Pinnularia hustedtii F. Meister 1935: 102

Williams, David M., Liu, Bing & Taxböck, Lukas, 2022, Pinnularia hustedtii (Bacillariophyta): Notes on specimens from Wuling Mountains, China and from type material, Phytotaxa 536 (3), pp. 294-300 : 294-298

Pinnularia hustedtii F. Meister 1935: 102 , taf. 9, fig. 82 ( Fig. 1 )

Synonym:— Pinnularia pseudotabellaria H.Kobayasi in H.Kobayasi & Kaz.Ando 1977: 248, pl. 8, figs 60, 61 ( Fig. 5 )

Type: — CHINA,=Pearl River, “Selten im Cantonfluss” [rarely in Canton River, China], Z + ZT! 2 Meister 3312065 ( Fig. 7 , slide lost, holotype = Meister 1935: taf. 9, fig. 82), isotype = Z + ZT! Meister 3312040! ( Fig. 8 , specimen in Figs 2, 3, 4, 6 ).

Original description:“ — Schalen linear mit angeschwollener Mitte und kopfigen Polen, 232 μ lang, 21 μ breit. Querrippen 11 in 10 μ, in der Mitte radial, gegen die Enden konvergent, von einem breiten Längsband gekreuzt. Raphe komplex, Zentralporen einseitig abgebogen. Axialarea ziemlich schmal, in der Mitte elliptisch erweitert” ( Meister 1935: 102).

In Meister’s diatom collection in Z + ZT there are six pages in his notebooks that deals with specimens obtained from Pearl River (Canton River), China (“Cantonfluss in Südchina”, slides 331240-331273; further commentary on Meister’s Asian collection of diatoms can be found in Riaux-Gobin et al. 2015, 2017). As Meister notes in his paper, “Von Herrn Manfred Voigt, Ingenieur, in Shanghai erhielt ich einige Proben von Kieselalgen aus Ostasien […]” ( Meister 1935: 87), and later “Herrn Manfred Voigt, Elektroingenieur in Shanghai, verdanke ich die Zusendung einiger mariner Diatomaceenmaterialien aus den Jahren 1933 und 1934. Das eine stammt aus dem Cantonfluss in Südchina, ein anderes von Kiang-Wan, China ” ( Meister 1935: 96). Only the slides from “Cantonfluss” with Meister’s notes suggesting new species in his notebooks and those described in Meister (1935) are listed in Table 1 .

On the fifth page of the notebook for slide 3312065, the name ‘ Pinnula [aria]’ is recorded suggesting this may be the specimen of Pinnularia hustedtii . The inclusion of slide co-ordinates would also suggest this is, or was, the holotype specimen ( Fig. 7 ). All the “Cantonfluss” slides have been found in Meister’s collection with the exception of 3312065! - unfortunately raw material for this slide (no. 2439) is also lacking. Inspection of the other “Cantonfluss” slides, 3312040 to 331273, yielded just one broken valve of a species of Pinnularia on slide 3312040, which can be interpreted as Pinnularia hustedtii ( Figs 2–4, 6 ). Thus, the specimen used for the illustration of Pinnularia hustedtii in Meister (1935, p. 102, taf. 9, fig. 82) should be regarded as a lost type specimen rendering the illustration ( Meister 1935, taf. 9, fig. 82, our Fig.1 ) the holotype and the specimen found on slide 331240 an isotype ( Figs 2–4, 6 ).

1 The slide number means the following: 33 refers to the year [1933]; 12 probably refers to the month [December]; 040, etc. is the running number for the series.

Early in his diatom studies, Voigt engaged in a long and detailed correspondence with Robert Ross at the Natural History Museum (preserved in the NHM diatom collection), dating from Ross’s appointment as diatomist in 1936 ( Cox et al. 2006). Although Voigt sent Ross material from various places in Asia, none of the “Cantonfluss” was among them so it is not possible to select a neotype for Pinnularia hustedtii from any items at BM.

The terminology largely follows Ross et al. (1979) and Liu et al. (2018).

Description of the Wuling Mountains Specimens (LM, Figs 9–14 , SEM, Figs 15–24 ):— Valves linear with parallel margins, gently expanded at valve centre, broad, rounded ends that slightly expand, marginally less so than at centre ( Figs 9–16 ). Central area small, asymmetric, expanded on primary valve side ( Figs 9–16, 19 , 20 ). Sternum linear, broadening at the centre, tapering at poles, less than ⅓ breadth of valve, with conspicuous central area unilaterally expanded ( Figs 9–16 ). Striae crossed by distinct longitudinal band, about ⅓ length of striae ( Figs 9–16 ). Valve dimensions: length 208–264 μm, width at centre, 15.9–22.6 μm, along parallel valve length 14.4–18.1 μm, at slightly expanded pole 18.3–20.8 μm; striae 11–12 in 10 μm, parallel along valve length, converging at poles. External proximal raphe endings slightly expanded and unilaterally deflected ( Figs 21, 22 ). Distal raphe fissures clearly hook-shaped ( Figs 21, 22 ), continuing onto mantle ( Figs 21, 22 ). Internal raphe straight ( Figs16–19 ). Distal raphe endings terminating with distinct helictoglossa ( Figs 17, 18 ). Striae composed of large alveolus ( Figs 17–19 , 24 ), each composed of ca. 6 rows of small areolae ( Fig. 24 ). Girdle simple, valvocopula plus 1 (?) further copula ( Fig. 15 ).

