Adlafia tjibaoui Le Cohu, Marquié & Coste, 2018

Marquie, Julien, Cohu, Rene Le & Coste, Michel, 2018, Adlafia moseri and A. tjibaoui two new diatom species (Bacillariophyta) from New Caledonia with further observations on Adlafia muscora and Kobayasiella saxicola, Phytotaxa 357 (1), pp. 41-51 : 45

Adlafia tjibaoui Le Cohu, Marquié & Coste sp. nov. ( Figs 19−28)

LM ( Figs 19−24): Valves linear with narrowly rostrate apices in larger specimens and shortly protracted, rounded apices in smaller individuals. Valve dimensions (n=25): length 8.5−14.5 μm, width: 3.0−3.5 μm, ratio length/width 2.9−4.3. Axial area linear. Raphe hardly visible in LM. Striae not discernible in LM.

SEM ( Figs 25−28): Axial area narrow, less than 1/8 of total valve width, linear throughout entire length ( Fig. 25). Striae, 42−44 in 10 μm, composed of externally occluded, quadrangular areolae ( Figs 25, 26), clearly radiate between center and Voigt faults, convergent thereafter ( Figs 27, 28, arrows). Two shortened striae present in central area ( Fig. 27). External raphe branches slightly curved. Proximal raphe endings deflected to primary side ( Figs 25, 26). Terminal raphe fissures strongly bent to secondary side, not extending onto valve mantle ( Fig. 26). Internally, raphe fissures straight, proximal raphe endings shortly deflected towards primary side, distant from each other. Distal raphe endings terminating onto small helictoglossae ( Figs 27, 28).

Type: —Tade: municipality of Ouegoa, NEW CALEDONIA. (20.404517° S, 164.453733° E), benthic periphyton, Julien Marquié, June 2013 (holotype: PC! slide no. 01455191, isotype: BR! Slide no. 4482).

Etymology: —The new species is dedicated to Mr. Jean− Marie Tjibaou, defender of the rights of the native Kanak people of New Caledonia.

Distribution and ecology: — Adlafia tjibaoui was only observed in the Panié massif region, in the north of New Caledonia, outside the ultramafic area (i.e., on volcano-sedimentary substrates). The area is famous for its highly endemic flora and fauna ( Tron et al. 2013). Little is known about the water chemistry of this region except that the water is poor in nutrients with a very low specific conductance ( Weninger 1968). The major accompanying taxa include Gomphonema lagenula Kützing (1844: 85) , Encyonema silesiacum (Bleisch in Rabenhorst 1861–1882, no. 1802) D.G.Mann (1990: 667), Achnanthidium sp. ( A. aff. catenatum ( Bily & Marvan 1959: 34–35) Lange-Bertalot (1999: 277) . Due to possible misidentification in LM with other Adlafia species, the occurrence of the taxon is not clearly known.