identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
AB2A87A3FFBFFFF5FF03FD4A74EAFEC7.text	AB2A87A3FFBFFFF5FF03FD4A74EAFEC7.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Bythotrephes inexpectatus Korovchinsky 2023	<div><p>Bythotrephes inexpectatus sp. nov.</p> <p>(Figs. 1–2)</p> <p>Etymology. The name of the species denotes the surprise of its discovery in Austrian lakes of Central Europe.</p> <p>Type locality. <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=13.782778&amp;materialsCitation.latitude=47.609997" title="Search Plazi for locations around (long 13.782778/lat 47.609997)">Lake Altaussee</a>, Styria, Austria (47°36′36′′N; 13°46′58′′E), 712 m asl.</p> <p>Type material. Holotype. A female with body length 2.69 mm deposited in Zoological Museum of Moscow State University (№ MGU ML 262).</p> <p>Paratypes. Two females from the same sample deposited in the same museum (№ MGU ML 263). All other paratypes are deposited in author’s collection in the Institute of Ecology and Evolution.</p> <p>Material examined. Austria, Styria: 1) Lake Altaussee, 29.8.2012, 12 ad, 7 juv, coll. R. Ptáčniková; 2) Lake Toplitzsee, 29.8.2012, 9 ad, 4 males, 6 juv, coll. R. Ptáčniková. Data on body and body parts measurements of specimens are presented in Table 1.</p> <p>Description. Female. General body appearance and segmentation. Body elongated and divided into four parts: head, thorax, abdomen, and postabdomen with long caudal process (Figs. 1A, 1G). The longitudinal axis is conspicuously incurved when the head is located at almost right angle to the thorax. Highly movable abdomen can be either in a straight line with the thorax or stays at different angles to it. Head large with rounded anterior part filled by the enormously developed compound eye and bearing small antennules ventrally. Posterior part of head bears long swimming antennae and mouth parts consisting of mandibles, maxillules (mx I), and upper lip (labrum). Thorax with strongly developed muscular ventral side bearing four pairs of thoracic limbs of different sizes directed antero-ventrally. Dorsally, thorax bears a sack-like carapace transformed into a brood pouch, sometimes reaching large size. Abdomen (metasome) is elongated, cylindrical, inconspicuously three-segmented (see Korovchinsky 2015 for details) and flexible, connected with a small postabdomen, bearing ventrally a pair of claws and posteriorly a very long caudal process with a pair of similar claws proximally. General body length of females (without caudal process) may reach 2.8 mm or slightly more (in the examined specimens it ranges from 1.73 to 2.88 mm) while the length of caudal process may exceed the body length by 1.4–2.4 times (on average, about 1.8 times).</p> <p>Head. Comparatively very large (Fig. 1A) and subdivided into two parts: rounded anterior part mostly filled by large compound eye and posterior part bearing dorsally a large saddle-shaped neckorgan, swimming antennae and mouth parts. The large pigment spot occupies about one-third or at most half of the eye’s volume. Ocellus (naupliar eye) is absent.</p> <p>Antennules. Small and situated on the ventral side of the anterior head part beneath the eye. They are bulbous (Fig. 1B) and sit on the joined basis slightly split anteriorly. Terminally they bear five regular aesthetascs in two groups of two and three, and one shorter and thinner aesthetasc-like structure, situated in a group with two regular aesthetascs, and having slightly expanded apical end (“accessory simple seta” according to Scourfield (1896).</p> <p>Swimming antennae. Comparatively long, with elongated cylindrical basipodite (Fig. 1A). Of the two antennal branches, the lower three-segmented one, sitting on the apical basipodital prominence, is slightly longer than the upper branch. The upper branch (exopodite) is four-segmented and lower branch (endopodite) is three-segmented. Proximalmost segment of the upper branch is rudimentary and clearly visible only externally; all other segments of both branches are much more developed. Small spine with a row of neighboring minute prominences at the end of the distal segment of the superior antennal branch (Fig. 1F). Small proximalmost segment of upper branch lacks setae, while other segments possess two-segmented swimming setae of more or less similar size except distalmost of them which are shorter.All setae bilaterally armed with rows of uniform thin setules. General formula of antennal setae: 0‒1‒2‒5/1‒1‒5 (see Korovchinsky (2015) for more details).