Plagiogramma subatomus Lobban, S.Konno, Y.Arai

Lobban, Christopher S., 2021, New species of benthic marine diatoms (Bacillariophyta) from the Western Pacific islands of Guam and Yap, Phytotaxa 508 (3), pp. 235-265 : 236-237

publication ID

https://doi.org/10.11646/phytotaxa.508.3.1

persistent identifier

https://treatment.plazi.org/id/35288784-6A2A-EC0A-8084-1683FF798021

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scientific name

Plagiogramma subatomus Lobban, S.Konno, Y.Arai
status

sp. nov.

Plagiogramma subatomus Lobban, S.Konno, Y.Arai & R.W. Jordan, sp. nov. Figs 1–6 View FIGURES 1–6

Diagnosis:— Differing from P. atomus in forming chainlike colonies with frustules linked by spines, smaller valves, and the space between the central bars almost completely covered over by silica, leaving only a small opening in the pseudoseptum.

Description:— Live cells not observed. Frustules joined face to face in chains by spines ( Figs 2. 3, 6 View FIGURES 1–6 ). Valves 9.0–12.5 µm long, 4.6–6.6 µm wide, strongly constricted at the center and with rostrate apices ( Figs 1–6 View FIGURES 1–6 ). Striae about 17 in 10 µm. The central pseudoseptum boxlike with only a small opening in the middle ( Figs 3, 4, 5 View FIGURES 1–6 ). Areolae closed by complex rotae; a series of slits on the mantle at each apex ( Figs 2, 3 View FIGURES 1–6 ). Three plain copulae ( Figs 4, 6 View FIGURES 1–6 ), one wide (probably the valvocopula) with the open end filled by a prominent ligule on the closed end of the middle band; the third band appeared narrow throughout, although still somewhat wider at the apices ( Fig. 6 View FIGURES 1–6 ).

Holotype hic designatus:— Specimen at 10.5 mm E, 12.2 mm S of mark on slide 495, deposited at ANSP, accession # ANSP-GC20099 . Fig. 1 View FIGURES 1–6 . Registration: http://phycobank.org/102753.

Type locality:— GUAM: Apra Harbor , GabGab reef, 13.443 N, 144.643 E., depth ca. 8 m, epiphytic on seaweeds in territory of farmer fish Plectroglyphidodon lacrymatus , sample GU44I-1. C. Lobban and M. Schefter, 29 Oct. 2007 GoogleMaps .

Etymology:— A reflection of its being even smaller than P. atomus .

Additional Records:— F.S.M. Yap: Ruul, Yinuuf-Minaeg, Y18E!, Nimpal MPA, Y36-4!. Chuuk: Moch Island at the Eastern Passage of the barrier reef, TK4!. PALAU. Jellyfish Lake ( Konno 2006), Mekeald reef, PW2009-31 ( Arai, 2010), both as P. bilobatum ; MARSHALL ISLANDS. Jaluit Atoll, J5!.

Comments:— In contrast to P. subatomus , the apical mantle of P. atomus has large cribrate areolae and there is a clearly defined apical pore field on the rostrate part of the valve face, comprising lines of closely spaced pores with parallel ridges of ornamentation; P. atomus has one spine at each apex and its cells join in zigzag colonies ( Sato et al. 2008; also seen in Guam record, Lobban 2015a, fig. 106). Its valves are 23.5–26.2 µm long with rostrate ends, widest dimension 10.6–11.7 µm, 10–12 striae in 10 µm, and the central pseudosepta are sturdy but not covered ( Sato et al. 2008). Plagiogramma constrictum (see Williams 1988, pl. 49, figs 6, 7; Hein et al. 2008, pl. 4, figs 11, 12) is both small and narrow, 10–19 µm long x 3 µm wide, but has a much less pronounced central constriction. Both of the taxa named as Plagiogramma bilobata P. bilobata Brun 1894: 86 , pl. 6, fig. 20) and P. bilobata Leuduger-Fortmorel 1898: 39 , pl. 8, fig. 4)—are still further from our material.

LICMOPHORALES F.E.Round emend E.J. Cox

Licmophoraceae Kützing

Licmophora C.A. Agardh 1827: 628

Licmophora in the Western Pacific has shown high species diversity, with many new species identified (Lobban 2013, Lobban & Schefter 2013, Lobban et al. 2011, 2015, 2018, Macatugal et al. 2019). We have shown that copula ultrastructure can provide useful taxonomic characters, as each mature epicingulum has five different elements ( Lobban et al. 2018), in addition to the valve ultrastructure first studied in detail by Honeywill (1998). I present here two further species that can be distinguished on valve characters alone, although I have provided copula information to the extent possible.

