Climacosphenia elegantissima Lobban & Ashworth, 2022
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publication ID |
https://dx.doi.org/10.3897/phytokeys.208.89913 |
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persistent identifier |
https://treatment.plazi.org/id/68B61697-4DD9-56C5-9D7D-9AEC4B97CB5B |
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treatment provided by |
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scientific name |
Climacosphenia elegantissima Lobban & Ashworth |
| status |
sp. nov. |
Climacosphenia elegantissima Lobban & Ashworth sp. nov.
Figs 26 View Figure 26 , 27 View Figure 27 , 28 View Figure 28
References.
? Hustedt 1914 in Schmidt et al. 1874-1959, pl. 308, figs 5-10;? Hustedt 1931-1959, fig. 626; Navarro and Lobban 2009, p. 136, figs 64, 65 (all as C. elongata Bailey).
Diagnosis.
Differing from C. elongata in the greater length, especially in the stem, and narrower, linear apical portion, and from C. truncata Hustedt ex Simonsen in the shape of the wide part of the valve.
Description.
Cells attached in small groups to stout, branched mucilage stalks (Fig. 26A, E View Figure 26 ), at least 110 µm wide at the base and up to 2 mm long. Frustule generally deeper than wide, especially where stem first narrows below the apical pole, ratio there about 15 µm deep to 5 µm wide (Fig. 27A View Figure 27 ). Nucleus situated between two more-widely spaced craticular bars about 120 µm from apical pole (Fig. 26A, D View Figure 26 ); plastids lenticular. Valves 750-1305 µm long, linear toward apical pole, 22-24 µm wide, then tapering to a long linear stem, 5 µm wide, expanding to 10 µm at the pole (Figs 26A-C View Figure 26 , 27A View Figure 27 ). Stria density 27-28 in 10 µm through most of the valve but 18-21 in 10 µm near basal pole, sparser and more scattered inside annulus near basal pole (Fig. 27D, E, G View Figure 27 ). There was a crescent of scattered areolae at top of mantle at apical pole (Figs 27D, G View Figure 27 , 28A View Figure 28 ) (noticed in Climacosphenia spp. by Round 1982: figs 15, 16, 25). Annulus apparently open at basal pole, sides ± parallel in the wide area, 8.3 µm apart, in the stem 2.3 µm apart, expanded to 5 µm at the basal pole (Fig. 27C-G View Figure 27 ). Two or more stout spines on external apical pole (Figs 27D View Figure 27 , 28A View Figure 28 ), shallow transapical costae throughout except near basal pole (Fig. 27F, G View Figure 27 ). Pseudoseptum absent (Fig. 27F, G View Figure 27 ). Two girdle bands (Fig. 28A View Figure 28 ): valvocopula (Figs 26B, F View Figure 26 , 27B, C, F, I View Figure 27 , 28A-C View Figure 28 ) with fimbriate inner edge (Fig. 28B View Figure 28 ), stria density 19 in 10 µm (Fig. 28A, B View Figure 28 ) but increasing around foot pole, where there was also a row of pores on pars interior (Fig. 27I View Figure 27 ). Craticular bars widely spaced in wide part of the cell, with widest space corresponding to the location of the nucleus (Figs 26B View Figure 26 , 27B View Figure 27 ); in the stem becoming much closer together (Figs 26B View Figure 26 , 28C View Figure 28 ), often paired with the two bars apparently growing from opposite sides (Fig. 28C View Figure 28 ). In one specimen from culture, we observed porous bands of silica around several craticular bars near the apical pole (Fig. 28D View Figure 28 ). Copula fimbriate, more densely striated than the valvocopula but less than the valve, 22 in 10 µm (Fig. 28A, E View Figure 28 ). A search of abundant girdle views in whole mounts showed no sign of a pleura.
Holotype
(designated here). Specimen at 16.1 mm E, 12.8 mm S of the mark on slide 1861; deposited at Academy of Natural Sciences, Drexel University, Philadelphia, accession number ANSP GC20108. Fig. 27B View Figure 27 .
Registration.
Phycobank http://phycobank.org/103246.
Type locality.
Guam: Apra Harbor, Scuba Beach, 13.464°N, 144.656°E, epiphytic on filamentous red algae in farmer fish territory, collection number GU52U-2, 10 May 2015. C.S. Lobban and M. Schefter leg.
Additional materials examined.
GU44AI-5! (culture), GU44BM-7!, GU52G-B!, GU52X-1!, GU52Y-3B!, GU52AI-1!.
Etymology.
Superlative of elegans, with reference to the slender appearance of the extremely long cells.
Taxonomic comments.
The width of the apical pole and especially the distance between the annular lines are narrower than in C. elongata (Table 5 View Table 5 ) and the stem is also narrower, though the basal pole is inflated and slightly wider than C. elongata . Hustedt’s (1914) drawings of C. elongata have the greatly extended stems that are present in our new species, but the apical portions of his cells are generally elliptical rather than linear. However, the valvocopula ( Hustedt 1914, pl. 308, fig. 6) is notable in having parallel sides as far as the large space (i.e., where the nucleus would have been), so it is possible they represent C. elegantissima . Climacosphenia truncata from Borneo is also illustrated there (pl. 308, figs 1-4); it also has a very long stem but possesses an essentially triangular blade with a bluntly rounded apical pole. C. elegantissima is common as an epiphyte on filamentous seaweeds in Guam farmer fish territories and such habitats around the western Pacific/ IndoPacific may yield new material of C. truncata and other Climacosphenia spp.
Round (1982) showed porous bands of silica on craticular bars near the basal pole of both species only found in Hawaiian material. We saw them only once on apical bars in C. elegantissima . Their distribution and function are unknown.
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.