</p> <p>Mouth parts. They are represented by upper lip (labrum), mandibles, and maxillules (maxilla I). The upper lip is composed of two parts: the posterior thick and slightly flattened triangular lobe and anterior large proboscis-like outgrowth. Mandibles are bilobed and adapted for biting, with a toothed, blade-like posterior lobe and small anterior lobe (mandibular process). Posterior lobe is strongly sclerotized and divided in two tooth-shaped parts, the larger (posterior) of which has a small additional tooth about midway along its border. Maxillules (mx I) resemble two cylindrical structures situated posterior to the mandibles. Distally, they bear short central seta and some spinules near it. For details see description of mouth parts in other species of the genus which have the same structure (Korovchinsky 2015, 2018).</p> <p>Carapace. It resembles a bag-like structure, strongly modified into a closed brood pouch (Fig. 1A) widely connected in its base with the dorsal surface of the thorax. It may be often well developed and massive, when filled with large embryos.</p> <p>Thoracic limbs. Four pairs of strongly chitinized, stenopodous limbs, are densely situated along the muscular ventral side of thorax and directed antero-ventrally (Fig. 1A). All of them have complex and variously setaceous armament along their inner side. Limbs of the three anterior pairs are five-segmented, and those of the last fourth pair are three-segmented. Protopodites of all of them, covered by comparatively softer cuticle, are inconspicuously delimited into two parts (segments), coxa and basis, while the endopodites of limbs of the three anterior pairs are composed of three well developed segments and those ones of the fourth pair are single-segmented (Figs. 1C, 2A, 2B, 2C).</p> <p>First pair of limbs (tl I) are especially long and strong (Fig. 1C), though comparatively they are more or less short (63.8–92.6 %, av. 79.4% of body length). Terminally, the inner side of their protopodite bears a small triangular lobe, pseudognathobasic process (see the explanation of the term in Korovchinsky (2015)). The first segment of the endopodite is long and bears 5–6 anterior lateral setae with rows of spines and fine setules. Distally, this segment bears a shorter anterior seta of the same type and long posterior finely setulated seta (Figs. 1C, 1D). The second segment of the endopodite is conspicuously shorter and bears only two apical setae similar to those on the end of previous segment but shorter (Fig. 1E). The terminal third segment of the endopodite slightly varies in length, being shorter than the proximal first endopodital segment (72.2–95.4 %, av. 81% of the latter one) and always bearing apically four long roughly spinulated setae, two of them terminally and two subterminally.</p> <p>Second pair of limbs (tl II) are considerably shorter, their protopodite, again externally, is conspicuously longer and bears a conical outgrowth. The first basal segment of their endopodite bears a row of 5–7 rather long anterior lateral setae (their number can vary in one individual) (Fig. 2A: as). There are 1–2 posterior lateral setae (ps) on this segment. The terminal setae of the segment differ in that the anterior one is shorter and roughly armored, whereas the posterior one is longer and finely setulated. Internally, this segment bears a stout cylindrical pseudognathobasic process, possessing some prominences of different size and one small, thin seta (Fig. 2A). The second segment of the endopodite is short with only two setae, the anterior one of which is similar to the anterior terminal seta of previous segment, whereas the posterior seta is longer and finely setulated. The distal, third segment of endopodite of the limb bears four setae, two terminal and two subterminal ones (Fig. 2A).