Gomphonema rajaguruii sp. nov., a new diatom (Bacillariophyceae) species from the Western Ghats, India Author Yogeshwaran, Murugesan 0000-0002-8915-5230 Biodiversity & Palaeobiology Group, Agharkar Research Institute, Pune 411004 India yogeshwaranm@aripune.org Author Kociolek, John Patrick 0000-0001-9824-7164 Museum of Natural History and Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309, USA patrick.kociolek@colorado.edu Author Karthick, Balasubramanian 0000-0003-4066-2458 Biodiversity & Palaeobiology Group, Agharkar Research Institute, Pune 411004 India karthickbala@aripune.org text Phytotaxa 2023 2023-05-05 595 2 199 208 http://dx.doi.org/10.11646/phytotaxa.595.2.6 journal article 304819 10.11646/phytotaxa.595.2.6 575866e8-bfc6-49c5-aa59-9206f501787e 1179-3163 7905892

TABLE 1. Comparison between the morphologically similar species and Gomphonema rajaguruii sp. nov. from the different sources. (— indicates unknown)

Features / Species	Gomphonema rajaguruii sp. nov	Gomphonema kallarense Pardhi et al. 2020	Gomphonema lujanense E. Reichardt & Maidana 2008	Gomphonema pseudointermedium E. Reichardt 2008	Gomphonema zellense E. Reichardt 1999	Gomphonema supertergestinum E. Reichardt 2009	Gomphonema irroratum Hustedt 1945
Valve length (μm)	45.5–71.0	32.9–46.6	176.4–52.6	28.0–55.0	27.0–60.0	22.0–52.0	24.0–37.0
Valve width (μm)	8.8–12.8	6.8–9.1	5.6–9.0	6.6–7.7	9.2–11.0	7.0–9.0	5.5–7.5
Valve shape	Lanceolate - Rhombic	Lanceolate-clavate	Lanceolate-clavate	Clavate	Clavate	Lanceolate to elliptic	Clavate
Head pole	Slightly broadly rounded towards pole	Broadly rounded, almost flat, slight capitate	Bluntly rounded or truncate with small pore field	Obtusely rounded	Rounded	Broadly rounded	Broadly rounded
Foot pole	Narrowly rounded, elongated towards pole	Narrow rounded	Narrow rounded	Narrow rounded	Rounded	Narrowly rounded	Rounded
Striae (10 μm)	9–10 in central area 10–12 towards poles	9–13	7–12	10–11	8–10	9–12	14–16
Striae pattern (Head to Centre)	Slightly radiate from head pole to central valve	Slight radiate	Moderately radiate	Strongly radiate	Radiate	Radiate	Strongly Radiate
Striae pattern (Centre to Foot)	Strongly radiate towards the foot pole	Radiate	Radiate	Weakly radiate	Slightly radiate	Parallel	Radiate
Areolae (10 μm)	60–70	60–70	—	—	22–26	—	30–35
Areolae pattern	Biseriate, slit-shaped, aligned alternatively	Biseriate, slit-shaped, aligned alternatively	Biseriate, slit-shaped, aligned alternatively	Mostly biseriate, slit-shaped	Uniseriate and Partially biseriate	Biseriate, Round	Biseriate, round
Raphe	Weakly undulate	Lateral to undulate	Lateral	Lateral fissure somewhat undulate	Narrow, Lateral	Lateral or filiform	Lateral, undulated
Axial area (size)	Slightly broader, linear to lanceolate	Broad to narrow, lanceolate	Moderately narrow, linear to lanceolate	Narrow, linear	Narrow, linear	Narrow, linear	Narrow, linear to lanceolate
Central area	Distinct, small	Distinct, small	Unilaterally widened with one greatly shortened stria	Small	Large to nearly rectangular	Distinct, Extended to the edge, Very short striae	Small, irregular to elliptic
Pseudoseptum	Present	Present	—	—	Absent	Present	—
Stigma Externally	Oval	Round	Round	Round	Round	Round	1
Habitat	Wet wall	Stream	River	Lake	Lake	Lake	Lake
Type locality	Mahabaleshwar, Maharashtra, India	Kallar stream, Kerala, India	Lujan river, Argentina	Inley Lake, Burma	Zellsee Lake, Germany	Brandenburg, Germany	Balkan Highlands, Balkan Peninsula
Reference	Present study	Pardhi et al. (2020)	Reichardt (2008)	Reichardt (2008)	Reichardt (1999)	Reichardt (2009)	Hustedt (1945)