Serratifera sp. 1

Li, Chun L., Witkowski, Andrzej, Ashworth, Matt P., Dąbek, Przemysław, Sato, Shinya, Zgłobicka, Izabela, Witak, Malgorzata, Khim, Jong Seong & Kwon, Chun-Jung, 2018, The morphology and molecular phylogenetics of some marine diatom taxa within the Fragilariaceae, including twenty undescribed species and their relationship to Nanofrustulum, Opephora and Pseudostaurosira, Phytotaxa 355 (1), pp. 448-450 : 448-450

Serratifera sp. 1 CCMP3169 (SEM: Figs 455–458 )

Valves oval with linear sternum ( Figs 455–456 ). Length: 2.0–2.5 µm, width: 2.0–2.5 µm and estimated stria density: 30–33 /10µm (n = 8). Striae uniseriate, each composed of one (sometimes two) areolae on both valve face and mantle ( Figs 455–457 ). Areolae transapically-elongate, occluded by complex volae, with multiple rods originating from transapical sides of areolae ( Figs 455–456 ). Marginal spines columnar and positioned within striae ( Fig. 458 ). Both apical pore fields composed by one round pore ( Fig. 457 ). Segmented and scale-like copulae observed ( Fig. 458 ). Rimoportulae absent ( Fig. 456 ).

Distribution: This clone was obtained from the NCMA collection and sampled from Palmyra Atoll, Line Islands, Polynesia, North Pacific.

Observations: Originally labeled as “ Staurosira complex” at NCMA, we feel the valve morphology identifies this strain as Serratifera , based on the striae consisting of one (sometimes two) areolae on both valve face and mantle, a distinctly narrow-linear sternum, and the DNA data support this hypothesis. Clone CCMP3169 has many similarities with oval cells of S. sourniae , and overlapping size dimensions. Without a defining character to identify this clone, we are hesitant to formally describe it.

S erratifera sp. 2 SZCZP526 (LM: Figs 177–178 , SEM: Figs 459–464 )

Valves elliptical. Sternum narrow-linear. Striae alternate ( Figs 177–178 ). Length: 2.5–4.5 µm, width: 2.0–2.5 µm and estimated stria density: 20–24 /10µm (n = 10). Striae uniseriate, each composed of single (sometimes two) areola on both valve face and mantle ( Figs 459–461 ). Areolae transapically-elongate, occluded by branched volae, with multiple rods projecting from transapical sides (sometimes apical sides) of areolae ( Fig. 460 ). Apical pore fields reduced ( Figs 460–461 ). Marginal spines with spatulate tips and swollen base, positioned in row of striae ( Fig. 463 ). Several plain copulae present in girdle assembly and fringed structure at margin of copula detected ( Fig. 464 ). No rimoportulae ( Fig. 462 ).

Distribution: Nha Trang Cam Ranh Bay, the Vietnamese coast of the South China Sea, 12°19'48.0"N 109°12'36.0"E.

Observations: This species possesses the morphological characteristics of Serratifera , but without morphological characters to distinguish it from other species, as suggested by its solitary phylogenetic position revealed by DNA sequence data, we do not formally describe it at this time.

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Stauroforma rinceana Meleder, Witkowski & Chunlian Li , sp. nov. (LM: Figs 38 , 179–183 , SEM: Figs 465–471 )

Chloroplast one, compressed to one valve face ( Fig. 38 ). Frustule rectangular in girdle view, aggregated together without any pattern ( Fig. 38 ). Valves heteropolar, clavate in larger cells and almost isopolar and ovate in smaller cells ( Figs 179–183 ). Sternum indistinct. Length: 4.5–11.5 µm, width: 2.0–3.5 µm and stria density: 21–24 /10 µm (n = 10).

Striae uniseriate, opposing, becoming slightly radiate near apices, extending from valve face to mantle continuously ( Figs 465–467 ). Areolae small, slit-like, occluded by branched volae, with one rod projecting from apical sides of areolae and parallel to transapical-axis ( Fig. 467 ). Short striae observed near foot pole, creating a hyaline area ( Figs 465, 467 ); APFs at head pole relatively large, positioned on valve face, composed of irregular small pores ( Figs 465–469 ). APFs at foot pole small, located on mantle, and consisted of much smaller pores, which regularly distributed in rows ( Fig. 470 ). Copula plain, no complete cingulum observed ( Fig. 471 ). No rimoportulae ( Fig. 468 ).

Etymology: This species is dedicated to the professor Ives Rince, a French distinguished specialist on marine diatoms, PhD supervisor of V.M.

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Holotype: BM 101911 , in the Natural History Museum , London, UK, collected by V. Méléder, September 2010.

