Research Article |
Corresponding author: Ralitsa Zidarova ( zidarova.r@gmail.com ) Academic editor: Bing Liu
© 2022 Ralitsa Zidarova, Plamen Ivanov, Nina Dzhembekova, Myriam de Haan, Bart Van de Vijver.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Zidarova R, Ivanov P, Dzhembekova N, de Haan M, Van de Vijver B (2022) Two new Halamphora (Bacillariophyta) species from the marine coasts off Livingston Island, Antarctica. PhytoKeys 195: 161-174. https://doi.org/10.3897/phytokeys.195.81632
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During a survey of the marine benthic diatom flora on the coasts off Livingston Island (South Shetland Islands, Maritime Antarctic Region), two Halamphora species that could not be identified based on the currently available literature, were observed. Detailed light and scanning electron microscopy observations and thorough comparison with similar taxa in the literature revealed that both taxa should be described as new species. The first taxon, Halamphora kenderoviana sp. nov., was most likely misidentified in past Antarctic studies, and included within the range of another taxon, Halamphora coffeaeformis. Analysis of literature data showed that the second new taxon, Halamphora moncheviana sp. nov., has been previously reported from the Antarctic Continent (but as an unidentified species). The new taxa are compared with similar Halamphora taxa worldwide. Data on their ecology and distribution are also provided.
Amphora sensu lato, diatoms, marine benthos, taxonomy
In the past two decades considerable effort has been undertaken to improve our understanding of the diversity, species identities and distribution of the terrestrial and freshwater diatoms (Bacillariophyta) in the Antarctic realm (
The present paper describes two new marine species in the genus Halamphora (Cleve) Levkov, observed in several recently collected samples from the coasts off Livingston Island, part of the archipelago of the South Shetland Islands (Maritime Antarctic Region).
The genus Halamphora (Cleve) Levkov, originally described in 1895 by Cleve as a subgenus of Amphora Ehrenb. ex Kütz., was raised to genus level in 2009 (
Livingston Island is the second largest of the South Shetland Islands, located ca. 130 km north of the Antarctic Peninsula (Fig.
Sample | Date | pH | Salinity, PSU | Conductivity, mS/cm | О2, % | О2, mg.L-1 | Water Т, ОC |
---|---|---|---|---|---|---|---|
MO’ | 21/12/2018 | 8.4 | 33.1 | 52.2 | n/a | n/a | 5.5 |
LT10 | 04/02/2020 | n/a | 6.5 | 11.5 | 126.0 | 11.6 | 18.8 |
Map showing the position of Livingston Island relative to the Antarctic Peninsula (A), and the locations of the sampling sites (B, triangles). Map outlines are based on OpenStreetMap contributors (www.openstreetmap.org), edited and arranged using Adobe Illustrator and Adobe Photoshop. Scale bar: 2 km (B).
For light microscopy (LM), diatom samples were prepared following the method of
Systematics follows the adopted in DiatomBase (
Phylum Bacillariophyta Haeckel
Class Bacillariophyceae Haeckel
Family Amphipleuraceae Grunow
Slide BR-4681, Fig.
Halamphora kenderoviana sp. nov., valves from the type population from South Bay, Livingston Island A–I valves under LM, with fig. A showing an entire frustule D represents the holotype J two valves under SEM externally with details of the central raphe endings and mantle areolae K SEM of an entire valve internally L SEM of a valve internally, showing the prominent raised costae between the striae and the internal areolar occlusions M SEM of an entire valve externally, with a view on the mantle and the dorsal ridge. Scale bars: 10 µm (A–I, M); 5 µm (J–L).
Slide 401, University of Antwerp, Belgium.
Antarctica, Livingston Island, South Bay, Mongolian (Reserve) Port, small pool on a coastal rock during low tide, epilithon. 62°38'50"S, 60°22'26"W. Sample MO’, leg. R. Zidarova, coll. date 21 Dec. 2018.
LM description
(Fig.
SEM description
(Fig.
The new species is named after our colleague Dr Lyubomir Kenderov, hydrobiologist at the Faculty of Biology, University of Sofia, with whom RZ shared two Antarctic seasons, and who was often a helping hand during field work in Antarctica.
Halamphora kenderoviana was typically observed in tidal pools (
Slide BR-4682, Fig.
Halamphora moncheviana sp. nov., valves from the type population from South Bay A–H LM views of several valves G represents the holotype I SEM of an entire valve externally, showing the dorsal striae and the raphe endings J SEM, detail of the areolae externally, showing the recessed porous foramina K SEM, detail of the striae and areolae internally, showing the porous internal areolar foramina L SEM of an entire valve internally M SEM, external view of a valve with areolae arranged in longitudinal lines, most likely in a state of development. Scale bars: 10 µm (A–H); 5 µm (I, L, M); 1 µm (J, K).
Slide 400, University of Antwerp, Belgium.
Antarctica, Livingston Island, Hannah Point, small pool on a coastal rock north of the penguin rookeries, epilithon. 62°38'30"S, 60°36'32"W. Sample LT10, leg. R. Zidarova, coll. date 04 Feb. 2020.
LM description
(Fig.
SEM description
(Fig.
The new species is named after Prof Dr Snejana Moncheva, phycologist and former Director of the Institute of Oceanology at the Bulgarian Academy of Sciences, to thank her for considering our (RZ, NDzh) employment and career possibilities at the Institute.
Halamphora moncheviana was most abundant in the epilithon of a small coastal pool, having a relatively low salinity (6.5 PSU, sample LT10, Table
Based on the observed set of morphological features of H. kenderoviana and H. moncheviana, both these species from the coasts of Livingston Island clearly belong to the genus Halamphora, as defined in
Halamphora kenderoviana is one of the many Halamphora species, having a valve outline with protracted apices and biseriate striae, similarly to Halamphora coffeaeformis and its related taxa (
The most similar taxa in LM in terms of valve outline and striation pattern include Halamphora nagumoi Stepanek et al. and H. banzuensis Stepanek et al. However, under SEM, H. nagumoi, described from the Pacific coasts, presents very closely positioned central raphe endings and a prominent dorsal ridge (
Halamphora moncheviana, showing internally rectangular areolar openings arranged in regular rows, and externally irregular longitudinal lines on the dorsal side in LM, can hardly be confused with any other Amphora or Halamphora taxa. In valve outline, with its shortly protracted subcapitate apices, it bears only a slight resemblance to the South American brackish species Halamphora mira (Krasske) Levkov. The latter is a much larger taxon, with a length exceeding 35 µm, a width above 9 µm, and with a strongly arched raphe (
Two other marine taxa, Amphora antarctica Hust. (
Analyses were conducted within Contracts 80-10-239/2018 and 70.25-175/2019 with the National Center for Polar Studies, Bulgaria. Logistic support for the field work was provided by the Bulgarian Antarctic Institute. All members of the 27th and 28th Bulgarian Antarctic Expeditions are greatly acknowledged for their help during field work at South Bay, Livingston Island. LM observations were conducted at Olympus BX51 at the Institute of Biodiversity and Ecosystem Research (Bulgarian Academy of Sciences), and SEM micrographs were taken at Meise Botanic Garden, Belgium. We thank David M. Williams and Regine Jahn for their valuable comments on this manuscript.