Pinnularia baetica Fernández Moreno & Sánchez Castillo, 2020

Moreno, David Fernández, Luís, Ana T., Vidakovic, Danijela, Levkov, Zlatko & Sánchez Castillo, Pedro M., 2020, Pinnularia baetica sp. nov. (Bacillarophyceae): Comparison with other panduriform species in the Mediterranean area, Phytotaxa 435 (2), pp. 85-100 : 88-90

publication ID	https://doi.org/ 10.11646/phytotaxa.435.2.1
persistent identifier	https://treatment.plazi.org/id/584F0F7C-065B-FF8F-E3A4-DD35F877F9DC
treatment provided by	Felipe
scientific name	Pinnularia baetica Fernández Moreno & Sánchez Castillo
status

Treatment

Genus Pinnularia Ehrenberg (1843: 43–49)

Pinnularia baetica Fernández Moreno & Sánchez Castillo sp. nov. Figs 2–16 View FIGURES 2–16 , 47–52 View FIGURES 47–52 , 66–69 View FIGURES 66–76

Type:— SPAIN, province of Granada, Sierra Seca, Natural Park of Sierra de Castril, Laguna Seca, 37º56´41.86´´ N, 2º40´54.80´´ W, lagoon epipelon, Coll. David Fernández Moreno and Pedro Miguel Sánchez Castillo, 2007 (Holotype: Phycotheque GDA-algae slide number 3725, prepared with material from the sample collected in Laguna Seca, hosted in the Herbarium, University of Granada (Spain), Isotype: Slide BM 101919, prepared with material from the sample collected in Laguna Seca, hosted in the Natural History Museum, London ( UK).

Description

Valves panduriform ( Figs 2–16 View FIGURES 2–16 ), constricted in the center, then distally widening finishing with narrowly rounded to almost cuneate apices. Valve length 45.8–77.7 µm, width 9.6–12.2 µm (n=20). Central area variable, from narrow rhombic fascia (e.g. Fig. 6 View FIGURES 2–16 ) to broad bow-tie-shaped fascia (e.g. Fig. 12 View FIGURES 2–16 ), formed by shortening of one to three central striae. Fascia with similar size on both sides (e.g. Figs 4, 12 View FIGURES 2–16 ) or smaller on secondary side ( Figs 5, 6 View FIGURES 2–16 ). Axial area linear-lanceolate, widening towards central area. Raphe slightly lateral, with unilaterally deflected proximal raphe ends, terminating in slightly expanded pores ( Figs 2–16 View FIGURES 2–16 ). The distal raphe fissures hooked on opposite side of proximal ends. Transapical striae parallel to slightly radiate in mid-valve to convergent at the poles, 9–10 in 10 µm.

External proximal raphe ends slightly expanded and unilaterally deflected ( Figs 47, 51 View FIGURES 47–52 ), while distal raphe fissures clearly hooked shaped ( Figs 47, 49 View FIGURES 47–52 ), continuing onto mantle. Internal raphe straight, proximally terminating with short, slightly bent, on small inflated central nodule ( Fig. 48 View FIGURES 47–52 ). Distal raphe endings terminating onto small, slightly eccentric, weakly raised helictoglossa ( Figs 48, 50 View FIGURES 47–52 ). Striae composed of large alveolus ( Fig. 50 View FIGURES 47–52 ). Externally, each alveolus composed of 7–8 rows of small, round areolae ( Fig. 52 View FIGURES 47–52 ) with diameter of 75–100 nm. Each areola occluded by porous hymen perforated by 6/5 pores with 20–30 nm in diameter.

Etymology: The specific epithet baetica refers to the name of the mountain chain complex where the species was found.

Ecology The limnological characteristics of Laguna Seca at the sampling time, corresponded to the end of the flood period (in summer), when pond bottom became full of a community of macrophytes. The water temperature was 15.7°C, the conductivity was low (83 µS/cm), with a very alkaline pH of 9.2. The associated diatom flora from the littoral zone, together with P. baetica (12%) was dominated by Nitzschia tenuirostris Manguin (in Bourrelly & Manguin 1952: 105) (31%), Pinnularia cf. obscura Krasske (1932: 117) (32%) and species from Eunotia Ehrenberg (1837: 44) (2.5%) closely related to the taxa identified by Lange-Bertalot et al. (2003) in Sardinia, such as Eunotia sardiniensis Lange-Bertalot Cavacini, Tagliaventi & Alfinito (2003: 42) and Stauroneis Ehrenberg (1843: 45) (13%). In this study, species reported as P. atlasi ( Figs 17–31 View FIGURES 17–31 , 53–58 View FIGURES 53–58 ) were from the type locations designed by the original finder collected in Morocco (Ouiouane, Guedrouz) since Darley´s type material is unavailable. Valves are panduriform, constricted in the center, then distally widening and finishing with narrowly rounded to almost cuneate apices. Valve length of 35.4–77.9 µm and width 8.7–15.8 µm (n=37) in both locations. The central area is variable, from narrow rhombic fascia ( Fig. 27 View FIGURES 17–31 ) to broad bow-tie-shaped fascia ( Fig 18, 19 View FIGURES 17–31 ), formed sometimes by shortening central striae. Fascia with similar size on both sides ( Figs 17, 18 View FIGURES 17–31 ) or smaller on secondary side ( Fig. 27 View FIGURES 17–31 ). Axial area linear-lanceolate, widening towards the central area. Raphe slightly lateral, with unilaterally deflected proximal raphe ends, terminating in slightly expanded pores ( Figs 17–31 View FIGURES 17–31 ). The distal raphe fissures hooked on opposite side of proximal ends. Transapical striae are parallel to slightly radiate in mid-valve to convergent in poles, (9)10–11/10 µm. In North Macedonia just one valve of Pinnularia aff. atlasi ( Fig. 76 View FIGURES 66–76 ) was found, with sizes falling inside the Moroccans’ range but with length/width relation higher ( Table 2). Also, the spines are presents even in optical microscope (See in the center of the valve in Fig.76 View FIGURES 66–76 ).

There are no previous SEM studies in the Moroccan populations of P. atlasi . The main character of P. atlasi , is the presence of spines growing up from circular pits (Lange Bertalot et al. 2003) as well as in the specimens of Sardinia. The populations of P. infirma were found in Ouiouane ( Morocco) and in Radika Pond (North Macedonia). Pinnularia infirma ( Figs 32–46 View FIGURES 32–46 , 70–75 View FIGURES 66–76 ) is characterized by its narrow central area and its less panduriform and smaller size when compared with P. atlasi , P. cf. atlasi and P. baetica . The valve is characterized by: length 25.2–43.2 μm, width 5.2–7.2 μm and 11–13 striae in 10 μm (this study).