Comments:— There are few records of Pinnularia hustedtii . After Meister, Skvortzov recorded it from Lake Kizaki, Nagano, Japan (Skvortzov 1936, p. 43, pl. 8, fig. 5) and subsequently described the new variety Pinnularia hustedtii var. nipponica Skvortzov also from Japan, differing “from the type in its more robust striae and broader valves” (Skvortzov 1937: 205, pl. 2, fig. 6, “Ikeda Lake”, Kyűshű island, Japan 3). Hirano added another variety, Pinnularia hustedtii var. rangtangense Hirano (1969: 20 , pl. 5, fig. 7, invalidly published as no type was provided), which he found in Nepal in “Mud bottom and attached substance in stream on the slope of Mt. Salbachiome [Salbachome]” ( Hirano 1969: 6).

Some have considered Pinnularia pseudotabellaria H.Kobayasi (first described from Japan by H.Kobayasi in H.Kobayasi & Kaz.Ando 1977: 248, pl. 8, figs 60, 61 = our Fig. 5 , “Nishida-numa”, Japan 4) to be a synonym of Pinnularia hustedtii (http://www.biwahaku.jp/research/data/atlas/pinhustedtii.htm)—but not everyone (cf., Lee et al. 2019: 161, Tuji & Mayama 2019: 40). Pinnularia pseudotabellaria seems not to have been recorded outside Japan ( Makita & Tanaka 2018: pl. 5, figs 1, 25), with the exception of Lee et al. (2019) who commented on specimens “from the source of Han and Nakdong Rivers” in South Korea, and suggested that P. pseudotabellaria differs from P. hustedtii such “that the ultra-structure of the raphe is filamentous” ( Lee et al. 2019: 161). We have retained P. pseudotabellaria as a synonym of P. hustedtii with the view that the specimens in Lee et al. (2019: figs 101–103) would repay further study.

The record for New Zealand in Harper et al. (2012: 151) was derived from Foged (1979: 95, by way of Cassie 1984: 88). Foged did not illustrate his specimens but they are still available for study ( Foged 1979: 95, “591a/1966 | Okataina lake” […] “Bottom sample […] 40m […] 209 taxa”, Foged 1979: 14).

Some notes on the name Pinnularia hustedtii :=The name Pinnularia hustedtii was used for a second time by Karl Mölder (1899–1975) for a very different species ( Mölder 1951: 27, pl. II, fig. 28, pl. III, fig. 1, “Säämäjärvi” [Lake Syamozero], Russia). As it is a junior homonym, a new name is required. Niels Foged (1906–1988, see Håkansson 1988) later added the forma spitsbergensis Foged (1981) , which also needs a new name. These changes are undertaken below:

Figures

FIGURES 1–8. 1. Pinnularia hustedtii F.Meister, reproduction of Meister 1935: 102, taf. 9, fig. 82. 2, 3, 4, 6. Specimens of Pinnularia hustedtii from ‘Z + ZT Meister 3312040’. Fig. 5 is a reproduction of Pinnularia pseudotabellaria H.Kobayasi in H.Kobayasi & Kaz.Ando 1977: 248, pl. 8, figs 60, 61. Fig. 7 is a reproduction of page from Meister’s notebook for ‘Z + ZT Meister 3312065, lost holotype. Fig. 8 is a reproduction of page from Meister’s notebook for ‘Z + ZT Meister 3312040’, isotype (specimen in Figs 2–6). Scale bars: 50 μm (Figs 2, 3), 10 μm (Figs 4, 6).

FIGURES 9–14. Pinnularia hustedtii F.Meister, light microscope (LM) images from Wuling Mountains material. Scale bar: 50 μm.

FIGURES 15–19. Pinnularia hustedtii F.Meister, scanning electron microscope (SEM) images from Wuling Mountains material. 15–16. Entire valves with girdle attached in Fig. 15. 17–19. Internal detail of striae, raphe, helictoglossae and central nodule. Scale bars: 10 μm (Fig. 15), 20 μm (Fig. 16), 5 μm (Figs 17–19).

FIGURES 20–24. 20. Internal view of central nodule of raphe. 21–23. External views of striae, raphe, raphe endings at centre. 24. Detail of internal striae. Scale bars: 2 μm (Figs 20–23), 1 μm (Fig. 24).