</p> <p>Third pair of limbs (tl III) are generally similar to those of the previous ones, differing in some details. The external outgrowth of their protopodite is conspicuously larger and lateral anterior and posterior setae (if present) of first segment of endopodite are fewer (4–5 and 1, respectively) (Fig. 2B). Distal setae of the segment are similar to other ones. The pseudognathobasic process is also similar to that of tl II. Of setae of the second segment, the anterior one is similar to the respective one of tl II. Terminal and subterminal setae of the third segment are similar to those of tl II but slightly shorter and bear fewer denticles.</p> <p>Fourth pair of limbs (tl IV) are considerably reduced (Fig. 2C); their protopodite bears slightly spinulated seta sited on a short cylindrical base. The only segment of the endopodite has two rows of comparatively short spine-like setae. The external row (group) (Fig. 2C: as) always consists of two setae, and the internal row of 6–7 setae, which differ in their appearance and armament. Almost the whole internal part of the endopodital segment is occupied by the reduced pseudognathobasic process, also armed by some denticles and thin seta.</p> <p>Abdomen (metasome) (Fig. 1A) is often deformed. It is inconspicuously delimited in two segments, short proximal and long distal with a prominent fold more or less in the middle dorsal side.</p> <p>“ Postabdomen” actually consists of two parts: the last small abdominal segment and the postabdomen per se (see Korovchinsky (2015) for more details), which is comparatively small, with the anal opening situated between the postabdominal claws. These claws are comparatively small (3.4–6.8 %, av. 4.7% of body length), more or less straight or slightly curved and directed slightly backwards (Figs. 2D–I).</p> <p>Caudal process is directly connected with the postabdomen and proceeds as a very long, proximally rather thick and curved, then straight spine-like structure (Figs. 1A, 1G), variable in its length (138.0–239.0 %, av. 184% of body length), thus exceeding the body length by about 1.4-2.4 times. Generally, the caudal process is strongly chitinized and its surface covered by numerous minute spinules. Basally, the caudal process bears one pair of claws similar to those of the postabdomen but usually larger (4.0–8.5%, av. 5.9% of body length), and apically two minute setae arise from a common base (Fig. 1H). Pairs of claws of postabdomen and caudal process sit closely, interclaw distance usually constitutes 5.8–8.4% (av. 7.0%). Between the claws, the thickness of the structure constitutes 4.4–7.9 % (av. 6.0%). Borders separating old molted integuments of caudal process with claws always are quite conspicuous.</p> <p>Gamogenetic females have not been detected.</p> <p>Males. The thoracic limbs of the first pair (tl I) are comparatively short (59.0–73.0 % of body length) as well as each segment of them, especially the distal one, which is slightly swollen proximally and bears on its inner side a small strongly chitinized hook with two inner denticles (Figs. 1I, 1J). The copulatory appendages are small and armed with numerous minute spinules terminally (Fig. 1K).</p> <p>Size. Adult females— 1.73–2.88 mm. in length. Males, on average, are smaller than females (body length— 1.86–2.08 mm.).</p> <p>Intrapopulation variability of females. According to Table 1, the length of claws of the postabdomen and caudal process is especially variable (CV = 21.3–22.5, respectively), the interclaw distance and interclaw thickness follow them in this respect (CV = 11.3–11.8). At the same time, the claw shape is more or less stable. Of other structures, the comparative length of thoracic limbs of the first pair (tl I) seems also rather variable (CV = 8.4).</p> <p>Differential diagnosis. Bythotrephes inexpectatus sp. nov. is close to B. longimanus s.l. and B. centralasiaticus Korovchinsky, 2020 in having, in adult specimens, only one pair of claws on caudal process. At the same time, it differs from the former species (Table 2) in a unique combination of morphological features: relatively smaller body length; presence of very closely situated pairs of claws, the borders of which separating old molted integument always are quite conspicuous; presence of shorter thoracic limbs of first pair (tl I) and shorter caudal process (for all parameters p &lt;0.001). Also, tl I of the new species bears long seta (vs. short or rudimental in B. longimanus s.l.) at the apical end of the second endopodital segment of tl I. Compared to B. centralasiaticus, the specimens of Bythotrephes inexpectatus sp. nov. have on average larger body length, shorter caudal process, smaller claws of the postabdomen and caudal process, larger thickness of caudal process between pairs of claws, and conspicuously smaller interclaw distance (for all parameters p &lt;0.001).