Actiniaria of the southwestern Atlantic Ocean. II. Sagartiidae and Metridiidae

Riemann-Zürneck, Karin

doi:10.1007/bf01611687

“…Given the transient nature and low frequency of fighting tentacles in populations of species that possess them (e.g., Hand, 1956;Williams, 1975), we agree with others (e.g., Hand, 1956;Riemann-Zürneck, 1975;Williams, 1975;Manuel, 1981; den Hartog and Ates, 2011) and recommend that presence of fighting tentacles be taken in combination with other characters to more effectively distinguish members of Diadumenidae from other metridioidean families. Nevertheless, we maintain the presence of fighting tentacles in the diagnosis of family Diadumenidae given its uniqueness within Actiniaria, as a way to help identify species that exhibit them.…”

Section: Discussionsupporting

confidence: 79%

Sea anemones through X-rays : visualization of two species of Diadumene (Cnidaria, Actiniaria) using micro-CT

Gusmão¹,

Grajales²,

Rodríguez³

2018

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Diadumenidae is a monogeneric family comprised of 10 valid species in the genus Diadumene. Although these species are distributed in all but the Southern Ocean, Diadumene lineata is a cosmopolitan species and one of the most widely distributed marine organisms. Recent phylogenetic analyses with multiple species have recovered Diadumenidae as a monophyletic group with high support. Although generic placement is straightforward, species-level identifications within Diadumene are difficult because species are defined by a mosaic of characters that vary in degree rather than kind. Two species of the genus have been recorded in the southwestern Atlantic: D. paranaensis along the south coast of Brazil and D. lineata along the southeast and northeast coasts of Brazil as well as in Argentina. Here we record D. leucolena for the first time in the southern hemisphere and describe D. manezinha, sp. nov., raising to four the number of species of Diadumene for Brazil and to 11 worldwide. We incorporated microcomputed tomography (micro-CT) into the description of both species in the first application of the method for Actiniaria. We evaluate the utility of micro-CT imaging and its potential to generate fast, low-cost, and high-resolution datasets despite the anemone's low-density soft tissue. We present a protocol for sample handling, chemical staining, and scanning parameters that resulted in satisfactory imaging of the two specimens examined. We also analyze advantages and limitations of using micro-CT over traditional techniques in the study of sea anemones.

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“…Given the transient nature and low frequency of fighting tentacles in populations of species that possess them (e.g., Williams, 1975), we agree with others (e.g., Riemann-Zürneck, 1975;Williams, 1975;Manuel, 1981;den Hartog and Ates, 2011) and recommend that presence of fighting tentacles be taken in combination with other characters to more effectively distinguish members of Diadumenidae from other metridioidean families. Nevertheless, we maintain the presence of fighting tentacles in the diagnosis of family Diadumenidae given its uniqueness within Actiniaria, as a way to help identify species that exhibit them.…”

Section: Discussionsupporting

confidence: 76%

“…In addition, the term "catch tentacles" of Carlgren (1929: Fangtentakeln) has been replaced by "fighting tentacles" to better reflect their searching and intraspecific agonistic behavior rather than feeding (Purcell, 1977;Williams, 1975;Fukui, 1986;Häussermann, 2003;Kovtun et al, 2012). Although fighting tentacles are not present in all species of Diadumenidae and many have warned against using them as a taxonomic character (e.g., Riemann-Zürneck, 1975), we chose to keep the presence of this character in the diagnosis given its uniqueness within Actiniaria and its presence in the type species of the genus (i.e., Diadumene schilleriana Stoliczka, 1869). We also specified that tentacles of first but sometimes also second cycles may form fighting tentacles and emphasized that they may be ephemeral even in species that possess them.…”

Section: Order Actiniaria Hertwig 1882mentioning

confidence: 99%

Sea Anemones through X-Rays: Visualization of Two Species ofDiadumene(Cnidaria, Actiniaria) Using Micro-CT

