Bulbostylis cangae, a new species of Cyperaceae from Northern Brazil (Serra dos Carajás, Pará State)

Bulbostylis cangae is a new species of Cyperaceae, thus far only known for the cangas of the Serra dos Carajás (Pará State, Brazil), herein described and illustrated. We provide a detailed description, taxonomic comments, distribution data, habitat, and conservation status of the species. Bulbostylis cangae is characterized mainly by presenting a thickened base, forming a caudex covered by persistent senescent sheaths. The new species is morphologically similar to Bulbostylis medusae, but differs by presenting trichomes on the sheath apex castaneous, glumes membranaceous, cordiform achene and discoid stylopodium.

Oomycete and chytrid infections of the marine diatom Pseudo-nitzschia pungens (Bacillariophyceae) from Prince Edward Island, Canada

Two eukaryotic parasites were found infecting the bloom-forming marine diatom Pseudo-nitzschia pungens (Grunow ex Cleve) Hasle in Prince Edward Island, Canada. The most common was an oomycete; the other, seen once, was a chytrid. The structure of the discharged sporangium of both is remarkably similar. The oomycete parasite caused the host cell to lay down several extra girdle bands as the parasite thallus grew and swelled to form a holocarpic, endobiotic, nonwalled multinucleate thallus within the host cytoplasm. At maturity the thallus formed a single discharge tube with a thickened base and a thin papillate apex. Many biflagaellate zoospores were formed that burst out from the discharge tube. Ultrastructural characteristics of the oomycete thallus include mitochondria with tubular cristae and vesicles with dense body inclusions, features common to the oomycetes. The morphological characteristics and biflagellate condition indicate a placement of this form in the genus Ectrogella . However, neither flagellar mastigonemes nor flagella flimmer vesicles were found. The absence of flimmers may indicate a closer phylogenetic relationship to Haptoglossa , an endoparasitic oomycete of nematodes, the zoospores of which lack flagellar mastigonemes. Cell infection frequencies ranged from 0.6%–15.9% during 1992–1995, at the four sampling sites.

On a New Fish-Jaw from the Gault Near Folkestone

My friend Mr. Mackie has handed me an interesting little fragment of jaw, derived from the Gault at Folkestone. The length of the broken fragment of jaw measures 1⅛ inch; its absolute breadth of an inch. It contains three teeth, of which the largest is conical, incurved, exhibiting around its thickened base a series of sculptured linear depressions, parallel with the axis of the tooth, the interior of which has been converted into phosphate of lime; the second and the third also exhibiting similar characters, the third especially being acuminate, and exhibiting the natural apex of the tooth in an uninjured state. The conformation of such a tooth led my friend Mr. Davies to compare it with the homologous structure in the teeth of the Pachyrhizodus basalis of Agassiz, which is described by Sir Philip Egerton, F.R.S., in Mr. F. Dixon's ‘Geology of Sussex.’ The specimen figured in that work was obtained from the Lower Chalk at Steyning. The characters, which are given, are—” apex very brittle, slightly curved inwardly, and solid; the base is hollow, and extends into the substance of the jaw.” It is further stated that in Sir Philip Egerton's cabinet there is a specimen of this fish, exhibiting an unusually thick and strong humerus, as well as large and circular scales, covered with asperities so minute as to be indistinguishable without the aid of a glass.There are many points of distinction, however, between the Pachyrhizodus basalis of Agassiz, and Mr. Mackie's specimen. Apart from the absolute size of Mr. Dixon's specimen, which is at least double that of the one before me, I am wholly unable to detect in the former any trace of that curious sculptured channelling which is so prominent in the latter specimen. This comparison failing, Mr. Davies showed me some most interesting specimens, also from the Folkestone gault, which exhibited equally perfect evidences of this sculpturing. I would therefore suggest that some temporary or provisional name should be given to this form, which differs from the Pachyrhizodus basalis of Agassiz, both in its stratigraphical habitat and its odontological conformation.