</p> <p>The adult females of all other species of the genus Bythotrephes and those of widely distributed interspecies hybrids B. brevimanus x B. cederströmii possess one-two pairs of claws on caudal process. Besides that, the relatively closely distributed B. brevimanus s.str., possesses, compared to the new species, smaller claws of postabdomen and caudal process that sit more distant from each other (p &lt;0.001).</p> <p>Geographical distribution. So far, representatives of a new species are known to occur only in two deep subalpine lakes in the central part of Austria.</p></div> 	https://treatment.plazi.org/id/AB2A87A3FFBFFFF5FF03FD4A74EAFEC7	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Korovchinsky, Nikolai M.	Korovchinsky, Nikolai M. (2023): Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa. Zootaxa 5264 (1): 77-93, DOI: 10.11646/zootaxa.5264.1.5, URL: http://dx.doi.org/10.11646/zootaxa.5264.1.5
AB2A87A3FFBAFFF5FF03FE7374FCFD52.text	AB2A87A3FFBAFFF5FF03FE7374FCFD52.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Bythotrephes longimanus Leydig 1860	<div><p>Bythotrephes longimanus Leydig, 1860</p> <p>This is the type species of the genus which was thoroughly revised by Korovchinsky (2015), when its representatives from the type locality (Lake Bodensee) and from some localities of Switzerland, Austria, Italy, and Great Britain were investigated. The Austrian representatives of the species were only slightly affected by this study. The present investigation using more abundant material has revealed that the latter ones are really morphologically specific, differing from specimens of western populations, and therefore worthy of being allocated to a separate taxon. Therefore, it turns out that the species B. longimanus is represented by two subspecies, B. longimanus longimanus Leydig and another new one described below.</p> </div>	https://treatment.plazi.org/id/AB2A87A3FFBAFFF5FF03FE7374FCFD52	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Korovchinsky, Nikolai M.	Korovchinsky, Nikolai M. (2023): Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa. Zootaxa 5264 (1): 77-93, DOI: 10.11646/zootaxa.5264.1.5, URL: http://dx.doi.org/10.11646/zootaxa.5264.1.5
AB2A87A3FFBAFFF5FF03FC8775CEFBFB.text	AB2A87A3FFBAFFF5FF03FC8775CEFBFB.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Bythotrephes longimanus subsp. longimanus Leydig 1860	<div><p>Bythotrephes longimanus longimanus Leydig, 1860</p> <p>The detailed redescription of the taxon with the designation of a neotype has been done by Korovchinsky (2015).</p> <p>The specimens of nominotypical subspecies have generally larger body size (up to 3.06 mm) but their most pronounced diagnostic difference is the presence of large, directed more or less down, claws of postabdomen (6.6– 14.0% of body length) and caudal process (6.0–15% of body length) (Table 2).</p> <p>Geographical distribution. Deep subalpine lakes of Switzerland, Southern Germany, and Northern Italy. The occurrence of the taxon in Great Britain requires further confirmation.</p></div> 	https://treatment.plazi.org/id/AB2A87A3FFBAFFF5FF03FC8775CEFBFB	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Korovchinsky, Nikolai M.	Korovchinsky, Nikolai M. (2023): Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa. Zootaxa 5264 (1): 77-93, DOI: 10.11646/zootaxa.5264.1.5, URL: http://dx.doi.org/10.11646/zootaxa.5264.1.5
