Lindavia biswashanti Mohan & Stone, 2018

Mohan, Joseph, Stone, Jeffery R., Nicholson, Kirsten, Neumann, Klaus, Dowling, Carolyn & Sharma, Subodh, 2018, Lindavia biswashanti, a new diatom species (Bacillariophyta) from Gokyo Cho, Himalayan Range, Nepal, Phytotaxa 364 (1), pp. 101-107 : 102

Lindavia biswashanti Mohan & Stone spec. nov. ( Figs 2 , 3 )

Valves are discoid, 4–13 μm in diameter. Valve face is separated into a hyaline central area and a marginal area marked by radial striae. The central area exhibits radial undulation; three alternating depressed wedges are bounded by three raised wedges. Central area comprises 2/3 of the valve face area ( Fig. 2 ). Doubly punctate fascicles are distributed 13– 20 in 10 μm. Internally the fascicles perforate into alveolar chambers with a single round opening.A single fultoportula is present on the valve face near the center of the valve. Three to five mantle fultoportulae are evenly distributed around the margin. Externally the valve face and mantle fultoportulae are simple round perforations. Internally both types of fultoportulae consist of a central pore with circular raised sides. On opposite sides of the central pore exist two crescent-shaped satellite pores both with raised edges ( Figs. 3 , E & F). Internally the mantle fultoportulae reside on costae ( Figs 3 , D & F). A simple, slightly raised rimoportula is exhibited internally ( Figs. 3 , D & F). Externally the rimoportula is inconspicuous ( Figs. 3 , A & B).

Type: — NEPAL. Province No. 1 (Solukhumbu District): Sagarmatha National Park, Gokyo Cho, 4750 m, N 27.953863, E 86.692920, collected by K. Nicholson on 02 May 2016, General Collection no. 36357 ANSP! (Holotype, Fig 2 , C is the encircled holotype specimen)

Etymology: —The lake from which Lindavia biswashanti has been recovered is considered to be sacred by Buddhists and Hindus. As such, L. biswashanti is named in respect for the Tengboche monks; biswashanti means ‘world peace’ in the Nepali language and is their message to the world.

Remarks:— Lindavia biswashanti differs from Pantocsekiella hispanica (K.T. Kiss, E. Hegewald et Ács) K.T. Kiss et Ács (2016: 66) by lacking round nodes on the undulations on the central area. P. hispanica exhibits three areolae per fascicle whereas L. biswashanti has two per fascicle. P. hispanica also exhibits greater numbers of mantel fultoportulae than L. biswashanti ( Table 1). Pantocsekiella ocellata (Pantocsek) K.T. Kiss et Ács (2016: 62) differs most notably by exhibiting papillae and orbiculi depressi in the central area. L. biswashanti lacks these distinct features. P. ocellata also show greater numbers of areolae per fascicle and greater number of mantel fultoportulae ( Table 1). Pantoscekiella tripartita (Håkansson) K.T. Kiss et Ács (2016: 69) differs from L. biswashanti by having additional protrusions in the central area and exhibiting spinules on the interfascicles marking the interface of the valve face and mantel ( Håkansson, 2002). L. biswashanti differs from L. antiqua var. minor by having hyaline undulations in the central area whereas L. antiqua var. minor is described as having delicately punctate depressions in the central area. Therefore, we suggest that the specimen identified by Misra et al. (2009) Plate 1, Fig. 1 is L. bishwashanti not L. antiqua var. minor because it lacks punctate depressions.

Figures

FIGURE 1: Map of the Sagarmatha National Park region, Province No. 1, Solukhumbu District, Nepal. The region is dominated by some of the tallest peaks in the world. Mount Everest (8,848 m) and Cho Oyu (8,188 m) are shown. The lakes from which samples were collected comprise some of the highest elevation lakes in the world. Gokyo Cho is the locality from which the holotype material is collected. Location of the region in the Himalayas (inset).

FIGURE 2: Size diminution series of Lindavia biswashanti. Light microscope images captured under a Leica DM2500. The holotype specimen is image C. Scale bars are all 10 μm. The central fultoportula is readily visible in larger specimens (A–F) and slightly offset from the center of the valve. Rimoportulae are indistinct in light microscope. The distinguishing features are the three triangular-shaped raised areas juxtaposed with three lowered areas to make six sectors in a superficial likeness of the nuclear fallout-shelter symbol.

FIGURE 3: Scanning electron micrographs of Lindavia biswashanti. Image A exhibits the external view with central fultoportula (cfp), rimoportula (rp), and marginal fultoportulae of which one is arrowed (mfp). Image B is a small specimen that exhibits granules around the margin. Interior expressions of the central fultoportula, rimoportula, and marginal fultoportula are shown in images D & E. Image F is a close up of the rimoportula and marginal fultoportula shown in image D.