Gusmão

¹

,

Grajales

²

,

Rodríguez

³

2018

American Museum Novitates

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Diadumenidae is a monogeneric family comprised of 10 valid species in the genus Diadumene. Although these species are distributed in all but the Southern Ocean, Diadumene lineata is a cosmopolitan species and one of the most widely distributed marine organisms. Recent phylogenetic analyses with multiple species have recovered Diadumenidae as a monophyletic group with high support. Although generic placement is straightforward, species-level identifications within Diadumene are difficult because species are defined by a mosaic of characters that vary in degree rather than kind. Two species of the genus have been recorded in the southwestern Atlantic: D. paranaensis along the south coast of Brazil and D. lineata along the southeast and northeast coasts of Brazil as well as in Argentina. Here we record D. leucolena for the first time in the southern hemisphere and describe D. manezinha, sp. nov., raising to four the number of species of Diadumene for Brazil and to 11 worldwide. We incorporated microcomputed tomography (micro-CT) into the description of both species in the first application of the method for Actiniaria. We evaluate the utility of micro-CT imaging and its potential to generate fast, low-cost, and high-resolution datasets despite the anemone's low-density soft tissue. We present a protocol for sample handling, chemical staining, and scanning parameters that resulted in satisfactory imaging of the two specimens examined. We also analyze advantages and limitations of using micro-CT over traditional techniques in the study of sea anemones.

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“…Riemann-Zürneck synonymised the Chilean species Metridium parvulum McMurrich, 1904 andSagartia lobata Carlgren, 1899 with Metridium senile and created the subspecies M. senile lobatum. She then cited it for the Argentinean coast (Riemann-Zürneck, 1975;1986). This species inhabits the shallow water around the Peninsula Valdes (own observation) and around Buenos Aires (D. Lauretta, in litt., 2004).…”

Section: Overlaps Between the Western Patagonian And The Eastern Patamentioning

confidence: 99%

Distribution patterns of Chilean shallow-water sea anemones (Cnidaria: Anthozoa: Actiniaria, Corallimorpharia); with a discussion of the taxonomic and zoogeographic relationships between the actinofauna of the South East Pacific, the South West Atlantic and the Antarctic

Häussermann¹,

Försterra²

2005

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The first complete zoogeographical analysis of Chilean shallow water sea anemones (Actiniaria and Corallimorpharia) and their taxonomic relations with neighbouring faunas is provided, based on extensive recent sampling in combination with a literature review. Between 1994 and 2004, we collected more than 1000 specimens of 32 distinct species of Actiniaria and Corallimorpharia at more than 100 sites along the Chilean coast between Arica (18°30'S; 70°19'W) and the Straits of Magellan (53°36'S 70°56'W). Sampling was done in the intertidal during low tides and in the subtidal by means of SCUBA diving down to depths of 40 m. The northern part of the Chilean fjord region showed the highest number of species (23). Our results contradict an abrupt general change in the marine faunal composition at 42°S, instead showing the continuation of species of the exposed coast and the joining of fjord species due to the availability of additional habitats in the richly structured fjord region south of 42°S, and also to eurybathy. The southern distribution limits of the species we found in northern and central Chile show only one significant concentration around the Peninsula Taitao (approx. 48°S). This either indicates a zoogeographic barrier for shallow water species at the Peninsula Taitao, or is a sampling artifact caused by poor data from the region between the Peninsula Taitao and the Straits of Magellan. According to the literature, 18 of the 63 described Chilean sea anemones (Pacific Ocean) can also be found in Argentina (Atlantic Ocean) and 13 in the Antarctic. However, many records and statuses of the common species of the South East Pacific and the South West Atlantic/Antarctic are uncertain or doubtful and need revision or confirmation.

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Actiniaria of the southwestern Atlantic Ocean. II. Sagartiidae and Metridiidae

Abstract: Actiniaria of the southwestern Atlantic Ocean. II. Sagartiidae and Metridiidae.

Cited by 19 publications

References 5 publications

Sea anemones through X-rays : visualization of two species of Diadumene (Cnidaria, Actiniaria) using micro-CT

Sea anemones through X-rays : visualization of two species of Diadumene (Cnidaria, Actiniaria) using micro-CT

Sea Anemones through X-Rays: Visualization of Two Species ofDiadumene(Cnidaria, Actiniaria) Using Micro-CT

Distribution patterns of Chilean shallow-water sea anemones (Cnidaria: Anthozoa: Actiniaria, Corallimorpharia); with a discussion of the taxonomic and zoogeographic relationships between the actinofauna of the South East Pacific, the South West Atlantic and the Antarctic

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