Pleurocapsa fuliginosa Hauck 1885

Shalygin, Sergei, Kavulic, Katherine J., Pietrasiak, Nicole, Bohunická, Markéta, Vaccarino, Melissa A., Chesarino, Nicholas M. & Johansen, Jeffrey R., 2019, Neotypification of Pleurocapsa fuliginosa and epitypification of P. minor (Pleurocapsales): resolving a polyphyletic cyanobacterial genus, Phytotaxa 392 (4), pp. 245-263 : 253-257

Pleurocapsa fuliginosa Hauck 1885

Description of our material: —( Figs. 1A, B , 4A ) Colony dark blackish brown, hard, dry, in discrete small clumps, arising from the substrate, consisting of large sarcinoid clusters of coccoid cells, with pseudofilament production uncommon, not obviously divaricately branching, but sarcinoid divaricating clusters may expand outward as they divide radially from a central point, forming compact disc-like expanses. Sheaths colorless, thin, tight, scarcely apparent. Pseudofilaments uni- or multiseriate, 4–8 μm wide when uniseriate, up to 20 μm wide in multiseriate filaments. Cells spherical or more commonly ovoid with sides appressed by neighboring cells, typically in large sarcinoid packets, at first the color of red wine, becoming bluish gray, with mature cells russet-brown to dull copper-brown, with thin cross walls, with few but distinct spherical granules, diameter (2) 4–17(20) μm, sometimes individual cells becoming rounded, enlarged, up to 25 μm in diameter. Chromoplasm often appearing in a parietal position. Baeocytes uncommon, rounded, 3–3.5 μm in diameter.

Collection locality:— Maunawili stream, approximately 20 minutes hike downstream from Maunawili Falls, Oahu. 21° 21’ 05”N latitude, 157° 46’ 08”W longitude; July 25, 2009.

Holotype:— Possibly in the Musée d’Histoire naturelle, Paris, according to Komárek (1972). Not available for external loan. Material from North America Illustrated in Komárek & Anagnostidis 1998, Fig. 622 c, p. 472.

Neotype here designated:— BISH 755070 , Bernice Pauahi Bishop Museum , Honolulu, Hawaii, USA., herbarium mount prepared from the strain, HA4302- MV1 .

Reference Strain:— HA4302- MV 1, John Carroll University Culture Collection, University Heights, Ohio, USA.

Taxonomic notes:— P. fuliginosa was originally described from limestone in the intertidal zone of the Adriatic Sea near Trieste, Italy by Hauck (1885) and a specimen was deposited in Thuret´s collection in the Musée d’Histoire naturelle, Paris. Here is original Hauck’s description of P. fuliginosa :

“Macrocolonies as blackish aggregates. Cells 5–20 μm wide, single or 2–4 celled, in the large subcolonies up to 50–100 μm. Cell golden-brown, reddish to dirty violet, sometimes blackish, cell content homogeneous. Envelopes colorless”.

However, none of the three deposited specimens which are available on the official web site Musée d’Histoire naturelle, Paris fit the type locality of the species. They all originate from different marine environments in North America. Some of them, such as P. fuliginosa MNHN-PC-PC0560503, were originally determined as Coccochloris deusta Meneghini (1841: 173) which is an earlier name for Entophysalis deusta (Menegh.) Drouet & Daily (1948: 79) . Members of that genus are incapable of baeocyte production. Komárek (1972) most likely examined one of the three specimens which were mentioned to be epiphytic on the marine macroalgae, in contrast to the original material of Hauck who described P. fuliginosa from the stony intertidal. Here is an excerpt from correspondence with Prof. Jíři Komárek concerning P. fuliginosa sent in 2017:

“I have studied the type material of Pleurocapsa fuliginosa almost 50 years ago in the laboratory of Prof. Bourrelly in Paris. As I remember, we have studied there with Prof. Bourrelly the isotype material of Pl. fuliginosa , which was originally from Thuret´s collection and was deposited in the herbarium of Musée d’Histoire naturelle, Paris. I have studied these types just with the supervision and initiative of Prof. Bourrelly. Unfortunately, I do not remember the locality of the original Haucks material, because I was oriented mostly on my strains in that time, which are described in my short study. Prof. Bourrelly gave me this type material only for comparison and it was my omission that I did not describe better this original Haucks specimen. However, maybe that this type material is still deposited in cryptogamic herbarium in Paris, where the original locality should be found.”

Unfortunately, Musée d’Histoire naturelle, Paris does not allow loan or use of biomass for molecular investigation of type materials for algae. Given the fact that the museum catalogue does not have material from the type locality or type substrate, we question whether or not the type is actually in the collection. Subsequently, following ICN (Article 9.7, ICN) we consider type materials of Pleurocapsa fuliginosa as being lost, and consequently we are establishing a neotype for that particular species, which is the type species of the genus.

The strain HA4302- MV 01 which have been primarily characterised by Sherwood et al. (2014) exactly fits the morphological description and illustrations of the original description given by Hauck (1885). In particular, the sarcinoid radiating colony is identical, cell dimensions are the same, and the color of the cells are all a close match ( Figs. 1 , 3A ). The dirty-violet (wine red) color is only found in this species of Pleurocapsa . The only difference we can detect is in ecological habitat. P. fuliginosa occurs in brackish (e.g. Baltic Sea) to marine (e.g. Adriatic Sea) waters, whereas our strain is only in freshwater in Hawaii. However, the sample from which our P. fuliginosa derived was collected in a Maunawili stream which is <5 kilometers from the coast. We are making the assumption that the neotype population could ultimately have had a marine origin.

