Paul B. Hamilton

An examination of species within the genus surirella from the malili lakes, sulawesi island, Indonesia, with descriptions of 11 new taxa

With 35 taxa reported by Hustedt (1942a), the genus Surirella (Turpin) is one of the most taxonomically rich and important genera in the Malili Lakes, a system of five ancient lakes located on the island of Sulawesi, Indonesia. We examine in detail the taxonomy of diatoms within the genus Surirella from the Malili Lakes. We also statistically evaluate valve morphology and relationships among taxa, and describe 11 new taxa. Results show Surirella taxa clustered according to unique combinations of morphological characteristics. Individuals within clusters often shared common valve shape, torsion, and presence of siliceous features including spines, spinules, and novel structures such as siliceous tendrils and tubular processes along the median area. We demonstrate that the siliceous tendrils of Surirella sublinearis and its varieties, and S. tenacis are used for attachment to substrata and further postulate that the evolutionary development of attachment features contributes to the substantial diversity of Surirella taxa in this ancient lake system.

MORPHOLOGICAL OBSERVATIONS OF NEIDIUM SPECIES WITH SAGITTATE APICES, INCLUDING THE DESCRIPTION OF N. CAPE-CODII SP. NOV.

Nedium cape-codii Siver & Hamilton sp. nov. is described from a small glacial kettle lake situated on the Cape Cod peninsula, Massachusetts, U.S.A. Nedium cape-codii is a large diatom with slightly bowed margins, a single longitudinal canal along each valve margin and sagittate apices. Each areola is covered externally by volae and internally with a flat, thin, perforated hymen. In addition, small kidney bean-shaped structures, termed here renilimbi, are associated with specific rows of areolae on the internal valve surface. We also present SEM-based morphological descriptions of N. tokyoense Kobayasi, N. pseudogracilis Kobayasi and N. gracile Hustedt, the three species with sagittate apices morphologically most similar to N. cape-codii, from either type material or new material collected from the type localities. The relationships of N. cape-codii to other species with sagittate apices are also discussed.

Notes on the genus Nupela (Bacillariophyceae) including the description of a new species, Nupela scissura sp. nov. and an expanded description of Nupela paludigena

Two species of the diatom genus Nupela are reported from freshwater lakes situated along the Atlantic Coastal Plain of North Carolina, USA. One of the species, N. scissura sp. nov., is described as new and the description of the other, Nupela paludigena (Scherer) Lange‐Bertalot, is expanded to include a full suite of ultrastructural characters. Nupela scissura is a heterovalvar taxon with one valve having a fully developed raphe identical in structure to those found on other Nupela species. The other valve lacks a true raphe, but presents one to several elongated slits in the apical portion of the sternum. The true identity of the slits, whether they represent a highly reduced raphe, a rudimentary raphe, or neither is unknown. In addition, both valves of a single N. scissura frustule differ in the structure of the axial and central areas. The structure of the areolae and details of the raphe clearly place this species in Nupela. Nupela paludigena (Scherer) Lange‐Bertalot was originally described in the genus Anomoeoneis from acidic and humic localities from the south‐eastern part of the Atlantic Coastal Plain and later transferred to Nupela. Although this species has rarely been reported since its description, our findings indicate that it is a common component of the floras in the Carolina bays of North Carolina. The characteristics currently used to circumscribe taxa within the genus Nupela are discussed in light of published work and our own observations.

TYPIFICATION OF NAVICULA AFFINIS EHRENBERG: TYPE FOR THE NAME OF THE GENUS NEIDIUM PFITZER

Samples from Christian Gottfried Ehrenbergs Collection were studied for the taxon Navicula affinis Ehrenberg. Since Ehrenberg did not designate a type for Navicula affinis at the place of its first description, eleven localities of his 1843 America publication had to be evaluated. Examination of the micas and samples from these localities, combined with the unpublished notations and original line drawings allowed us to verify that samples from the two localities, Newfoundland (Canada) and Bridgewater (Massachusetts, U.S.A.) contained Navicula affinis; a specimen from Ehrenbergs Newfoundland mica preparation was chosen to serve as lectotype. This study emends the description of the species Neidium affine (Ehrenberg) Pfitzer and the genus Neidium Pfitzer using its type species Neidium affine.

New species of freshwater diatoms from acidic localities along the Atlantic Coastal Plain of the United States

During our investigations of freshwater sites along the Atlantic Coastal Plain of North America we had the opportunity to critically study five interesting diatoms with light (LM) and scanning electron microscopy (SEM), each of which is described here as a new species. Two of the organisms are in the genus Eunotia, Eunotia lewisii Siver & Hamilton sp. nov. and Eunotia quadra Siver & Hamilton sp. nov.; two in Frustulia, Frustulia crispula Siver, Pelczar, & Hamilton sp. nov. and Frustulia inculta Siver, Pelczar, & Hamilton sp. nov.; and the last is Neidium trainori Siver & Hamilton sp. nov. All five species are reported from acidic, poorly buffered, dilute waterbodies high in dissolved humic substances. Two of the taxa are found in suites of waterbodies in close geographic proximity, two in somewhat disjunct regions, and the fifth is only known from the type locality. The relationships of each taxon to similar species are discussed.

