Parviphycus bompardii A. Bottalico, C. Russo, G. Furnari & C. Perrone, 2015

Bottalico, Antonella, Russo, Christian, Furnari, Giovanni & Perrone, Cesira, 2015, Parviphycus bompardii sp. nov. and P. albertanoae (Gelidiales, Rhodophyta), two species misidentified as Gelidiella ramellosa in the Mediterranean Sea, Phytotaxa 219 (2), pp. 155-164 : 159

Parviphycus bompardii A. Bottalico, C. Russo, G. Furnari & C. Perrone , sp. nov. (Figs 5–7, 8–19)

Thallus consisting of terete prostrate stolons, attached to the substratum by independent rhizoids, and compressed uprights, 6–18 (20) mm high and 140–320 μm wide, sparsely and subpinnately branched up to the second order; lateral branches are inserted at approximately 90° on main axes ( Figs. 8–9 ). The apical parts are usually covered by hairs ( Fig. 10 ). Erect and prostrate axes grow from a dome-shaped apical cell undergoing transverse divisions; the subapical cells divide distichously ( Fig. 11 ); the outermost cortical cells are polyhedrical, isodiametric (up to 10 μm in diam.) and irregularly arranged throughout in surface view ( Fig. 12 ). In the erect axis transection, a central row of 7–9 medullary cells (20 μm in diam.), axials and periaxials, are always evident ( Fig. 13 ); in longitudinal section, the medullary cells (45–50 μm long), are well distinct from the isodiametric cortical ones ( Fig. 14 ). No internal rhizoidal filaments were found in the whole thallus. Compressed to flattened tetrasporangial sori are more often in lateral stichidium-like branchlets (up to 220 μm wide), constricted at their bases and inserted at 90° on the axes by short stalks; sometimes apical in summer ( Figs 15–16 ). The tetrahedrally divided subspherical tetrasporangia (up to 34 μm in diam.) are regularly arranged in 10–20 chevrons, 4–6 per row; a steril margin is always present ( Fig. 17 ). In empty sori, the cortical cells surrounding the hollow portions through which the sporangia are discharged can be observed in surface view ( Fig. 18 ), whereas longitudinal median sections show the regular cubic-mesh network of medullary cells ( Fig. 19 ). Regenerated tetrasporocysts occasionally occur ( Fig. 18 ). No other reproductive structures were found.

Type: — ITALY. Liguria: San Giuliano’s beach (Genoa), 44° 23’ 30’’ N, 8° 57’ 50’’ E, coll. Bompard, 1868 (holotype FI! 5607, Erbario Crittogamico Italiano ser. II, No. 175, as Acrocarpus spinescens Kützing , tetrasporic specimens) (Fig. 5).

Paratypes: — Castelluccio (Syracuse, Sicily, 37° 18’ 20’’ N and 15° 8’ 28’’ E) CAT! 71 (as G. ramellosa , formalin-preserved, tetrasporic specimens) ( Fig. 8 ), coll. G. Furnari , 10 August 1974 (isoparatype BI! 38466, formalin-preserved) ; Mola di Bari ( Bari , Apulia, 41° 04’ 00’’ N and 17° 05’ 00’’ E) BI! 38467 (as G. ramellosa , formalin-preserved, tetrasporic specimens) ( Fig. 9 ), coll. C. Perrone, 12 August 1999 .

Distribution: —Genoa ( Italy), Castelluccio (Syracuse, Italy), Mola di Bari (Bari, Italy), Tour Fondue (Giens, France) (for the last locality, see below).

Etymology: —The specific epithet bompardii refers to Enrico Bompard, the collector of the first sample of the new species.

The other specimens examined, viz. those collected by Feldmann in 1931 at Kerkennah ( Tunisia) ( Figs 20–23 ) and those from the Cheradi Islands (Taranto, Apulia, Ionian Sea) ( Figs 24–26 ) bore all the characters of the already described species Parviphycus albertanoae . They showed, indeed, a suite of characters that confirm this attribution: compressed uprights (1–1.3 cm high and 100–200 μm wide) subdistichously branched up to the first order; subapical cells distichously dividing ( Fig. 21 ); the outermost cortical cells (5–6 μm in diam.) longitudinally aligned only in the subapical region, but irregularly arranged below, as seen in surface view; 3–5 cells (the axial and periaxials) aligned in the median plane, as seen in the erect thallus transverse section ( Figs 22, 25 ); tetrasporangial sori clavate, mostly apical on main axes and lateral branches; tetrasporangia arranged in transverse rows, usually 4 per row visible in surface view; no sterile margins present ( Figs 23, 26 ).

Figures

FIGURES 8–19. Parviphycus bompardii sp. nov.. Fig. 8. Paratype (CAT! 71) (Castelluccio, Syracuse, Sicily). Scale bar = 3 mm. Fig. 9. Paratype (BI! 38467) (Mola di Bari, Bari, Apulia). Scale bar = 4 mm. Fig. 10. Apical part of an erect axis covered by hairs (paratype CAT! 71). Scale bar = 155 μm. Fig. 11. Apex of an upright branch showing the distichous pattern of division of the subapical cells (isoparatype BI! 38466). Scale bar = 30 μm. Fig. 12. Irregularly arranged outermost cortical cells in surface view (paratype CAT! 71). Scale bar = 8 μm. Fig. 13. Transverse section of a compressed upright branch; seven cells (axial and periaxials) are aligned along the major axis in an evident row (paratype BI! 38467). Scale bar = 50 μm. Fig. 14. Longitudinal section of an erect axis: elongated axial and periaxial filaments composing the medullary region are well distinct from the isodiametric subcortical cells (paratype BI! 38467). Scale bar = 50 μm. Fig. 15.Apical and lateral tetrasporangial sori inserted at 90º on the axes (paratype BI! 38467). Scale bar = 650 μm. Fig. 16. Stichidium-like tetrasporangial branchlets constricted at their bases and shortly stalked (paratype BI! 38467). Scale bar = 230 μm. Fig. 17. Tetrasporangial sorus with tetrasporangia regularly arranged in chevrons (6 per row) and a steril margin (paratype CAT! 71). Scale bar = 100 μm. Fig. 18. An empty sorus in surface view: in the gaps of the outer cortex the tetrasporangium basal cells are visible (arrow). Regenerated tetrasporocysts (arrowhead) (paratype BI! 38467). Scale bar = 60 μm. Fig. 19. Longitudinal section of tetrasporangial sorus along the medullary row of axial and periaxial filaments forming a cubic-mesh network (paratype BI! 38467). Scale bar = 60 μm.

FIGURES 20–26. Mediterranean herbarium specimens of Parviphycus albertanoae, previously misidentified as Gelidiella ramellosa. Figs 20–23. Herbarium specimens (MNHN! PC-PC0167206) from Kerkennah, Tunisia. Fig. 20. Herbarium sheet. Scale bar = 2.5 cm. Fig. 21. Apex of an upright branch of a specimen showing the distichous pattern of division of the subapical cells. Scale bar = 30 μm. Fig. 22. Transverse section of a compressed upright branch; five cells (axial and periaxials) are aligned along the major axis in an evident row. Scale bar = 27 μm. Fig. 23. Tetrasporangial sorus with tetrasporangia regularly arranged in transverse parallel rows (four per row). Scale bar = 180 μm. Figs 24–26. Herbarium specimens from the Cheradi Islands (CAT 1270). Fig. 24. Habit. Scale bar = 3 mm. Fig. 25. Transverse section of an erect axis. Scale bar = 17 μm. Fig. 26. Detail of a tetrasporangial sorus. Scale bar = 50 μm.