Class Cyanophyceae

Subclass Oscillatoriophycidae

Orber Pleurocapsales

Family Pleurocapsaceae

Pleurocapsa minor HANSGIRG 1891

Synonym: — Scopulonema minus (Hansgirg) Geitler (1942: 93)

Description of our material: —( Figs. 4 B , 5 ) Colony compact, olive-brown, soft to hard, dry, in clumps or small irregular mounds, arising from the substrate with extensions that are higher than wide, consisting of aggregates of coccoid cells, in diads or tetrads, but not forming large cubical sarcinoid clusters, containing pseudofilamentous, pseudodichotomously branching aggregates, united laterally by the confluence of thin gelatinous sheaths. Sheaths colorless, thin, scarcely apparent, later, in the older stages, more robust with yellowish-orange color. Pseudofilaments uni- or biseriate, 5–12.5 μm wide, with rounded end cells lighter in color than central cells, 4–10 μm wide, 3.5–22 μm long. Cells of the central portion of the thallus irregular, with binary to multiple fission, but mainly sarcinoid, dark olive-green, brown, to brownish orange in older parts of colony, nongranular, with reticulate nature of the cytoplasm often evident, 2.5–10 μm wide, up to 11.5 μm long. Baeocytes uncommon, 1.4–2.8 μm in diameter.

Collection localities: — GSE-CHR-MK-17-07 R: Lower Calf Creek Falls , Grand Staircase-Escalante National Monument , Utah, USA. Growing in algal mats on sandstone continually wetted by a waterfall. 37° 49’ 44.77” N latitude, 111° 25’ 12.58” W longitude, August 16, 2006 ( Fig. 2B ). HA4230: Nuuanu Pali Lookout , HWY 61, Oahu, USA. Growing on cement trail by the cement wall. 21° 22’ 01” N latitude, 157° 47’ 31” W longitude ; July 23, 2009.

Holotype: — Hansgirg (1891), as a pressed isotype specimen stored in the Department of Botany Collection , housed in the Smithsonian National Museum of Natural History, Washington, USA.

Epitype here designated: —dried material BISH 751766 is derived from HA4230- MV 1, Bernice Pauahi Bishop Museum, Honolulu, Hawaii, USA.

Reference Strain: —HA4230- MV 1, John Carroll University Culture Collection, University Heights, Ohio, USA.

Taxonomic notes:— Our strains are an excellent fit to the morphological description of Pleurocapsa minor Hansgirg (1891) , and the subsequent expanded description of Geitler (1932). P. minor is typically found in waterfalls. P. minor HA 4230- MV 1 has a genetic identity of 98.8–99.0% to P. minor GSE-CHR-MK17-07 R ( Fig. 5 ), but is ≤98.7% similar to to all other species in our Pleurocapsales clade (98.0–98.3% similarity to P. fuliginosa , ≤96.8% similarity to all other taxa in the phylogeny).

Figures

FIGURE 1. Line drawings of the type species of genus Pleurocapsa, P. fuliginosa: (A) Copy of P. fuliginosa from original publication (Shalygin after Hauck 1885); (B) Original images of P. fuliginosa from the neotype from Hawaii archipelago (cultural material) with additional morphological trait-pseudofilaments. Scale bar equals 10 μm.

FIGURE 2. Collapsed 16S rRNA gene phylogeny of Pleurocapsales based on 253 OTUs with maximum length of 1,483 bp. Support values are shown as BI. Nodes lacking support are indicated by “–”. The entire uncollapsed tree can be found in the Supplementary Materials as Fig. S1. Strains we consider to be correctly identified and representative of the genus are followed by an asterisk. Taxa which need revision are placed in the quotes.

FIGURE 3. Secondary structures of conserved domains in the 16S–23S ITS region. A–G. D1-D1’ helices for four strains; alternative structures for the same strain are indicated with equilibrium arrows. H–J. V2 helices situated between tRNAIle and tRNAAla genes. K–M. Box-B anti-terminator helix. N–O. End region of 16S–23S ITS showing D4 helices (yellow), V3-helices (purple), D5 region (green), and position of attachment of 23S rRNA gene within the D5, with 3’ end of 16S–23S ITS paired to 5’ end of 23S–5S ITS.

FIGURE 4. Light photomicrographs of Pleurocapsa spp.: (A) P. fuliginosa from neotype material, note pseudofilaments as well as peripheral and irregular thylakoid arrengment; (B) P. minor from Grand Staircase-Escalante National Monument (cultured isolates), with classical morphology for that taxon, which is formation of long pseudofilaments, and pseudodichotomous branchings. Scale bar equals 10 μm.

FIGURE 5. Light microphotographs of the epitype of the Pleurocapsa minor HA4230-MV1 from Hawaii: (A) Stages of germination; (B) Young subcolonies, derived from baeocytes, and initial stages of pseudodichotomously branched pseudofilaments (indicated with arrow); (C) Mature stages with defined rows of the cells, and clear pseudodichotomous branches; (D) Older stages with yellowish-orange, more or less robust sheaths. Scale bar equals 10 μm.