Agardh, C. A. (1827) Aufzahlung einiger in den osterreichischen Landern gefundenen neuen Gattungen und Arten von Algen nebst ihrer Diagnostik und beigefugten Bemerkungen Regensburg Flora 2: 625 - 646.

Arai, Y. (2010) Attached diatom communities in farmer fish territories. M. S. Thesis, Dept. of Earth and Environmental Sciences, Yamagata University, Japan.

Brun, J. (1894) Especes nouvelles. Le Diatomiste 2 (17): 86 - 88

Hein, M. K., Winsborough, B. M. & Sullivan, M. J. (2008) Bacillariophyta (diatoms) of the Bahamas. Iconographia Diatomologica 19. Gantner Verlag, Ruggell, Germany

Honeywill, C. (1998) A study of British Licmophora species and a discussion of its morphological features. Diatom Research 13: 221 - 271. https: // doi. org / 10.1080 / 0269249 X. 1998.9705450

Konno, S. (2006) Epiphytic Diatoms in Palauan Marine Lakes. M. S. Thesis, Dept. of Earth and Environmental Sciences, Yamagata University, Japan.

Leuduger-Fortmorel, G. (1898) Diatomees marines de la cote occidentale d'Afrique. Memoires de la Societe d'Emulation des Cotes-du- Nord. St. Brieuc. 1 - 41, pl. 1 - 8. https: // doi. org / 10.5962 / bhl. title. 64359

Lobban, C. S., Schefter, M. & Ruck, E. C. (2011) Licmophora flucticulata sp. nov. (Licmophoraceae, Bacillariophyceae), an unusual flabellate species from Guam and Palau. Phycologia 50: 11 - 22. https: // doi. org / 10.2216 / 09 - 85.1

Lobban, C. S. & Schefter, M. (2013) Licmophora comnavmaria sp. nov. (Licmophorales, Bacillariophyta), a new diatom with intercalary rimoportulae. Marine Biodiversity Records 6: e 109. [6 pp.] https: // doi. org / 10.1017 / S 1755267213000869

Lobban, C. S. (2015 a) Benthic marine diatom flora of Guam: new records, redescription of Psammodictyon pustulatum n. comb., n. stat., and three new species (Colliculoamphora gabgabensis, Lauderia excentrica, and Rhoiconeis pagoensis). Micronesica 2015 - 02, 49 pp. [https: // micronesica. org / sites / default / files / lobbandiatomformattedv 2 sm. pdf]

Lobban, C. S., Tharngan, B. G. & Ashworth, M. P. (2018) Four new Licmophora species (Licmophorales), with a review of valve characters and exploration of cingulum characters, including a new septum type. Diatom Research 33: 187 - 217. https: // doi. org / 10.1080 / 0269249 X. 2018.1473292

Macatugal, E. M. S., Tharngan, B. G. & Lobban, C. S. (2019) Three new Licmophora species (Bacillariophyta: Fragilariophyceae) from Guam, two with an axial wave in the valve. Marine Biodiversity Records 12: Article number 4. [13 pp.] https: // doi. org / 10.1186 / s 41200 - 019 - 0161 - x

Sato, S., Watanabe, T., Crawford, R. M., Kooistra, W. H. C. F. & Medlin, L. K. (2008) Morphology of four plagiogrammaceaen diatoms; Dimeregramma minor var. nana, Neofragilaria nicobarica, Plagiogramma atomus and Psammogramma vigoensis gen. et sp. nov., and their phylogenetic relationship inferred from partial large subunit rDNA. Phycological Research 56: 255 - 268. https: // doi. org / 10.1111 / j. 1440 - 1835.2008.00507. x

Williams, D. M. (1988) An illustrated catalogue of the type species in the Greville diatom herbarium. Bulletin of the British Museum (Natural History), Botany Series 18 (1) 1 - 148. [https: // archive. org / stream / bulletinofbritis 81 britlond # page / 100 / mode / 2 up]

Gallery Image

FIGURES 1–6. Plagiogramma subatomus. SEM except Fig. 1 DIC. Fig. 1. Holotype, GU44I-1, Guam. Fig. 2. External view of valve showing spines and apical slits; J5, Jaluit Atoll, Marshall Is. Fig. 3. Internal view showing boxlike pseudoseptum and apical slits, Palau (Konno). Fig. 4. Part of chain showing face to face connections; note the various depths of the copulae (arrow); PW2009-31, Palau. Figs 5, 6. Yap specimens (Y18E) showing internal aspect and a frustule in oblique view; arrow points to copulae. Scale bars: Fig. 1 = 10 µm, Figs 2–6 = 2 µm.

ANSP

Academy of Natural Sciences of Philadelphia

Kingdom

Animalia

Phylum

Arthropoda

Class

Insecta

Order

Coleoptera

Family

Histeridae

Genus

Plagiogramma