Dasya sylviae C.W.Schneid., M.M.Cassidy & G.W.Saunders, 2021

Schneider, Craig W., Cassidy, Margaret M. & Saunders, Gary W., 2021, The pseudodichotomous Dasya sylviae sp. nov. (Delesseriaceae, Ceramiales) from 60 - 90 m mesophotic reefs off Bermuda, European Journal of Taxonomy 751, pp. 24-37 : 28-32

publication ID	https://doi.org/ 10.5852/ejt.2021.751.1377
DOI	https://doi.org/10.5281/zenodo.4818543
persistent identifier	https://treatment.plazi.org/id/5772B54C-4B75-BE69-4CC2-0E51FB87E308
treatment provided by	Felipe
scientific name	Dasya sylviae C.W.Schneid., M.M.Cassidy & G.W.Saunders
status	sp. nov.

Treatment

Dasya sylviae C.W.Schneid., M.M.Cassidy & G.W.Saunders sp. nov.

Fig. 2 View Fig

Diagnosis

Differing from most species of Dasya by its pronounced pseudodichotomous branching pattern ( Fig. 2A– C View Fig ), and from its most similar congener in habit, D. crouaniana J.Agardh , by its longer pseudolaterals, narrower and shorter tetrasporangial stichidia and axes fully covered with pseudolaterals to barely denuded proximal axes. The new taxon differs from all species of Dasya by its lack of post-sporangial cover cells.

Etymology

The species is named after Dr Sylvia A. Earle, pioneering phycologist, scientist and open-water diver, 50 years after she led the first all-female team of aquanauts in Tektite II on the floor of the Caribbean Sea ( Earle 1972 a, 1972b).

Material examined

Type

BERMUDA • Spittal , south of Cooper’s I. off Castle Harbour; 31°19.23333′ N, 64°39.53333′ W; depth 63.8 m; on rhodoliths; 11 Aug. 2016; Schneider & Popolizio 16-21-14; GenBank nos: MW698721 View Materials (holotype), MW699769 View Materials (isotype); holotype ( Fig. 2A View Fig ): MICH [ BDA2031 View Materials ]; isotypes ( Fig. 2B–C View Fig ): Bermuda Natural History Museum, MICH, NY, UNB, US, Herb. CWS [ BDA2030 ]. GoogleMaps

Additional material

BERMUDA • Ledge north northeast of St. George’s I.; 32°28.79600′ N, 64°35.68833′ W; depth 90 m; 28 Jul. 2016; Schneider & Popolizio 16-11-1, ⊕ [ BDA1969 ] GoogleMaps • loc. cit.; depth 60 m; 28 Jul. 2016; Schneider & Popolizio 16-11-10 [ BDA1982 ] • loc. cit.; 32°28.96200′ N, 64°35.25183′ W; depth 90 m; 29 Jul. 2016, Schneider & Popolizio 16-12-2 [ BDA1992 ] GoogleMaps • Spittal, offshore of Midocean Point; 32°19.20000′ N, 64°39.48333′ W; depth 62.7 m; 3 Aug. 2016; Schneider & Popolizio 16-17-2 [ BDA2011 ]. GoogleMaps

Description

Plants epilithic, erect to 17 cm tall, carmine red, arising from small discoidal holdfasts; indeterminate axes sympodially branched, appearing pseudodichotomously branched throughout, only slightly tapering from base to apex ( Fig. 2A–C View Fig ), 0.3–0.8 mm diam. in median to lower portions and completely corticated by rhizoidal downgrowth ( Fig. 2D View Fig ); indeterminate axes densely covered throughout with determinate, lightly pigmented, monosiphonous dichotomously branched axes (pseudolaterals; Fig. 2E View Fig ), except in some older plants in the most basal portions; pseudolaterals 1.7–5.5 mm in length, 25–91 cells from base to apex, irregularly dichotomously branched from the first to the seventh cell of the pseudolateral, upper portions unbranched and slightly tapering ( Fig. 2E View Fig ); basal cells of pseudolaterals initially globose to ellipsoid ( Fig. 2D View Fig ), 21–37 µm diam. and 12–30 µm long, then slightly elongating; suprabasal cells 19–32 µm diam. and 8–32 µm long, elongating more centrally, 9–22 um diam. and 27–102 µm long, and reaching greatest lengths distally, 8–19 µm diam. and 32–127 µm long; tetrasporangial stichidia single, borne terminally on 3–7-celled unbranched pseudolaterals ( Fig. 2F View Fig ) or terminating basal dichotomies of pseudolaterals ( Fig. 2G View Fig ), lanceolate to narrowly elliptical in outline ( Fig. 2F–G View Fig ), 73–80 µm diam. and 269–305 µm in length at maturity, composed of 10–12 fertile segments, acropetally producing then releasing sporangia ( Fig. 2F–G View Fig ); sporangia globose, 21–29 µm diam., tetrahedrally divided, 3–5 per fertile segment, sporangia borne on 2-celled whorled branches, post-sporangial cover cells lacking ( Fig. 2F View Fig ); one to two spermatangial stichidia terminating a basal dichotomy on 4–10-celled pedicels (pseudolaterals), narrowly elliptical to lanceolate in outline ( Fig. 2H View Fig ), 46–69 µm diam. and 192–258 µm in length at maturity; carpogonial branches and cystocarps unknown.