THE TYPE FOR FRAGILARIA LANCETTULA SCHUMANN 1867 AND TRANSFER TO THE GENUS PUNCTASTRIATA AS P. LANCETTULA (SCHUM.) HAMILTON & SIVER COMB. NOV.

Fragilaria lancettula was described in 1867 by Julius Schumann from freshwater material collected near Königsberg, Prussia. The limited description and presentation of two slightly different original illustrations of the valve form, has created confusion in the literature with published recombinations as varieties under Fragilaria pinnata, Fragilaria mutabilis, and Staurosirell apinnata. With the present examination of Schumanns type material, Fragilaria lancettula is now assigned to the genus Punctastriata with a complete circumscription of the species. This taxon is more common than currently reported and is often associated with Staurosira spp. (including Staurosira construens), Staurosirella pinnata sensu lato, and Pseudostaurosira spp. (including P. elliptica and P. brevistriata).

A Morphological Investigation of Eunotia fennica (Bacillariophyceae) from a Freshwater Acidic Pond in Newfoundland, Canada

ABSTRACT. Eunotia fennica (Hustedt) Lange-Bertalot, originally described as E. denticulata var. fennica Hustedt, was identified in good numbers from a small Orchid Bog Pond, Newfoundland. We investigate the population and valve morphological structure of this taxon using LM and SEM preparations. Additional specimens representing the Eunotia denticulata-complex are identified from five regions across eastern and northern North America and are compared with E. fennica. Current problems in the taxonomy of the E. denticulata complex are explored through an investigation of the original descriptions, and characters used to separate E. denticulata, E. neoborealis and E. fennica are identified. A preliminary examination of water chemistry is also made and related to the taxa. This Orchid Bog Pond is an acidic, poorly buffered, dilute waterbody situated on a sphagnum bog with a selective diatom flora which includes a good population of E. fennica, a taxon presently identified across three continents.

A reevaluation of Aulacoseira nygaardii (Camburn) Camburn & D.F. Charles (Bacillariophyceae): based on scanning electron microscopy of type material

Aulacoseira nygaardii was originally described by Camburn (as Melosira nygaardii in Camburn & Kingston 1986) based on light microscopy. Because the fine structure of this taxon can be difficult to resolve with light microscopy, positive identifications can also be difficult. We present an emended description of this taxon based on an evaluation of type material with scanning electron microscopy (SEM). Although SEM micrographs reported as A. nygaardii were presented by Scherer (1988), our observations indicate that the specimens examined by him possess several characters that differ from those in the type material and may represent a different organism.

Two new species ofNitzschia(Bacillariophyceae) from freshwater environs of Lonar Crater Lake, India: Two newNitzschiafrom India

Diatom taxa in India were first documented by Ehrenberg and subsequently many studies have focused on the Western Ghats and Himalayan mountains while other regional environments were rarely explored. In the current study, the freshwater environs of the saline Lonar Crater Lake were investigated and two new Nitzschia species have been described. Nitzschia kociolekii sp. nov. and Nitzschia tripudio sp. nov. were sampled from bird feeding ponds associated with Lonar Lake. The morphological characters of the new species are similar to N. amphibia and N. frustulum but differ in terms of striae pattern, polymorphic areolae development, fibula and stria density. In addition, larger specimens of N. williamsii, a recently described taxon from Bangalore wetlands of Peninsular India, were found in a waterfalls flowing into Lonar Lake. All three taxa are freshwater diatoms and are possibly endemic to Peninsular India.

Two new species of Nitzschia (Bacillariophyceae) from freshwater environs of Lonar Crater Lake, India

Diatom taxa in India were first documented by Ehrenberg and subsequently many studies have focused on the Western Ghats and Himalayan mountains while other regional environments were rarely explored. In the current study, the freshwater environs of the saline Lonar Crater Lake were investigated and two new Nitzschia species have been described. Nitzschia kociolekii sp. nov. and Nitzschia tripudio sp. nov. were sampled from bird feeding ponds associated with Lonar Lake. The morphological characters of the new species are similar to N. amphibia and N. frustulum but differ in terms of striae pattern, polymorphic areolae development, fibula and stria density. In addition, larger specimens of N. williamsii, a recently described taxon from Bangalore wetlands of Peninsular India, were found in a waterfalls flowing into Lonar Lake. All three taxa are freshwater diatoms and are possibly endemic to Peninsular India.