taxonID	type	description	language	source
AF67AD40F75EFFD30DFF89B7B3AAFAEA.taxon	description	Ephippial females producing ephippia of the vetulus type (Figs. 5 A – G, 6 A – C) have a uniform morphology, but the shape of the ephippia is somewhat different due to differences in the anteroventral edge. This edge is formed by relatively fragile valve tissue which is not preserved in recent (Figs. 7 A – C) and fossil ephippia (see below). The ephippium anteroventral edge in gamogenetic female may be broadly rounded (Figs. 5 A, C, F) or more or less protruding (Figs. 5 B, D, 6 A, C). This feature requires further analysis, but it may have taxonomic value for distinguishing between congeneric taxa within this morphotype. Recent ephippia of the vetulus - type reach 1.04 mm in length and 0.66 mm in height. The smallest ephippium is found in the Republic of Yakutia; its length is only 0.48 mm. The shape of the ephippium is subtriangular (Figs. 5 A – G, 6 A – C, 7 A – C, 8 A – I, 9 A – H, 10 A – H, 11 A – C, 12 A – I, 13 A – C, 14 A – I, 15 A – I, 16 A – C). Posteroventral edge is broadly rounded, anterodorsal edge is acute. Dorsal edge is straight or concave. The single ovarian locule is ovoid in shape and does not rise significantly above the surface of the ephippium. The longitudinal axis of the egg is located almost parallel to the dorsal margin or turned towards it. Ephippium ornamentation in the central portion of the egg locule is represented by hillocks of moderate height, with prominent processes. In most cases, these hillocks have a polygonal shape, but some hillocks may be rounded or almost rounded (Figs. 2 A – I, 3 A – E). No obvious differences in the sculpture are found in the populations from different climatic zones. Ephippia belonging to the vetulus - type are found in our material only in Eurasia (Fig. 1), but they may be discovered in other continents, taking into account recent ideas on the distribution pattern of the S. vetulus species complex (Kotov 2013).	en	Varakina, Elizaveta D., Neretina, Anna N., Tumskaya, Vasilisa V., Boeskorov, Gennadiy G., Kotov, Alexey A. (2026): Morphological conservatism and variability in the ephippium sculpture of the genus Simocephalus Schoedler, 1858 (Crustacea: Cladocera: Daphniidae). Zootaxa 5741 (2): 201-251, DOI: 10.11646/zootaxa.5741.2.1, URL: https://doi.org/10.11646/zootaxa.5741.2.1
AF67AD40F75AFFD30DFF89FCB14EF84E.taxon	description	Females producing epiphippia of the vetuloides-mixtus type are identical in the three populations studied. Unlike the vetulus - type, the anteroventral edge of the ephippium in gamogenetic females is noticeably protruding (Figs. 17 A – B). Recent ephippia of vetuloides-mixtus - type reach 0.85 mm in length and 0.48 mm in height. The smallest ephippium is found in the Republic of Yakutia, its length is only 0.65 mm. Ephippium shape is subtriangular, elongated (Figs. 17 A – B, 18 A – I). Posteroventral edge of ephippium is rounded, anterodorsal edge is acute. Dorsal edge is straight, concave or convex. The single ovarian locule is ovoid in shape and moderately elevated above the ephippium surface. The longitudinal axis of the egg is almost parallel to the dorsal margin or turned towards it. Ephippium ornamentation in the central portion of egg locule is represented by rounded hillocks with processes strongly protruding above the ephippium surface. In most cases hillocks possess prominent processes, but sometimes their tips may be rounded (Figs. 3 F – I). This morphotype is found only in the Asian part of Russia and has a more local distribution as compared to other morphotypes (Fig. 1). Since the type locality of S. vetuloides is located in Yakutia, this taxon may be the first candidate for a detailed taxonomic revision and full redescription.	en	Varakina, Elizaveta D., Neretina, Anna N., Tumskaya, Vasilisa V., Boeskorov, Gennadiy G., Kotov, Alexey A. (2026): Morphological conservatism and variability in the ephippium sculpture of the genus Simocephalus Schoedler, 1858 (Crustacea: Cladocera: Daphniidae). Zootaxa 5741 (2): 201-251, DOI: 10.11646/zootaxa.5741.2.1, URL: https://doi.org/10.11646/zootaxa.5741.2.1
AF67AD40F758FFD10DFF885BB32BF885.taxon	description	Ephippial females producing ephippia of the serrulatus - type are almost identical morphologically in all investigated populations (Figs. 19 A – G, 20 A – C), but denticles on the head of S. serrulatus from the Republic of Khakassia (Figs. 20 B – C) are more developed as compared to the populations from Ontario Province and Nizhny Novgorod Area (Figs. 19 B – C, E, G). Remarkably, the characteristic acute anteroventral angle is evident in parthenogenetic females (Fig. 19 F), but it is almost absent in ephippial females (Figs. 19 A, D, 20 A). In contrast to previous morphotypes, the anteroventral and posteroventral edge of the ephippium is almost equal in height and form a fringe (Figs. 19 A, D, 20 A). Recent ephippia of the serrulatus - type reach 1.08 mm in length and 0.65 mm in height. The smallest ephippium is found in Ontario Province, its length is only 0.66 mm. The shape of ephippium is subtriangular (Figs. 17 A – B, 18 A – I). Posteroventral edge of ephippium is rounded, anterodorsal edge is acute. Dorsal edge is straight, concave or convex. A sole egg locule has an ovoid shape and is moderately elevated above the ephippium surface. Longitudinal egg axis is turned towards the ephippium dorsal margin. Ephippium ornamentation in the central portion of the egg locule is represented by rounded hillocks of moderate height, almost lacking processes, or bearing completely flat hillocks without processes, or with some minor processes (Figs. 4 A – F). We found rectangular flat hillocks in a single largest ephippium from Central Bohemian Region, but in the same sample specimens with smaller rounded hillocks are also present (Figs. 4 D – F). This morphotype is found both in Eurasia and North America (Fig. 1). We can confirm preliminary genetic data on a close relationship between the serrulatus - like populations from Eastern Palearctic and North America (Huang et al. 2014).	