Acanella
- Dataset
- A taxonomic review of the genus Acanella (Cnidaria: Octocorallia: Isididae) in the North Atlantic Ocean, with descriptions of two new species
- Rank
- GENUS
Classification
- kingdom
- Animalia
- phylum
- Cnidaria
- class
- Anthozoa
- order
- Alcyonacea
- family
- Isididae
- genus
- Acanella
description
Description: Colonies bush-like with primary branching at the node, dichotomous in older parts of the colony and whorls of one to three on the secondary branches. Where collected holdfasts were round. Internodes white in color, 1 – 2 cm in length, and weakly longitudinally ribbed; main axis internodes at base of colony thickened and overgrowing nodes. Anastomosis of branches was not observed. Nodes are dark brown to black. Axis covered by light brown to dark brown coenenchyme when preserved. Coenenchymal sclerites 225 – 600 µm (n = 100; mean = 365 µm ± 0.02 µm) length, needle-like and covered with small spines. Polyps when preserved in ethanol are light brown to dark brown in color. Polyps small (1 ̄ 1.2 mm; n = 80; mean = 1.11 mm ± 0.02 mm) and squat (0.6 – 0.8 mm; n = 90; mean = 0.67 mm ± 0.02 mm) with a cylindrical shape that is slightly wider at the distal end compared to the proximal end. Polyps 2 mm apart on secondary branches, scarce on primary branch. Polyps arise 30 ° ̄ 45 ° from axis and are loosely biserially arranged on branch. Sclerites of polyp body predominantly short and needle-like (Figure 9) and range in length from 150 ̄ 250 µm (n = 100; mean = 167 µm ± 0.02 µm); 1 ̄ 2 needle-like, polyp-size sclerites (1 ̄ 1.5 mm; n = 60; mean = 1.23 mm ± 0.04 mm) may be found on the abaxial side of polyps and protrude between tentacles. Sclerites arranged longitudinally or obliquely up polyp body. Tentacular sclerites consist of small rods with small spines ranging from 150 ̄ 350 µm (n = 100; mean = 157 µm ± 0.01 µm). DNA sequences derived from mtMusS - 5 ’ (GenBank accession # KX 270220) and 18 S (KX 270213) differ from other the other Pacific Acanella Haplotypes by at least 0.10 % (2 nucleotide substitutions across 1955 sites).
discussion
Remarks: Colonies with Haplotype D most closely resemble A. dispar based on polyp and sclerite morphology (Figure 9). In particular, these colonies have long sclerites restricted to one side of the polyp; however, Bayer (1990) described these elongate needles as being abaxial in A. dispar, whereas in the colonies we examined and sequenced, the elongate needles are found adaxial or abaxial depending on curvature of the polyp. Bayer’s (1990) A. dispar were collected in the Hawaiian Islands whereas the colonies with Haplotype D came from the southwestern Pacific Ocean near New Caledonia, albeit in the same depth range as A. dispar (Figure 3). To be conservative, we have chosen not to definitively assign these samples to A. dispar pending further analysis. Among the Acanella Haplotypes, C (A. chiliensis) and D (A. cf. dispar) are the closest genetically, with only two substitutions (in mtMutS- 5 ’) between them. They both differ from the hypothesized transitional sequence by the same seven substitutions (Figure 2) and have overlapping distributions and depth ranges. Although sequence Haplotypes C and D have low genetic distance between them and colonies overlap in geographic distribution, the polyp morphology of the two species is very different.
distribution
Distribution: North and west of New Caledonia, 360 ̄ 550 m depth.
materials_examined
Material examined: Collected via trawl aboard R / V Alis, north of New Caledonia. - 21.7333 166.633, 383 ̄ 385 m depth, 5 September 2011, Station CP 3810 Specimen ID EXB 38101. Deposited in the Muséum national d'Histoire naturelle; MNHN-IK- 2011 - 1004. Collected via trawl aboard R / V Alis, west of New Caledonia. - 22.2498 167.2170, 390 ̄ 410 m depth, 25 October 2008, Station CP 3089, Specimen ID TER 10037. Deposited in the Muséum national d'Histoire naturelle; MNHN-IK- 2008 - 1760. GenBank accession # KX 270220, KX 270213. - 22.1912 167.1593, 360 ̄ 380 m depth, 25 October 2008, Station CP 3092, Specimen ID TER 10063, TER 10064, TER 10065, TER 30921. Deposited in the Muséum national d'Histoire naturelle; MNHN-IK- 2008 - 1765, MNHN-IK- 2008 - 1764, MNHN-IK- 2008 - 1762, MNHN-IK- 2011 - 1003. - 22.4672 167.4843, 440 ̄ 550 m depth, 24 October 2008, Station DW 3080, Specimen ID TER 9039. Deposited in the Muséum national d'Histoire naturelle; MNHN-IK- 2008 ̄ 1835.
Name
- Homonyms
- Acanella Gray 1870
- Acanella
- Acanella