Friday, December 2, 2016

[Botany • 2014] Gracilaria lantaensis • A New Flat Gracilaria (Gracilariales, Rhodophyta) from the Andaman Coast of Thailand


Gracilaria lantaensis 
 Muangmai, Zuccarello, Noiraksa & Lewmanomont 


Collection of a flat red alga of the genus Gracilaria from the Andaman coast of Thailand was described as a new species, Gracilaria lantaensis sp. nov. based on detailed morphological characteristics and rbcL sequence analysis. This species typically grew intertidally on exposed mud-sand shores. It was characterized by its slender thalli with narrow-bladed branches, its smooth margin with a few brachlets and its reddish-pink color. Spermatangial conceptacles were of the textorii-type. Cystocarps were spherical and possessed numerous nutritive filaments at lateral and basal positions in the cystocarp cavity. Gracilaria lantaensis was morphologically similar to G. yamamotoi but differed in branching pattern and cystocarp structure. RbcL sequence data also indicated the genetic distinction between G. lantaensis and other species of Gracilaria. Gracilaria lantaensis was grouped with a major assemblage of Gracilaria species, and sister to some Indian Ocean species with denticulate margins, e.g. G. beckeri, G. capensis and G. denticulata.

Key Words: Gracilaria lantaensis sp. nov, Gracilariales, Indian Ocean, rbcL, Rhodophyta, Thailand


DIAGNOSIS: thalli solitary, flattened and erect, 2–11 cm long and 1–6 mm wide, arising from discoid hold fast with a stipe, 2–10 mm long.Blades had smooth margins with few branchlets, irregularly di- ortrichotomous branched and 250–450lm thick. Spermatangial conceptacles were scattered throughout the blade, forming shallow pits,textorii-type. Mature cystocarps were spherical, slightly rostrate and constricted at their base. Nutritive filaments mostly lateral andbasal, connecting to a thick pericarp. Carposporangia in unbranched chains. Tetrasporangia cruciately divided and scattered over the blade.


HOLOTYPE: KUMF-LT 02-016-1, collected 15 April 2012, deposited at Kasetsart University Museum of Fisheries (KUMF) (see Fig. 1).
ISOTYPES: KUMF-LT 02-016-2, KUMF-LT 02-016-3, KUMF-LT02-016-4, KUMF-LT 02-016-5, collected 15 April 2012, deposited at Kasetsart University Museum of Fisheries (KUMF).


TYPE LOCALITY: 7838054.1100N, 9981014.5100E; attached to pebbles or shells on the muddy sand area in the intertidal, 1–2 m deep, at Ao Kaw Kwang, Lanta Island, Krabi Province, Thailand (Fig. S1).

ETYMOLOGY: lantaensis refers to the locality of Lanta Island where this species is found.

Narongrit Muangmai, Giuseppe C. Zuccarello, Thidarat Noiraksa and Khanjanapaj Lewmanomont. 2014. A New Flat GracilariaGracilaria lantaensis sp. nov. (Gracilariales, Rhodophyta) from the Andaman Coast of Thailand.
Phycologia. 53(2); 137-145. DOI:  10.2216/13-215.1

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