The species of the genus Craticula are widely distributed in Europe, mostly occurring in brackish, saline to heavily polluted waters. Some of the species are considered as being most tolerant to pollution. Recently, detailed observations of this genus in Macedonia have been performed. During this study, 15 taxa have been recorded. One of the species (Craticula simplex) was observed with three different morphotypes, which can be distinguished by the valve size and shape. Craticula cuspidata and C. ambigua were the most frequently recorded species in various habitats, while species C. halophila, C. germainii and C. fumantii were observed only on a single locality. The highest diversity of Craticula was observed in temporary ponds on halomorphic soils and mineral springs in Eastern Macedonia.
Background and aims – An increased interest in the diatom flora from subaerial habitats in the Republic of North Macedonia has revealed the presence of a large number of interesting and often unknown, species. During a recent biodiversity survey, seven Muelleria species were recorded, several of which could not be identified based on the available literature.
Methods – Using both Light Microscopy and Scanning Electron Microscopy techniques, the morphology of several Muelleria species has been analysed. The morphology of all taxa is described, illustrated and compared with other possible similar Muelleria taxa, known worldwide.
Key results – Four already documented Muelleria species, M. gibbula, M. islandica, M. terrestris and M. undulata (= Navicula gibbula f. undulata) were identified, while two distinct species are described as new. These new species belong to the M. gibbula complex, and can be differentiated by valve size, stria density, shape of the proximal raphe ends and the shape of external areola foramina. The identity of one taxon remains uncertain due to a low number of observed specimens in the samples. As their ultrastructure is almost entirely unknown, they are briefly discussed.
Conclusions – The diversity of Muelleria in Europe and the North Hemisphere is most likely underestimated and some of the previous records of M. gibbula belong to other species. Observations of diatoms from “extreme” habitats such as intermittent ponds, wet mosses and soils can reveal the existence of interesting and new species.
Adult caddisflies were collected during 2018 and 2019 from Kožuf and Baba mountains, located in the southern end of the Republic of North Macedonia. A total of 36 species were recorded, of which 22 and 8 were recorded for the first time for Kožuf and Baba mountains, respectively. Limnephilus flavicornis (Fabricius, 1787) is reported for the first time from the country from Kožuf Mountain. In addition, new localities of several rare and endemic caddisfly species were found. The results of this study highlight Kožuf and Baba mountains as refugium for caddisfly species of conservation importance.
Lowland intermittent ponds, although biologically important, are poorly studied water habitats. During the analyses of the material taken from lowland pond in Pelagonia Valley, and Vitachevo, Republic of North Macedonia, the diatom Sellaphora pelagonica sp. nov. was recorded and described based on light and scanning electron microscopy. The species is characterized by a strictly linear valve outline with parallel to slightly concave margins and broadly rounded ends, 15.0–40.0 µm long and 5.0–7.0 µm wide. These features, together with raphe structure and areolar shape are compared with several similar taxa currently ascribed to Sellaphora.
The caddisfly species Rhyacophila pubescens Pictet, 1834 is reported from R. North Macedonia for the first time. Our investigations showed the presence of this species at only one locality at Osogovo Mountain, above the Sasa mine. R. pubescens is commonly distributed in Central Europe but has been rarely found in the southeastern parts of the continent. This record marks the southernmost occurrence of this species in the Balkan Peninsula and increases the number of Rhyacophila species of R. North Macedonia to seventeen. The results obtained in our study a) provide information on the distribution of R. pubescens in the Balkan Peninsula; b) comment on the ecological preferences of the species and c) serve as a valuable source of information for further biodiversity and population studies.
A large study on Gomphonema EhrEnbErg species from Macedonia recently has been started. In this article two species are presented having unique set of characters than already known species and therefore are described as new species. The comparison was made using type material of G. brebissonii Kützing and G. gautieri (van hEurcK) LangE-bErtaLot et MEtzELtin. Gomphonema scardicum sp. nov. resembles G. montanum (SchuMann) grunow and G. brebissonii Kützing with respect to the valve outline and size. Main differential characters of G. scardicum are the cuneate shape of the headpole and less pronounced constriction near the head pole. Similarly, G. gautieriforme sp. nov. differs from G. gautieri with respect to the valve outline and the shape of the head pole. The valves of G. gautieriforme are almost rhombic in outline and gradually narrowing towards the footpole. The head pole of G. gautieriforme is rounded and cuneate opposite to truncate and apiculate in G. gautieri.
A new fossil diatom species, Tertiarius minutulus sp. nov., is described from a sediment sequence DEEP-5045-1 of Lake Ohrid. The species is characterized by small valves (3.0–8.0 µm) with a round shape, a marginal area with radially arranged costae and a central uneven area with scattered areolae. Externally, the alveoli are occluded by cribra perforated by irregularly arranged pores. Internally, the alveoli are simple and areolae are occluded with domed cribra. The marginal fultoportulae are situated on costae close to the valve margin, located on every 5th or 7th thick internal costa. One to three fultoportulae are present on the valve face, each surrounded by two to three satellite pores. One rimoportula is present, positioned on a costa at the valve face / mantle junction. The species is compared with morphologically similar taxa and a detailed differential diagnosis is provided. Tertiarius minutulus sp. nov. is known only as a fossil taxon from Lake Ohrid, with a first occurrence during the early stages of lake basin development.
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