NAUČNI RADOVI


1) Luketa S. 2012. New views on the megaclassification of life. Protistology, 7(4): 218-237. PDF

Abstract: This paper provides a review of the existing literature about megaclassification of the living beings. Novel classification system is introduced, including 5 dominions and 17 kingdoms. In addition, a new nomenclature of higher taxa has been proposed with a premise that the dominion names end with a suffix "-biota", subdominions with a suffix "-konta", kingdoms with a suffix "-ida" and subkingdoms with a suffix "-ides". Dominion Prionobiota comprises acellular organisms without nucleic acid, acellular organisms with nucleic acid have been classified in dominion Virusobiota, dominion Bacteriobiota consists of typical prokaryotic organisms, and dominion Archaebiota comprises specific organisms of prokaryotic structure, whereas dominion Eukaryobiota entails all living beings with eukaryotic organization.



2) Luketa S. 2015. Description of the family Padaungiellidae and morphological variability of Padaungiella lageniformis (Amoebozoides: Arcellinida) from the Vlasina Lake area, Serbia. Archives of Biological Sciences, 67(4): 1331-1337. PDF

Abstract: Based on theoretical conclusions, a new family of testate amoebae, Padaungiellidae, is described. It includes three genera: Alocodera, Apodera and Padaungiella. The most striking characteristic of the members of this family is an elongated neck, and absence of sets of teeth and septa along the oral-aboral axis on the inner side of the neck. The most common species of this family is Padaungiella lageniformis. Morphometrically, this species is not analyzed yet, so the qualitative and quantitative characters of a sphagnicolous population of P. lageniformis from the Vlasina Lake area (Serbia) are reported here. Quantitative characters were analyzed by univariate statistical methods. Coefficients of variation were moderately low for all the measured characters (range from 4.37 to 10.71%). Frequency distribution of only seven of sixteen variables showed approximately zero level of kurtosis, which indicated that specimens with average measurements were not predominant in the studied population. This paper provides evidence of the presence of an aberrant form of P. lageniformis.


3) Luketa S. 2015. Morphological variability of two Quadrulella species (Arcellinida: Hyalospheniidae) from the Vlasina Lake region of Serbia. Biologia Serbica, 37(1-2): 22-30. PDF

Abstract: Here we present morphological and morphometrical data from sphagnicolous population of Quadrulella longicollis (Taranek) and both qualitative and quantitative characters of Q. symmetrica (Wallich) from the Vlasina Lake region (Serbia). Both broad and narrow types of Q. longicollis shells were observed, but intermediate forms were not noted. Subsequent data analysis supports the species status of Q. longicollis recently proposed in a molecular phylogenetic study. Based on 603 specimens, eight types of Q. symmetrica shells were observed: barrel-shaped shells, short broad shells without a pronounced neck, elongated pyriform shells, elongated square shells, short square shells, slightly curved shells, short broad shells with a pronounced neck and narrow shells. Intermediate forms between these types were also noted. Coefficients of variation were moderately low for all measured characters in the studied population. The minimal variability (4.5%) was observed for shell length, while maximal variability (9.35%) was recorded for the area of optical section. Analysis of the size frequency distribution suggests that Q. symmetrica is a size-monomorphic species.



4) Luketa S. 2016. Morphological variability of Porosia bigibbosa (Arcellinida: Hyalospheniidae) from East Herzegovina. Protistology, 10(4): 130-137. PDF

Abstract: The genus Porosia includes two species characterized by presence of two large invaginated pores. These pores are connected by internal tube as in members of the genus Certesella. In this paper, morphological variability of P. bigibbosa (Penard, 1890) Jung, 1942 based on 175 specimens from East Herzegovina is presented. Shell length ranges from 136 to 178 μm (previously noted 128-177 μm), shell width – from 86 to 118 μm (previously noted 83-123 μm), aperture width – from 40 to 51 μm (previously noted 34-49 μm), aperture-pore distance – from 45 to 62 μm (previously noted 52-70 μm), pore-pore distance – from 48 to 80 μm (previously not measured), and area of the optical section – from 9063 to 15706 μm2 (previously not measured). The minimal variability (4.5%) was observed for shell length, while maximal variability (9.01%) was recorded for the area of the optical section. Results of size frequency distribution analysis of shell length and shell width indicate that this population possesses continuous polymorphism.




5) Luketa S. 2016. First record of a size-trimorphic population among euglyphid testate amoebae. Protistology. 10(4): 138-147. PDF

Abstract: Morphology and morphometry of moss-dwelling population of Trinema penardi Thomas et Chardez, 1958 from the Island of Rab (Croatia) were investigated based on 196 specimens. Morphometric analysis showed that this population comprises three size-classes: small (shell length 58-61 µm, shell width 33-34 µm, aperture width 15-16 µm), medium (shell length 66-87 µm, shell width 36-51 µm, aperture width 17-24 µm), and large (shell length 87-105 µm, shell width 49-64 µm, aperture width 23-29 µm). Specimens with shell length between 30 and 65 µm (corresponding to small-size class) were reported earlier, whereas medium and large specimens were described for the first time in the present study. These data show that population of T. penardi from the Island of Rab can be considered as an example of very variable population characterized by discontinuous polymorphism.

6) Luketa S. 2017. Morphological variability of Nebela collaris s.s (Arcellinida: Hyalospheniidae) from Krečko Brdo Hill, East Herzegovina. Biologia Serbica. 39(2): 3-8. PDF

Abstract: Nebela collaris s.l. is the best studied species complex within the family Hyalospheniidae. This complex includes 11 taxa established on the basis of small differences in shell shape and size. The type species for this complex (N. collaris s.s.) was defined based on only four specimens. Here we present morphological and morphometric data from moss-dwelling population of N. collaris s.s. from Krečko Brdo Hill (East Herzegovina), based on 765 specimens. Shell length ranged from 87 to 115 μm (previously reported 95-115 μm), shell width from 53 to 73 μm (previously reported 74-81 μm) and aperture width from 21 to 31 μm (previously reported 28-32 μm). In the literature, reported shell length/shell width ratios range from 1.38 to 1.47, however subsequent morphometric analysis yielded values from 1.33 to 1.91. These data show that N. collaris s.s. can be considered to be a very variable pseudocryptic species among testate amoebae. Coefficients of variation were low for all measured characters in the studied population. Minimal variability (4.28%) was observed for shell length, while maximal variability (6.45%) was recorded for aperture width/shell length ratio. Analysis of the size frequency distribution suggests that the studied population of N. collaris s.s. is size-monomorphic.