AB2A87A3FFBAFFF8FF03FB6F74EAFAAF.text	AB2A87A3FFBAFFF8FF03FB6F74EAFAAF.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Bythotrephes longimanus subsp. austriacus Korovchinsky 2023	<div><p>Bythotrephes longimanus austriacus ssp. nov.</p> <p>(Figs. 3, 4)</p> <p>B. longimanus Leydig: Steuer, 1897: p. 520 (Lake Millstättersee).</p> <p>B. longimanus v. carnica Ischreyt, 1939: 125–126, 128, Abb. 6.</p> <p>B. longimanus longimanus Leydig, 1860: Flössner, 1972: 405–406, Abb. 190A; 2000: 375</p> <p>B. longimanus Leydig, 1960: Korovchinsky, 2015: 20, Figs. 8E, 8F, 8I, 8K, 8P, 8Q, 8R, 8X.</p> <p>Etymology. The name of the species denotes the occurrence of the taxon in Austrian subalpine lakes.</p> <p>Type locality. <a href="https://tb.plazi.org/GgServer/search?materialsCitation.longitude=15.295279&amp;materialsCitation.latitude=47.814167" title="Search Plazi for locations around (long 15.295279/lat 47.814167)">Lake Erlaufsee</a>, Styria, Austria (47°48′51′′N; 15°17′43′′E), 827 m a.s.l.</p> <p>Holotype. A female with body length 2.08 mm deposited in Zoological Museum of Moscow State University (№ MGU Ml 264).</p> <p>Paratypes. Three females from the same sample deposited in the same museum (№ MGU Ml 265).</p> <p>Material examined. Austria: 1) Lake Erlaufsee (Styria), 18.9.2018, 20 ad, 5 juv, coll. R. Ptáčniková; 2) Lake Irrsee (Upper Austria), 27.8.2012, 7 ad, coll. R. Ptáčniková; 3) Lake Wolfgangsee (Upper Austria), 28.8.2012, 9 ad, coll. R. Ptáčniková; 4) Lake Grundlsee (Styria), 18.7.2007, 20 ad, leg. M. Luger; 5) Lake Millstättersee (Carinthia), 8.11.2011, 2 ad, 1 male, 1 juv. leg. G. Santner; 6) Lake Mondsee (Upper Austria), 7.1993, 5 ad, leg. H. Löffler and S. Gaviria-Melo. (specimens from the localities 4-6 were investigated earlier (see Korovchinsky 2015) but here after adding new individuals their diagnostic features were revised anew).</p> <p>Data on body and body parts measurements of specimens from Erlaufsee and Grundlsee are presented in Table 1 (see also Korovchinsky 2015: Table 2).</p> <p>Description. Female. The general body structure and its parts as in other representatives of the genus.</p> <p>Thoracic limbs: four pairs (Figs. 2, 3)</p> <p>First pair of limbs (tl I) are especially long and strong (Fig. 3A) (78.9–129.6 % of body length). The first segment of the endopodite is long and bears 4–8 (mostly 5–8) anterior lateral setae with rows of spines and fine setules. Distally, this segment bears shorter anterior seta of the same type and long posterior finely setulated seta (Figs. 3B–E). The second segment of the endopodite is conspicuously shorter and bears only two apical either short or rudimentary setae (Fig. 3F–R). The terminal third segment of the endopodite slightly varies in length, being either shorter or slightly longer than the proximal first endopodital segment (71.4–108.0 % of body length) and always bearing apically four long roughly spinulated setae, two of them terminally and two subterminally.</p> <p>Second pair of limbs (tl II) are considerably shorter, their protopodite, again externally, is conspicuously longer and bears a conical outgrowth. The first basal segment of their endopodite bears a row of 4–8 (mostly 5–8) rather long anterior lateral setae (their number can vary in one individual). There are 1–3 posterior lateral setae on this segment. Internally, this segment bears a stout cylindrical pseudognathobasic process, possessing some prominences of different size and one small, thin seta. The second segment of the endopodite is short with only two setae, the anterior one of which is similar to the anterior terminal seta of previous segment, whereas the posterior seta is longer and finely setulated. The distal, third segment of endopodite of the limb bears four setae, two terminal and two subterminal ones.</p> <p>Third pair of limbs (tl III) are generally similar to those of the previous ones, differing in some details. The external outgrowth of their protopodite is conspicuously larger and lateral anterior and posterior setae (if present) of first segment of endopodite are fewer (4–6 and 1–2, respectively). The pseudognathobasic process is also similar to that of tl II. Terminal and subterminal setae of the third segment are similar to those of tl II but slightly shorter and bear fewer denticles.</p> <p>Fourth pair of limbs (tl IV) are considerably reduced; their protopodite bears slightly spinulated seta sited on a short cylindrical base. The only segment of the endopodite has two rows of comparatively short spine-like setae. The external row (group) (Fig. 2C: as) always consists of two setae, and the internal row of 5–8 (mostly 6–7) setae, which differ in their appearance and armament.