Haslea meteorou, 2015

Sterrenburg, Frithjof A. S., Tiffany, Mary Ann, Hinz, Friedel, Herwig, Wulf E. & Hargraves, Paul E., 2015, Seven new species expand the morphological spectrum of Haslea. A comparison with Gyrosigma and Pleurosigma (Bacillariophyta), Phytotaxa 207 (2), pp. 143-162 : 152

H. meteorou Hinz & Sterrenburg , sp. nov. ( Figs 16, 17 : LM, 39–46: SEM)

Type:— “ SM338 IOE “Meteor” Sta. # 103, 170-0m, 20-12-1964, geographic coordinates 11°27,5’N 53°04,5’E. Holotype BRM SIM 64 /43, slide coordinates (benchmark left upper corner of coverslip) 13.2 E, 6.0 S, isotype coordinates 15.0 E, 7.3 S.

Valve ( Figs 16, 17 , 39, 40 ) lanceolate, 38–45 μm long, 7–10 μm wide, with acute ends. Striae transverse slightly radiate, 18–20 in 10 μm, longitudinal 14–16 in 10 μm. In LM, axial and central area very narrow. In SEM, the tegumental layer shows little relief ( Figs 41, 44 ). External central raphe fissure endings approximate, tiny “crooks”, tightly curved over about 270° around a tooth-like projection ( Figs 44, 46 ), apical endings undulating and terminate as retrograde depressed hooks ( Fig. 41 ). At the apex 2–3 small accessory pores perforate the solid margin of the valve ( Fig. 41, 42 ). Basal layer: foramina apically elongated oblong, longitudinal bars of the grate much broader than the foramina ( Figs 42, 43 ). Entire internal raphe fissure and central raphe node (which is slightly depressed in the middle) tilted sideways ( Figs 43, 45 ).

Etymology:— The specific epithet, genitive of Greek “meteoros”, refers to the research vessel used by the expedition during which the material was collected.

Habitat:— planktonic, marine.

Distribution:— so far known from the type locality only, fairly rare in the sample.

Observations: —In samples of the Meteor expedition discussed in Simonsen 1974, we found specimens resembling H. tsukamotoi in the peculiar central external raphe ending shapes and fully tilted central raphe node. There is no marked broadening of the internal areolar foramina near the margin, however, and transverse striation is much finer than the longitudinal, warranting separate taxonomic status. Simonsen (1974) does not describe such specimens under either Haslea or Navicula . In the specimen of Figs 41 and 44 valve development is not yet complete: infilling has resulted in narrow fissures at the periphery, but has not yet finished in the median portion of the valve. The specimen of Fig. 43 shows the final situation, with very narrow longitudinal fissures. Saepes not satisfactorily visualized, no fragmented valves found.

H. meteorou has much coarser longitudinal than transverse striae, setting it apart in the genus Haslea .

Figures

FIGURES 10–20. New Haslea species, LM images (DIC).All bars = 10 μm. All except Fig. 11 are stacks of 12–22 separate images. FIGURES 10, 11. H. staurosigmoidea sp. nov. Fig. 10. Holotype, Fig. 11. Isotype, aspect in normal DIC corresponding to what is seen on visual inspection.

FIGURES 39–46. H. meteorou sp. nov. SEM, isotypes. Fig. 39. General aspect, exterior, bar = 5 μm. Fig. 40. General aspect, interior, bar = 5 μm. Fig. 41. Apex, exterior, bar = 2 μm. Note apical pores (arrow). Valve morphogenesis not yet complete, fissures to be filled in. Fig. 42. Apex, interior, bar = 2 μm. Note apical pores (arrow). Fig. 43. Centre, interior, bar = 2 μm. Fig. 44. Centre, exterior, bar = 2 μm. Fig. 45. Detail of Fig. 43, 2x enlargement. Note sideways tilted central raphe node. Fig. 46. Detail of Fig. 44, 2x enlargement. Note crook-shaped raphe endings.