' latin name elongata refers to the organism's elongated shape.[7] A single spine is found on each distal end of the central capsular shell. This shell is observed as smooth in texture and with invisible pores throughout.[8] In the middle are sets of longer primary and shorter secondary spicules and, within the periplasmic cortex, are up to two dozen myonemes for organisms in this genus.[9] These structures are contractile and could be potentially used for locomotion or prey capture.
Distribution
This is a common and cosmopolitan species in both neritic (coastal) and oceanic (open ocean) regions[9] with abundances that appear to peak in spring[10] and reach its lowest numbers off the coast in summer and autumn.[9]
Amphilonche elongata has been found in both the epipelagic 0–200 m (0–656 ft) and, in younger developmental stages, the upper mesopelagic 200–500 m (660–1,640 ft). Their absence at greater depths is possibly due to lack of survival below the oxygen minimum zone and/or a physiological need to retain algal endosymbionts which limit them to the photic zone.[2] Additionally, vertical niche partitioning has been documented in acantharian species, suggesting competition may also drive distribution in the water column.
Ecology
Clade E and F acantharians are those that diverged more recently, have rigid skeletons, and tightly joined spicules. Because of their morphology, they reproduce via instant "swarmers" in contrast to the other groups which develop cysts that sink into the lower mesopelagic before releasing the swarmer cells.[3] These adaptations are each associated with the presence of photosynthetic symbiotic microalgae. A. elongata is exclusively witnessed with Phaeocystis endosymbionts.[11]
References
- ↑ WoRMS. "Amphilonche elongata (Müller, 1858)". World Register of Marine Species. Retrieved 14 August 2025.
- 1 2 Michaels, A. F. (1988-04-01). "Vertical distribution and abundance of Acantharia and their symbionts". Marine Biology. 97 (4): 559–569. Bibcode:1988MarBi..97..559M. doi:10.1007/BF00391052. ISSN 1432-1793.
- 1 2 3 Decelle, Johan; Probert, Ian; Bittner, Lucie; Desdevises, Yves; Colin, Sébastien; de Vargas, Colomban; Galí, Martí; Simó, Rafel; Not, Fabrice (2012-10-30). "An original mode of symbiosis in open ocean plankton". Proceedings of the National Academy of Sciences. 109 (44): 18000–18005. Bibcode:2012PNAS..10918000D. doi:10.1073/pnas.1212303109. PMC 3497740. PMID 23071304.
- ↑ He, Ding; Sierra, Roberto; Pawlowski, Jan; Baldauf, Sandra L. (2016-08-01). "Reducing long-branch effects in multi-protein data uncovers a close relationship between Alveolata and Rhizaria". Molecular Phylogenetics and Evolution. 101: 1–7. Bibcode:2016MolPE.101....1H. doi:10.1016/j.ympev.2016.04.033. ISSN 1055-7903. PMID 27132173.
- ↑ Decelle, Johan; Romac, Sarah; Sasaki, Eriko; Not, Fabrice; Mahé, Frédéric (2014-08-04). "Intracellular Diversity of the V4 and V9 Regions of the 18S rRNA in Marine Protists (Radiolarians) Assessed by High-Throughput Sequencing". PLOS ONE. 9 (8) e104297. Bibcode:2014PLoSO...9j4297D. doi:10.1371/journal.pone.0104297. ISSN 1932-6203. PMC 4121268. PMID 25090095.
- ↑ Fauna e flora del Golfo di Napoli: Monografia della Stazione zoologica di Napoli (in German). Springer-Verlag. 1880.
- ↑ Froese, Rainer; Pauly, Daniel (eds.). "Barbucca elongata". FishBase. Retrieved 2025-02-27.
- ↑ Munir, Sonia; Sun, Jun; Morton, Steve L. (2021). "The First Record and Classification of Planktonic Radiolarian (Phylum Retaria) and Phaeodarian (Phylum Cercozoa) in the Eastern Indian Ocean". Biology. 10 (3): 202. doi:10.3390/biology10030202. ISSN 2079-7737. PMC 8002099. PMID 33800496.
- 1 2 3 Lakkis, S. (1971-11-01). "Contribution à l'étude du zooplancton des eaux libanaises". Marine Biology (in French). 11 (2): 138–148. Bibcode:1971MarBi..11..138L. doi:10.1007/BF00348763. ISSN 1432-1793.
- ↑ Delrio, G.; Merinfeld, G. "Study of Selective Absorption of Strontium by Anatomists (February 1963-March 1964)". PARLESA DU STRONTIUM - Rapport Annuel.
- ↑ Decelle, Johan; Siano, Raffaele; Probert, Ian; Poirier, Camille; Not, Fabrice (2012-12-01). "Multiple microalgal partners in symbiosis with the acantharian Acanthochiasma sp. (Radiolaria)". Symbiosis. 58 (1): 233–244. Bibcode:2012Symbi..58..233D. doi:10.1007/s13199-012-0195-x. ISSN 1878-7665.