</p> <p>The “ postabdomen” actually consists of two parts: the last small abdominal segment and the postabdomen per se (see Korovchinsky (2015) for more details), which is comparatively small, with the anal opening situated between the postabdominal claws. These claws are comparatively small (2.9–7.8 % of body length) and clearly directed backwards (Fig. 4A–H).</p> <p>Caudal process is directly connected with the postabdomen and proceeds as a very long, proximally rather thick and curved, then straight spine-like structure, variable in its length (159.0–274.0 % of body length), thus exceeding the body length by about 1.6–2.7 times. Basally, the caudal process bears one pair of claws similar to those of the postabdomen but usually larger (3.8–9.5% of body length). Pairs of claws sit moderately distantly, interclaw distance usually constitutes 8.1–22.9%. Between the claws, the thickness of the structure constitutes 4.1–9.6 %. Borders separating old molted integuments of caudal process with claws either are conspicuous or invisible.</p> <p>Size. 1.41–2.42 mm.</p> <p>Gamogenetic females have not been detected.</p> <p>Males. The only male we found did not differ, as usual, from males of the nominotypical subspecies.</p> <p>Intrapopulation variability. According to Table 1, the length of claws of postabdomen and caudal process is especially variable (CV = 12.7–21.2 and 14.4–18.7, respectively), the interclaw distance and interclaw thickness follow them in this respect (CV = 13.1–14.4 and 11.5–16.5, respectively). Of other structures, the comparative length of thoracic limbs of the first pair and that of caudal process are also rather variable (CV = 6.9–7.2 and 9.9–12.9, respectively). Also, the apical setae armament of a second endopodital segment of tl I (Fig. 3) and shape of claws of postabdomen and caudal process (Fig. 4) are variable as well.</p> <p>Differential diagnosis. The representatives of Bythotrephes longimanus austriacus ssp. nov. have generally a relatively smaller body size (up to 2.42 mm vs. 3.1 mm in B. longimanus longimanus) but they mostly differ from those of the B. l. longimanus by relatively smaller claws of postabdomen and caudal process (Table 2) (p &lt;0.001) which both are directed backwards, not downwards as in the nominotypical subspecies.</p> <p>Remarks. The present study confirmed the past preliminary observation that “Small size of claws of postabdomen and caudal process was the most pronounced common feature of all Austrian specimens” of B. longimanus (Korovchinsky 2015: p. 20).</p> <p>B. longimanus v. carnica was described by Ischreyt (1939) from Lake Millstättersee (Carinthia) with indication of doubtful diagnostic features, why a taxon can be considered incertae sedis (ICZN 67.2.5). Morphological traits of specimens from this lake certainly do not differ from those of B. l. austriacus occurring in some other adjacent lakes.</p> <p>Geographical distribution. T he representatives of the new subspecies are known to occur in some deep subalpine lakes in the central part of Austria.</p></div> 	https://treatment.plazi.org/id/AB2A87A3FFBAFFF8FF03FB6F74EAFAAF	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Korovchinsky, Nikolai M.	Korovchinsky, Nikolai M. (2023): Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa. Zootaxa 5264 (1): 77-93, DOI: 10.11646/zootaxa.5264.1.5, URL: http://dx.doi.org/10.11646/zootaxa.5264.1.5
AB2A87A3FFB6FFF9FF03FF52746BF80B.text	AB2A87A3FFB6FFF9FF03FF52746BF80B.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Bythotrephes brevimanus Lilljeborg 1901	<div><p>Bythotrephes cf. brevimanus Lilljeborg, 1901</p> <p>(Fig. 5A–C, G–I)</p> <p>B. styriacus Ischreyt, 1939: 126–128, Abb. 7.</p> <p>B. longimanus longimanus Leydig, 1860: Flössner, 1972: 405–406.</p> <p>B. longimanus styriacus Ischreyt, 1939: Flössner, 2000: 375–376.</p> <p>Material examined. Austria (Upper Austria): Halstättersee, 29.8.2012, 10 ad, 7 juv., coll. R. Ptáčniková.</p> <p>Data on body and body parts measurements are presented in Table 1.</p> <p>Description. Female. The general body structure and its parts as in other representatives of the genus.