Smithsonian Marine Station at Fort Pierce

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Figure 1.


Figure 2.

Species Name: Arcocellulus mammifer Hasle, von Stosch et Syvertsen
Common Name: None
Synonymy: None
  1. TAXONOMY

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Protista Bacillariophyta Mediophyceae - - Arcocellulus

    Species Description

    Cells are genuflexed in girdle view (Fig. 2, TEM) and heterovalvar.  The concave valve has two elongate spines (pili); the convex valve has none. The pili are strongly curved in relation to each other, originate at the valve apices, and have shorter branches arising near the proximal end.  There are numerous bands in the cingulum, which are split, alternate, and also are genuflexed (Round et al. 1990). Each band has a row of fine pores numbering about 250 in 10µm according to Hasle et al (1983).  Valves are elongate with a single row of marginal pores and a variable number of scattered additional pores on the valve surface that tend to be more numerous near the apices (Fig. 1). At each valve apex is a single slightly raised pore topped with an ocellulus (Hasle et al. 1983); pili originate at the proximal side of these raised pores. Near the valve center but somewhat displaced toward the margin is a rimoportula-like slit (Fig. 1) that appears not to rise above the cell surface.  Cells range from 2-12.5 µm in the apical axis (9-11µm seen in the IRL), 1.1-1.4 µm in the transapical axis, and 2-4 µm in the pervalvar axis (Hasle et al. 1983).  Poroids in the marginal rows number 39-45 in 10µm.  Shorter cells tend to be elliptical or subcircular. There is a single chloroplast.

    The species is well-known from the European coast, and is also reported from the Mediterranean Sea (Percopo et al. 2011). It is present in the Gulf of Mexico and along the U.S. East coast (PE Hargraves, personal observation).  It probably has a much wider distribution but is overlooked because of its small size, along with its congener, A. cornucervis Hasle, von Stosch et Syvertsen.  Little is known of its ecology; Round et al. (1990) describe the genus as ‘solitary or chain-forming, planktonic or benthic, marine.’ Hasle et al. (1983) report the presence of auxospores in culture at temperatures of 15ºC and 21ºC. The spatial and temporal occurrence of this species in the IRL is uncertain because it is easily overlooked, and because according to Hasle et al., the smaller cells lack pili, one of the definitive characteristics.  It was occasionally seen in the IRL between the Fort Pierce and St Lucie inlets, never in any abundance.

  2. HABITAT AND DISTRIBUTION

    No information is available at this time

  3. LIFE HISTORY AND POPULATION BIOLOGY

    No information is available at this time

  4. PHYSICAL TOLERANCES

    No information is available at this time

  5. COMMUNITY ECOLOGY

    No information is available at this time

  6. ADDITIONAL INFORMATION

    No information is available at this time

  7. REFERENCES

    Hasle GR, von Stosch HA, Syvertsen EE. 1983. Cymatosiraceae, a new diatom family. Bacillaria 6:9-156.

    Percopo I, Siano R, Cerino F, Sarno D, Zingone A. 2011. Phytoplankton diversity during the spring bloom in the northwestern Mediterranean Sea. Botanica Marina 54(3):243-267. DOI: http://dx.doi.org/10.1515/bot.2011.033.

    Round FE, Crawford RM, Mann DG. 1990. The Diatoms, Biology & Morphology of the Genera. Cambridge University Press, Cambridge. 747pp.

Unless otherwise noted, all images and text by PE Hargraves
Editing and page maintenance by LH Sweat
For questions, comments or contributions, please contact us at:
irl_webmaster@si.edu
Page last updated: 28 April 2015

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&nbs;p Arcocellulus mammifer

Smithsonian Marine Station at Fort Pierce

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Figure 1.


Figure 2.

Species Name: Arcocellulus mammifer Hasle, von Stosch et Syvertsen
Common Name: None
Synonymy: None
  1. TAXONOMY

    Kingdom Phylum/Division Class: Order: Family: Genus:
    Protista Bacillariophyta Mediophyceae - - Arcocellulus

    Species Description

    Cells are genuflexed in girdle view (Fig. 2, TEM) and heterovalvar.  The concave valve has two elongate spines (pili); the convex valve has none. The pili are strongly curved in relation to each other, originate at the valve apices, and have shorter branches arising near the proximal end.  There are numerous bands in the cingulum, which are split, alternate, and also are genuflexed (Round et al. 1990). Each band has a row of fine pores numbering about 250 in 10µm according to Hasle et al (1983).  Valves are elongate with a single row of marginal pores and a variable number of scattered additional pores on the valve surface that tend to be more numerous near the apices (Fig. 1). At each valve apex is a single slightly raised pore topped with an ocellulus (Hasle et al. 1983); pili originate at the proximal side of these raised pores. Near the valve center but somewhat displaced toward the margin is a rimoportula-like slit (Fig. 1) that appears not to rise above the cell surface.  Cells range from 2-12.5 µm in the apical axis (9-11µm seen in the IRL), 1.1-1.4 µm in the transapical axis, and 2-4 µm in the pervalvar axis (Hasle et al. 1983).  Poroids in the marginal rows number 39-45 in 10µm.  Shorter cells tend to be elliptical or subcircular. There is a single chloroplast.

    The species is well-known from the European coast, and is also reported from the Mediterranean Sea (Percopo et al. 2011). It is present in the Gulf of Mexico and along the U.S. East coast (PE Hargraves, personal observation).  It probably has a much wider distribution but is overlooked because of its small size, along with its congener, A. cornucervis Hasle, von Stosch et Syvertsen.  Little is known of its ecology; Round et al. (1990) describe the genus as ‘solitary or chain-forming, planktonic or benthic, marine.’ Hasle et al. (1983) report the presence of auxospores in culture at temperatures of 15ºC and 21ºC. The spatial and temporal occurrence of this species in the IRL is uncertain because it is easily overlooked, and because according to Hasle et al., the smaller cells lack pili, one of the definitive characteristics.  It was occasionally seen in the IRL between the Fort Pierce and St Lucie inlets, never in any abundance.

  2. HABITAT AND DISTRIBUTION

    No information is available at this time

  3. LIFE HISTORY AND POPULATION BIOLOGY

    No information is available at this time

  4. PHYSICAL TOLERANCES

    No information is available at this time

  5. COMMUNITY ECOLOGY

    No information is available at this time

  6. ADDITIONAL INFORMATION

    No information is available at this time

  7. REFERENCES

    Hasle GR, von Stosch HA, Syvertsen EE. 1983. Cymatosiraceae, a new diatom family. Bacillaria 6:9-156.

    Percopo I, Siano R, Cerino F, Sarno D, Zingone A. 2011. Phytoplankton diversity during the spring bloom in the northwestern Mediterranean Sea. Botanica Marina 54(3):243-267. DOI: http://dx.doi.org/10.1515/bot.2011.033.

    Round FE, Crawford RM, Mann DG. 1990. The Diatoms, Biology & Morphology of the Genera. Cambridge University Press, Cambridge. 747pp.

Unless otherwise noted, all images and text by PE Hargraves
Editing and page maintenance by LH Sweat
For questions, comments or contributions, please contact us at:
irl_webmaster@si.edu
Page last updated: 28 April 2015

[ TOP ]