Luticola orientalis M.Rybak, Peszek, JP.Zhang & Witkowski, 2021

Rybak, Mateusz, Witkowski, Andrzej, Peszek, Lukasz, Kociolek, John P., Risjani, Yenny, Nguyen, Duc Hung, Zhang, Jinpeng, Yunianta,, Nguyen, Van Duy, Gastineau, Romain, Duong, Thi Thuy, Rosa, Philippe & Meleder, Vona, 2021, Marine and brackish Luticola D. G. Mann (Bacillariophyta) species from the Java Sea and South China Sea coasts with the description of three new species, PhytoKeys 183, pp. 115-142 : 115

publication ID

https://dx.doi.org/10.3897/phytokeys.183.71049

persistent identifier

https://treatment.plazi.org/id/2BFAB715-BE63-5579-8515-C71BF5813762

treatment provided by

PhytoKeys by Pensoft

scientific name

Luticola orientalis M.Rybak, Peszek, JP.Zhang & Witkowski
status

sp. nov.

Luticola orientalis M.Rybak, Peszek, JP.Zhang & Witkowski sp. nov.

Figures 2A -AH, 3 View Figure 2

Description LM.

Valves rhombic-lanceolate to rhombic in smaller specimens with narrowly rounded apices. Valves 9.5-22.1 μm in length, 5.4-8.5 μm in width (n = 30). Raphe filiform, axial area narrow and linear expanding into rectangular, narrow central area, stigma side of the central area bordered by 2-3 areolae, on side opposite stigma bordered by 1-2 areolae. Stigma located close to valve margin. Transapical striae easily distinguishable with LM, radiate throughout, 18-22 in 10 μm.

Description SEM.

Valve surface flat, the transition between valve face and the mantle abrupt marked with a stripe of hyaline silica. Axial area narrow becoming broader toward the valve middle, expanding into the rectangular central area. Externally raphe filiform and straight, distally strongly hooked in the same direction on valve apices, proximal raphe endings close to each other, simple and clearly bent towards the primary valve side (opposite the stigma). Valve mantle with a single row of elliptical areolae. Internally raphe branches straight, with proximal ends simple and relatively distant, terminating at the apices as small, indistinct helictoglossae. Transapical striae composed of 4-6 rounded or slightly transapically elongated areolae, often becoming smaller close to valve margin, internally occluded by hymenes. Areola occlusions positioned at the internal valve surface. Externally elongated stigma positioned close to valve margin of the valve secondary side. Internal stigma opening with large-lipped structure. Internally longitudinal channel visible on face and mantle conjunction, with relatively large silica flap on site opposite to stigma opening. Longitudinal channel covered by hymen similar to those occluding areola.

Holotype.

Slide SZCZ27007 stored in A. Witkowski Diatom Collection of the Institute of Marine and Environmental Sciences, University of Szczecin, holotype specimen is Fig. 2O View Figure 2 .

Isotype.

Slide no. 2018/425 and unmounted material with the same number at the University of Rzeszów, Poland.

Type locality.

Indonesia. Java Island: Pantai Bentar in Probolinggo at North coast, a periphyton from a boulder, 07°46'41"S, 113°16'34"E, leg. Y. Risjani, Yunianta and A. Witkowski 1st March 2020.

Etymology.

The name refers to the geographical location - east (lat. Luticola orientalis - eastern).

Distribution.

Abundant in holotype sample SZCZ27007, and in periphyton from the plastic pier at Pantai Bentar in Probolinggo, and was also present in sample SZCZ27006 very close to the holotype habitat. The new species was also observed in an epilithic sample from Fenjiezhou Island at the coast of Hainan Island, NW South China Sea in sample SZCZ27176, and from the Xuân Thúy Mangrove in NE Vietnam where it was found in the biofilm from wild oysters, sample SZCZ26472.

Taxonomic comment.

Valve shape of Luticola orientalis sp. nov. is similar to Luticola cribriareolata sp. nov., however, the former species can be distinguished by stria density, which are finer than in L. cribriareolata sp. nov. Luticola orientalis sp. nov. is also similar in terms of valve outline to L. nosybeana and L. madagascarensis from Nosy Be Island, however, the former species has simple proximal raphe endings without any grooves (Table 2 View Table 2 ) which are distinct in both Madagascar species ( Bąk et al. 2019).