</p> <p>Thoracic limbs of first pair (tl I) are especially long and strong, their length often surpasses body length (93.7–114.8 %, av. 104.7% of its length) (Table 1). The first segment of endopodite is long and bears 5–6 anterior lateral setae (their number on limbs of one individual can vary) with a posterior row of rough incurved spines and anterior and lateral rows of fine setules. Distally, this segment bears shorter anterior seta of the same type and long posterior finely setulated seta (Fig. 5A). The second segment of endopodite is conspicuously shorter and bears only two apical shorter setae similar to those on the end of previous segment (Fig. 5B, 5C). The terminal third segment of endopodite is shorter than proximal first endopodital segment (81.1–95.6% of the latter one) and always bears apically four long roughly spinulated setae, two of them terminally and two subterminally.</p> <p>The structure and armament of limbs of the second-fourth pairs as in the representatives of the species described earlier (see Korovchinsky, 2018).</p> <p>The “ postabdomen” is actually consisting, as usual, of two parts—the last small abdominal segment and postabdomen per se (see Korovchinsky (2015) for more details), is comparatively small, The postabdominal claws are comparatively small (2.5–4.8% of body length), may be directed either almost down or backwards, sometimes with apex curved slightly forward (Figs. 5G–I).</p> <p>Caudal process is directly connected with postabdomen and proceeds as a very long, proximally rather thick and curved, then straight spine-like structure variable in its length (180–248 % of body length), thus surpassing the body length in 1.8–2.5 times. Basally, caudal process bears one or two pairs of claws similar to those of postabdomen but usually larger (e.g., proximal claws reach 3.2–6.4 % and distal ones 4.1–6.3% of body length, respectively). Pairs of claws sit more or less closely (distance between postabdominal claws and proximal claws of caudal process (interclaw distance) usually constitutes 9.3–19.2 % of body length). Between the latter, the thickness of the structure constitutes 5.1–7.2% of body length. Borders separating old molted integuments of caudal process with claws are moderately conspicuous.</p> <p>Size. Body length 1.66–2.53 mm.</p> <p>Gamogenetic females and males have not been detected.</p> <p>Interpopulation variability. Despite the presence of a small set of Austrian specimens (adult females) of the species (n =10), it is possible to make some comparisons with those of B. brevimanus previously studied (Korovchinsky (2018). The specimens from Lake Halstättersee are comparatively larger, having unusually long thoracic limbs of the first pair (tl I) with rather long endopodital distal segment which, however, is always shorter than proximal one. Then, their postabdominal claws are smaller and all their pairs sit more densely than in most other studied populations of the species. Also, the interclaw thickness is larger and borders separating old molted integument of caudal process with claws are less noticeable than usual.</p> <p>Remarks. Ischreyt (1936, 1937) suggested the specificity of the representatives of Bythotrephes from Lake Halstättersee and soon later described them as new species B. styriacus (Ischreyt 1939) but without real evidence presenting doubtful diagnostic traits. Moreover, he considered this species occurring in some other adjacent lakes (Wolfgangsee, Mondsee, Grundlsee, Altaussee) where other taxa, B. inexpectatus sp. nov. and B. l. austriacus ssp. nov., occur, which makes the situation more confusing.</p> <p>Generally, Ischreyt brings his new species closer to B. brevimanus (= B. balticus Ischreyt) but noted the comparatively larger body size of its specimens which matches the data of the present study. Based on the above described morphological specificities of studied specimens and their unusual for B. brevimanus occurrence in mountain lake it is possible to suspect that they really represent a separate taxon, but this statement requires additional material and evidence.</p> </div>	https://treatment.plazi.org/id/AB2A87A3FFB6FFF9FF03FF52746BF80B	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Korovchinsky, Nikolai M.	Korovchinsky, Nikolai M. (2023): Unexpected high species richness of Bythotrephes Leydig, 1860 (Branchiopoda: Cladocera: Cercopagididae) in subalpine Austrian lakes, with the description of new taxa. Zootaxa 5264 (1): 77-93, DOI: 10.11646/zootaxa.5264.1.5, URL: http://dx.doi.org/10.11646/zootaxa.5264.1.5
