New and Interesting Taxa from the Diatom Genus Gomphonema Ehrenberg in Shallow, Nearshore Sites on the Eastern Coast of Lake Baikal

Abstract

During this investigation, sixteen species from the genus Gomphonema were found in a shallow bay (near Oimur, Kabansky District) located on the eastern shore of Lake Baikal. Eleven of these taxa have been described previously. Five species are described as new to science. We provide ecological information about these Gomphonema species, including their distribution within and outside Lake Baikal, and compare and contrast the new taxa with morphologically similar congeners. The diversity of morphologies present in Lake Baikal among the Gomphonema species suggests there has been both in-lake speciation as well as the introduction of various groups of species. The idea that Lake Baikal may support a high number of endemics by their partitioning niches based on depth is supported by the different groups of gomphonemoid diatoms present.

Keywords: Bacillariophyceae; Gomphonema; Lake Baikal; morphology; new species; systematics; taxonomy.

Figure 1

(A–O). Gomphonema spp. Light microscopy, differential interference contrast, size diminution series. (A–F). G. makarovae. Slide no. 18589. (G–O). G. subarcticum. Slide no. 18599. Scale bar = 10 μm.

Figure 2

(A–N). Gomphonema distans. Light microscopy, differential interference contrast, size diminution series. Slide no. 18606. Scale bar = 10 μm.

Figure 3

(A–N). Gomphonema spp. Light microscopy, differential interference contrast, size diminution series. (A–H). G. demersum. Slides no. 18589 and 18606. (I–L). G. parvulius. Slides no. 18589 and 18599. (M,N). G. duplipunctatum. Slides no. 18599 and 18606. Scale bar = 10 μm.

Figure 4

(A–R). Gomphonema sphenovertex. Light microscopy, differential interference contrast, size diminution series. Slide no. 18606. Scale bar = 10 μm.

Figure 5

(A–R). Gomphonema jergackianum. Light microscopy, differential interference contrast, size diminution series. Slides no. 18589 and 18599. Scale bar = 10 μm.

Figure 6

(A–T). Gomphonema popovae. Light microscopy, differential interference contrast, size diminution series. Slide no. 18589. Scale bar = 10 μm.

Figure 7

(A–O). Gomphonema medioasiae. Light microscopy, differential interference contrast, size diminution series. Slide no. 18599. Scale bar = 10 μm.

Figure 8

(A–R). Gomphonema pseudoaugur Lange-Bertalot (A–L). Light microscopy, differential interference contrast, size diminution series. Slide no. 18599. (M–P). Scanning electron microscopy, external views. Scale bar (A–L) = 10 μm; (M) = 5 μm; (N) = 2 μm; (O–R) = 1 μm.

Figure 9

(A–D). Gomphonema pseudoaugur Lange-Bertalot. Scanning electron microscopy, internal views. (B). The black arrow shows the septum. (D). The black arrow shows the pseudoseptum. Scale bar (A) = 2 μm; (B–D) = 1 μm.

Figure 10

(A–Q). Gomphonema baicalodemersum Kulikovskiy, Kociolek, Solak and Glushchenko sp. nov. (A–Q). Light microscopy, differential interference contrast, size diminution series. Slide no. 18589. (R–T). Scanning electron microscopy, external views. (U,V). Scanning electron microscopy, internal views. (D). Holotype. Scale bar (A–Q) = 10 μm; (S) = 6 μm; (T) = 3 μm; (S,U,V) = 1 μm.

Figure 11

(A–H). Gomphonema genkalii Kulikovskiy, Kociolek, Solak and Glushchenko sp. nov. (A–F). Light microscopy, differential interference contrast, size diminution series. Slide no. 18607. (G,H). Scanning electron microscopy, internal views. (B). Holotype. Scale bar (A–F) = 10 μm; (H) = 6 μm; (G) = 2 μm.

Figure 12

(A–H). Gomphonema trifonovae Kulikovskiy, Kociolek, Solak and Glushchenko sp. nov. (A–E). Light microscopy, differential interference contrast, size diminution series. Slide no. 18608. (F,G). Scanning electron microscopy, external views. (H). Scanning electron microscopy, internal view. (C). Holotype. Scale bar (A–E) = 10 μm; (F,G) = 1 μm; (H) = 1 μm.

Figure 13

(A–O). Gomphonema zapitaja Kulikovskiy, Kociolek, Solak and Glushchenko sp. nov. (A–O). Light microscopy, differential interference contrast, size diminution series. Slide no. 18599 (A–E,G,H,J–O) and 18606 (F,I). (P–U). Scanning electron microscopy, external views. (V–X). Scanning electron microscopy, internal view. (B). Holotype. Scale bar (A–O) = 10 μm; (P,W,X) = 5 μm; (Q) = 2 μm; (R–V) = 1 μm.

Figure 14

(A–G). Gomphonema megabaicalensis Kulikovskiy, Kociolek, Solak and Glushchenko sp. nov. (A–C). Light microscopy, differential interference contrast, size diminution series. Slide no. 18609. (D–G). Scanning electron microscopy, external views. (A). Holotype. Scale bar (G) = 20 μm; (A–C) = 10 μm; (E,F) = 5 μm; (D) = 2 μm.

Figure 15

(A–C). Gomphonema megabaicalensis Kulikovskiy, Kociolek, Solak and Glushchenko sp. nov. Scanning electron microscopy, internal views. Scale bar (A) = 10 μm; (B,C) = 2 μm.