Ericaria giacconei Serio & G.Furnari, 2021

Serio, Donatella & Furnari, Giovanni, 2021, Ericaria giacconei sp. nov. (Sargassaceae, Fucophyceae), the species to which the invalidly published Cystoseira hyblaea Giaccone should be referred, Cryptogamie, Algologie 20 (10), pp. 141-151 : 143

Ericaria giacconei Serio & G.Furnari , sp. nov.

( Figs 2-5 )

Thalli caespitose, attached to the substrate by a robust and compact basal disc (3-5 cm in diameter) from which 4-20 cauloids, cylindrical, up to 30 cm high and 3-5 mm in diameter, arise; apex of cauloids smooth, not prominent, never surrounded by spiniform appendages, sometimes surrounded by short cylindrical non-spiny young primary branches; primary branches cylindrical, bearing branches of higher order cylindrical, and with subequal development that give the thallus a cupressoid habit; tophules and aerocysts absent; in cross section, medulla formed by small rounded cells, cortex made of roundish cells with thin walls and meristoderm formed by a layer of rectangular cells twice longer than wide; receptacles terminal, cylindrical-ovoid to clavate, 0.5-1 cm long and 1-2 mm wide, with grouped conceptacles; conceptacles bisexual, subspherical, located at the base of spinous deciduous appendages; oogonia occupying the floor of the conceptacle and antheridia on branched hairs.

HOLOTYPE. — Italy, Straits of Sicily, Porto Palo di Capo Passero, Contrada Guardiana , 36°39’03”N, 15°04’37”E, 0.50 m depth, 11.I.2020, fertile specimen, coll. Serio, ( CAT [ CAT 2716 ] ( Figs 3 , 4 ).

ISOTYPE. — Same data of the holotype; CAT [ CAT 2717, CAT 2718]).

E TYMOLOGY. — The specific epithet honours Professor Giuseppe Giaccone, who first found this species, for his significant contributions to the study of the Cystoseira complex.

TYPE LOCALITY. — Porto Palo di Capo Passero (Sicily, Italy), 36°39’03”N, 15°04’37”E.

DISTRIBUTION. — Type locality; Punta D’Aliga (Sicily, Italy) ( Giaccone 1986 as C. hyblaea ); Isola delle Correnti (Sicily, Italy) ( Pizzuto 1999 as C. crinita ); Kelibia ( Tunisia) ( Bouafif et al. 2016 as C. hyblaea ) ( Fig. 1 ).

HABITAT. — Plants living on semi-exposed rocky shores at 0.2- 1.0 m depth. Species vicariant of E. amentacea ( Giaccone, 1986 as C. amentacea ).

REMARKS

Other figures (as “ C. hyblaea ”): Giaccone (1986, figs 1, 2), Cormaci et al. (2012, pl. 111, figs 1-3), Bouafif et al. (2016, figs 21-24).

Figures

FIG. 2. — Ericaria giacconei sp. nov.: Giaccone’s specimen labelled as Cystoseira hyblaea Giaccone (CAT 74, preserved in glycerine) showing primary branches with a cupressoid outline. Scale bar: 2 cm.

FIG. 3. — Ericaria giacconei sp. nov., holotype: CAT 2716,11.I.2020, Contrada Guardiana (36°39’03”N, 15°04’37”E), Porto Palo di Capo Passero (Straits of Sicily, Italy), 0.50 m depth: A, habit; B, detail of basal crust; C, detail of apex of cauloid. Scale bars: A, 2 cm; B, C, 1 cm.

FIG. 4. — Ericaria giacconei sp. nov.,holotype:CAT 2716:A, cross section showing a medulla formed by small rounded cells, a cortex made of roundish cells with thin walls and a meristoderm formed by a layer of rectangular cells twice longer than wide; B, mature receptacles terminal, with deciduous spinous appendages, conceptacles located at the base of spinous deciduous appendages;C, cross section showing a conceptacle with oogonia occupying the floor of the conceptacle and antheridia forming a ring above them; D, detail of antheridia on branched hairs. Scale bars: A, D, 50 µm; B, 0.5 cm; C, 100 µm.

FIG. 5. — Ericaria giacconei sp. nov. and Sabellaria alveolata (Linnaeus, 1767) from “Porto Palo di Capo Passero” (Sicily): A, overview of the bottom covered by a E. giacconei and S. alveolata biocostructions; B, A thallus of E. giacconei encircled by S. alveolata.

FIG. 1. — Distribution of Ericaria giacconei sp. nov. white circles indicate stations in which the species was previously recorded as Cystoseira hyblaea Giaccone. The white triangle shows the type locality.