Nitzschia transtagensis E.Morales, Novais, C.E.Wetzel, Morais & L.Ector, 2019

Cid-Rodriguez, Maria, Gonzalez-Paz, Lorena & Delgado, Cristina, 2024, Nitzschia transtagensis Morales, Novais, Wetzel, Morais & Ector (Bacillariophyceae) - the second record in the Mediterranean Region, Biodiversity Data Journal 12, pp. 115601-115601 : 115601

Nitzschia transtagensis E.Morales, Novais, C.E.Wetzel, Morais & L.Ector, 2019

Materials

Type status: Other material. Occurrence: occurrenceDetails: https://www.tandfonline.com/doi/abs/10.1080/23818107.2019.1688676; recordedBy: Cristina Delgado; individualCount: 2.6%; associatedReferences: https://www.tandfonline.com/doi/abs/10.1080/23818107.2019.1688676; occurrenceID: F74F768A-9684-5D9C-A211-BFEA371756D9; Location : continent: Europe ; waterBody: Temporay streams from Balearic Isands ; islandGroup: Balearic Islands; island: Majorca ; country: Spain; countryCode: ES; stateProvince: Majorca ; county: Spain; municipality: Artà; Event : samplingProtocol: Light microscope count; year: 2005; habitat: Temporary stream

Description

Frustules with apical asymmetry with an undulated pattern on the secondary side (Fig. 2 ). Valves 34.6-40.0 μm long, 4.0-5.3 μm wide and fibula density 8-11/10 μm (n = 13). It is noteworthy that striae are visible with LM in some specimens. Directing attention to the images in Figure 2, we highlight the species distinctive characteristics, including a convex primary (raphe) side with a slight undulated abvalvar edge of the mantle and clearly undulated secondary valve side. We believe the debris surrounding the Nitzschia specimens may be attributed to the calcareous geology of Majorca. In the studied samples, Nitzschia transtagensis frustules were observed with length and width measurements consistent to those of the type material described by Morales et al. (2019), but with a higher fibulae density 8-11 in 10 µm compared to 6-10 in 10 µm reported by Morales et al. (2019).

Distribution

Nitzschia transtagensis was found in a single sample collected from the Torrent des Castellot Mountain stream located in the Artá Municipality, northeast of the Majorca Island (Balearic Islands), coordinates 39° 44' 16.24" N, 3° 24' 30.07" W (Fig. 1 ). This stream was sampled during the autumn of 2005 and spring of 2006. The Torrent des Castellot Mountain stream is a tributary of the Torrent de sa Font des Pí, which flows into Cala Torta, NE of Majorca Island. Notably, Nitzschia transtagensis only occurred in one of the two samples collected from the Torrent des Castellot Mountain stream, accounting for an abundance of 2.6%. Nitzschia transtagensis Morales, Novais, Wetzel, Morais & Ector was exclusively found in the sample collected in autumn of 2005 from this specific locality. We visited the same location in May 2006 and in March and May 2008 to determine if the taxon was there, but it was impossible to take samples because the stream was dry.

Ecology

Nitzschia transtagensis was present in oligotrophic waters (0.052 mg∙l-1 of nitrate), with slightly alkaline pH values (7.8) and medium water conductivity (626.5 µS cm-1). The values of these chemical parameters measured in May 2006 are provided in Table 1 . The IPS index was 18.7 (over a maximum of 20) and the value of Shannon-Wiener (H ') diversity index was 2.26 (Table 2 ). Within the diatom assemblage where N. transtagensis was found, a total of 20 different diatom species were identified. These species were: Achnanthidium minutissimum ( Kützing) Czarnecki (39.2%) (Fig. 3 a-e), Gomphonema rosenstockianum Lange-Bertalot & Reichardt (28.9%) (Fig. 3 f-l), Halamphora oligotraphenta (Lange-Bertalot) Levkov (20.4%) (Fig. 3 m-r), Navicula cryptotenella Lange-Bertalot (2.3%), Navicula sp. 2 (1.6%), Navicula cincta (Ehrenberg) Ralfs (0.7%), Craticula halophila (Grunow) D.G.Mann (0.5%), Diploneis oblongella ( Nägeli ex Kützing) A. Cleve (0.5%), Halamphora montana (Krasske) Levkov (0.5%), Nitzschia frustulum ( Kützing) Grunow (0.5%), Navicula veneta Kützing (0.5%), Encyonopsis microcephala (Grunow) Krammer (0.2%), Cymbella vulgata Krammer (0.2%) (Fig. 3 s-w), Encyonopsis cesatii (Rabenhorst) Krammer (0.2%), Fragilaria rumpens ( Kützing) G.W.F.Carlson (0.2%), Gomphonema sp. Ehrenberg (0.2%), Luticola goeppertiana (Bleisch) D.G.Mann ex Rarick, S.Wu, S.S.Lee & Edlund (0.2%), Navicula sp. (0.2%) and Navicula genus Bory (0.2%). In the sample collected in the spring of 2006, where N. transtagensis was not present, water temperature and electrical conductivity were higher (14.3 ºC and 938.9 µS cm-1) and the assemblage was less diverse, being mainly dominated by A. minutissimum (92.3%) and H. oligotraphenta (3.8%).

Figures

Figure 1. Map of the island of Majorca showing the location of Torrent des Castellot (black circle). The left side shows its location within Spain.

Figure 2. Light micrographs of Nitzschia transtagentis Morales, Novais, Wetzel, Morais & Ector, found in a torrent of Castellot (Majorca Island). Scale bar = 10 μm.

Figure 3. Light micrographs. a-e Achnanthidium minutissimum (Kuetzing) Czarnecki; f-l Gomphonema rosenstockianum Lange-Bertalot & Reichardt; m-r Halamphora oligotraphenta (Lange-Bertalot) Levkov; s-w Cymbella vulgata Krammer. Scale bar = 10 μm.