en	Varakina, Elizaveta D., Neretina, Anna N., Tumskaya, Vasilisa V., Boeskorov, Gennadiy G., Kotov, Alexey A. (2026): Morphological conservatism and variability in the ephippium sculpture of the genus Simocephalus Schoedler, 1858 (Crustacea: Cladocera: Daphniidae). Zootaxa 5741 (2): 201-251, DOI: 10.11646/zootaxa.5741.2.1, URL: https://doi.org/10.11646/zootaxa.5741.2.1
AF67AD40F742FFC90DFF8AF1B675FAFA.taxon	description	Fossil ephippia of the vetulus - type reach 1.52 mm in length and 0.85 mm in height. The smallest ephippium is found in Arkhangelsk Area, its length is only 0.76 mm. The shape of the ephippium is subtriangular (Figs. 24 A – C, 25 A – C, 26 A – C, 27 A – D, 28 A – D, 29 A – F, 30 A – B, 31 A – B). Posteroventral edge is broadly rounded, anterodorsal edge is acute. Dorsal edge is straight or concave. A sole egg locule has an ovoid shape and not significantly elevated above the ephippium surface. Longitudinal egg axis is almost parallel to the dorsal margin or turned towards it. Ephippium ornamentation in the central portion of egg locule is represented by hillocks of moderate height with prominent processes (Figs. 23 A – D). In most cases hillocks are of polygonal shape. Fossil ephippia belonging to the vetulus - type are found in Eurasia (Arkhangelsk Area; Yana Rhinoceros Horn Site, Republic of Yakutia) and North America (Tom Creek, Yukon; River Titaluk, Alaska) (Fig. 1). According to published photos of Simocephalus ephippia from the sediments of Titaluk Rivers (Kuzmina et al. 2019: figs. 9 c – d), they also belong to the vetulus morphotype due to presence of prominent processes.	en	Varakina, Elizaveta D., Neretina, Anna N., Tumskaya, Vasilisa V., Boeskorov, Gennadiy G., Kotov, Alexey A. (2026): Morphological conservatism and variability in the ephippium sculpture of the genus Simocephalus Schoedler, 1858 (Crustacea: Cladocera: Daphniidae). Zootaxa 5741 (2): 201-251, DOI: 10.11646/zootaxa.5741.2.1, URL: https://doi.org/10.11646/zootaxa.5741.2.1
AF67AD40F740FFC90DFF898CB194F85E.taxon	description	Fossil ephippia of the serrulatus - type reach 1.17 mm in length and 0.66 mm in height. The smallest specimen is found at the Yana rhinoceros horn site (Republic of Yakutia), its length is only 0.72 mm. The shape of the ephippia is subtriangular (Figs. 32 A – H, 33 A – F, 34 A – B). Posteroventral edge is rounded, anterodorsal edge is acute, sometimes attenuated. Dorsal edge is straight, concave or convex. The single egg locule is ovoid in shape and is moderately elevated above the surface of the ephippium. The longitudinal axis of the egg is oriented towards the dorsal margin of the ephippium or almost parallel to it. Ephippium ornamentation in the central portion of egg locule is represented by rounded hillocks of moderate height, without processes or completely flat. Sometimes the ephippium surface is smooth or worn out, but the border between cells is visible. This morphotype is found both in Eurasia (Arkhangelsk Area; Perm Krai; Yana Rhinoceros Horn Site, Chukochya River, the Republic of Yakutia; Bely Yar, the Republic of Buryatia) and North America (Old Crow, Yukon) (Fig. 1). Ephippia of Simocephalus from the sediments of the Old Crow River (Kotov et al. 2019: figs. 3 e – h), Bely Yar II section (Kuzmina et al. 2021: figs. 4 f – h), the Bol’shaya Chukochya River valley (Kirillova et al. 2016: figs. 7 g – h) belong to the same morphotype due to a lack of prominent processes.	en	Varakina, Elizaveta D., Neretina, Anna N., Tumskaya, Vasilisa V., Boeskorov, Gennadiy G., Kotov, Alexey A. (2026): Morphological conservatism and variability in the ephippium sculpture of the genus Simocephalus Schoedler, 1858 (Crustacea: Cladocera: Daphniidae). Zootaxa 5741 (2): 201-251, DOI: 10.11646/zootaxa.5741.2.1, URL: https://doi.org/10.11646/zootaxa.5741.2.1
AF67AD40F741FFC80DFF8A8AB304F83D.taxon	description	Despite significant efforts, we found only a single ephippium belonging to this type of sculpture. Its length is 0.88 mm and its height is 0.57 mm. General shape of the ephippium is typical of the genus Simocephalus. The ornamentation pattern is characterized by small, scattered hillocks that do not protrude above the ephippium surface (Figs. 35 A – B). We did not find this type of ornamentation in any recent populations. It probably belongs to an extinct taxon.	en	Varakina, Elizaveta D., Neretina, Anna N., Tumskaya, Vasilisa V., Boeskorov, Gennadiy G., Kotov, Alexey A. (2026): Morphological conservatism and variability in the ephippium sculpture of the genus Simocephalus Schoedler, 1858 (Crustacea: Cladocera: Daphniidae). Zootaxa 5741 (2): 201-251, DOI: 10.11646/zootaxa.5741.2.1, URL: https://doi.org/10.11646/zootaxa.5741.2.1
