Gomphonemopsis gaoi Lang Li, Changping Chen & Junxiang Lai, 2024

Li, Lang, Nong, Qun-Zhuan, Chen, Chang-Ping, Li, Yu-Hang & Lai, Jun-Xiang, 2024, Two new diatom species of the genus Gomphonemopsis (Bacillariophyceae) from the coast of China and two new combinations for the genus, PhytoKeys 239, pp. 255-266 : 255

Gomphonemopsis gaoi Lang Li, Changping Chen & Junxiang Lai sp. nov.

Fig. 2A-P

Gomphonemopsis exigua - Gomphonemopsis aff. G. exigua in Lange and Tiffany 2002, p. 198, fig. 74.

Type materials.

Holotype. Slide SZIII161114 deposited in Biology Department Herbarium, Xiamen University (AU), Xiamen, China.

Iconotype. Fig. 2J .

Type locality.

No. 3 fishing pond, Futian Mangrove Nature Reserve, the South China Sea (22°31'28.11"N, 114°0'41.37"E). Separated from the exoskeleton of marine copepods by Lang Li, 14 November 2016.

Description.

LM (Fig. 2A-I ). Valves narrowly lanceolate, isopolar with acutely rounded apices, 28.5-30.5 μm long, 4.0-5.0 μm wide. Primary and secondary sides can be easily distinguished because of the obvious interruptions in the stria pattern, which are termed "Voigt faults" (Fig. 2A , black arrowheads). Axial area linear and very narrow, widening towards valve centre. Central area small, sometimes slightly wider on the primary side than the secondary side. Raphe straight with distant simple proximal endings. Striae uniseriate, parallel in the middle and slightly radiate near apices, 24-26 in 10 μm.

SEM (Fig. 2J-P ). Valve face flat, with a clear transition to mantle (Fig. 2J ). Each of striae comprised of one narrow, elongated areola on valve face and one oblong areola on the mantle (Fig. 2J-L ). Valve mantle relatively shallow, with 10-14 radiated slits at apices (Fig. 2K, L ). Axial area distinct, forming a narrow, lanceolate hyaline zone and becoming wider in the central area (Fig. 2J ). Central area transversely expanded, surrounded by irregularly shortened striae (Fig. 2L ). Raphe filiform, composed of two coaxial branches of equal length (Fig. 2J ). Both proximal and distal endings almost straight, not enlarged (Fig. 2K, L ). Internally, proximal raphe endings small, slightly deflected towards the primary valve side (Fig. 2M, O ), whereas distal endings terminate as weakly developed helictoglossae (Fig. 2N ). Valvocopula open, possessing two parallel rows of subcircular poroids (Fig. 2P ).

Etymology.

The epithet honours Prof. Yahui Gao (Xiamen University, China), in recognition of his contributions to marine diatom taxonomy research in China.

Distribution and ecology.

In addition to the type locality, Gomphonemopsis gaoi may also be distributed in the Salton Sea of the United States ( Lange and Tiffany 2002: fig. 74). This taxon is an epizoic diatom on marine copepods. Water temperature of the sampling site was 27.7 °C, and salinity was 12 psu.

PhycoBank registration.

http://phycobank.org/104209.

Figures

Figure 2. Gomphonemopsis gaoi A-I light micrographs (I phase contrast), note the Voigt faults on the secondary side (black arrowheads) J-P scanning electron micrographs J external view of an entire valve, iconotype specimen K external detail of the apex, showing the slit-like pores L external detail of the central area M internal view of an entire valve N internal detail of the apex, showing the slit-like pores O internal detail of the central area P valvocopula with two rows of subcircular poroids. Scale bars: 10 μm (A-I); 5 μm (J, M); 1 μm (K, L, N-P).