Isotype: Slide SZCZCH1603 , deposited in Palaeoceanology Unit , Faculty of Geosciences, University of Szczecin .

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Type habitat: Atlantique, Baie de Bourgneuf, Lyarne, France.

Observations: Under LM, this species looks similar to Stauroforma atomus (Hust.) Talgatti, Wetzel, Morales & Torganin (2014: 45, figs 1–50) and small specimens of Stauroforma schulzii (Brockmann) Gogorev in Gogorev & Lange (2014: 45). But it can be distinguished from these by stria density (in S. atomus , the stria density is 25–30 / 10 µm and in S. schulzii , the stria density is 13–16 /10 µm). Furthermore, under SEM, this species differs from the aforementioned taxa by short striae near the foot pole. Additionally, the pattern of the areolae occlusions are different; in S. atomus ; they are usually two simple opposing volae parallel to the transapical-axis, originating from apical sides of the areolae and meeting each other at the centre of the areola. In Stauroforma rinceana , however, there is only one branched vola, originating from one apical side of the areolae and parallel to the transapical-axis. The newly described species also differs from Fragilaria gedanensis Witkowski (1993: 62 , figs 3l–q), which has similar valve outline and striation pattern, but F. gedanensis has much coarser striae (9–14 in 10 µm) and the striae are biseriate ( Witkowski & Lange-Bertalot 1993).

Figures

FIGURES 455–458. Scanning electron micrographs of Serratifera sp.1 (clone CCMP 3169). Fig. 455. External view, showing narrowly-linear sternum and each stria consisting of a single transapically-elongated areola (sometimes two smaller areolae) on both valve face and mantle. Fig. 456. Internal view, showing the absence of rimoportulae. Fig. 457. Tilted valve, showing one row of areolae on mantle. Fig. 458. Girdle view, showing segmented (indicated by arrow) copulae.

FIGURES 130–183. Light micrographs, showing morphology of cleaned valves. Figs 130–137. Serratifera sp. (S. cf. andersonii), showing morphological variations within different populations. Figs 138–142. Serratifera brevis. Figs 143–147. Serratifera clavata. Figs 148–151. Serratifera corallina. Figs 152–156. Serratifera namibica. Figs 157–160. Serratifera nosybeana. Figs 161–165. Serratifera parkii. Figs 166–168. Serratifera punctata. Figs 169–171. Serratifera rhombica. Figs 172–175. Serratifera sourniae. Fig. 176. Serratifera takanoi. Figs 177–178. Serratifera sp. 2. Figs 179–183. Stauroforma rinceana. Figs 130–131. Clone SZCZM910, from Lokrum, Croatia. Figs 132–134. Clone SZCZP693, from Sea of Marmara, Turkey. Figs 135–137. Clone SZCZP696, from San Sebastian Beach, Canary Islands. Scale bar, 10 µm.

FIGURES 459–464. Scanning electron micrographs of Serratifera sp. 2 (clone SZCZP526). Figs 459–461. External views, showing narrowly-linear sternum and each stria composed of a single transapically-elongate areola (sometimes two) on both valve face and mantle. Fig. 462. Internal view, showing the absence of rimoportulae. Fig. 463. Girdle view, showing spatulate marginal spines associated with swelling base (indicated by arrowhead). Fig. 464. Girdle view, showing plain and open copulae, and fringed structure (indicated by arrowhead) observed at the margin of copula.

FIGURES 33–38. Light micrographs, showing colonies and chloroplast information of living diatoms. Fig. 33. Serratifera parkii. Fig. 34. Serratifera punctata. Fig. 35. Serratifera rhombica. Fig. 36. Serratifera sourniae. Fig. 37. Serratifera takanoi. Fig. 38. Stauroforma rinceana. Scale bar in Fig. 35, 20 µm; all other scale bars, 10 µm.

FIGURES 465–471. Scanning electron micrographs of Stauroforma rinceana (culture SZCZCH1603). Figs 465–466. External views, showing clavate valve with striae consisting of several slit-like areolae extending from valve face to mantle continuously, and short striae (indicated by arrows) near foot pole APFs. Fig. 467. A smaller external view, showing elliptical valve with short striae (indicated by white arrows) near foot APFs and branched volae (indicated by black arrow) projecting from apical side of areolae. Fig. 468. Internal view, showing the absence of rimoportulae. Fig. 469. Close up of a valve, showing head APFs composed by radiate pores from the end of sternum to mantle. Fig. 470. Close up of a valve, showing hyaline area near the apex and foot apical pore field with five observed vertical rows of pores located on valve mantle. Fig. 471. Plain copulae.