Leydigia (Neoleydigia) iberica, Kotov & Alonso, 2010
Kotov, Alexey A. & Alonso, Miguel, 2010, Two new species of Leydigia Kurz, 1875 (Chydoridae, Cladocera) from Spain, Zootaxa 2673 (1), pp. 39-55 : 40-45
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|Leydigia (Neoleydigia) iberica|
Leydigia (Neoleydigia) iberica sp. nov.
( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 )
Leydigia acanthocercoides . — Alonso 1996: 361–363, figs. 161–162. [Non Fischer, 1854].
Leydigia (Neoleydigia) sp. nov. — Kotov 2009: 42–43.
Etymology. The species name refers to the Iberian Peninsula, where this animal was found.
Type locality. Laguna Longuilla , Fuentes de Andalucía, Sevilla, Spain (37º28’33”N; 5º21’57”W). Date of collection: April 1979 GoogleMaps .
Type material. Holotype. Undissected parthenogenetic female preserved with 4% formaldehyde in a vial deposited in the MNCN (accession number: 20.04/8553).
Paratypes. Five parthenogenetic females preserved with 4% formaldehyde in a vial deposited in the MNCN (accession number: 20.04/8554) .
Diagnosis. Parthenogenetic female. Body subovoid, postero-dorsal angle well-defined. Coarse striation on valves absent, a fine striation well-expressed. Head small, compound eye and ocellus subequal in size. PP = 7–8 IP, lateral head pores about 0.6 IP distance from midline. Labral keel subtriangular, its anterior margin with long fringe of setules up to apex; 4 or 5 lateral groups of relatively long and strong setules on sides of keel plus several series of short, fine setules. In middle of ventral margin, short setules between bases of setae. Submarginal setules of whole posterior margin fine. Marginal membrane (see terminology in Kotov 2009) absent. Postabdomen subovoid, preanal margin equal to or somewhat shorter than anus, with numerous small hillocks, preanal and postanal angles well defined, neither distal margin nor dorso-distal angle on postabdomen. Postanal marginal denticles in about 20–24 clusters, about 10 fascicles of stout lateral setae, 3 or 4 per fascicle. About 19–22 fascicles of lateral setules on basal half of postanal and anal margin. Postabdominal claw without a basal spine.
Antenna I not reaching tip of rostrum, with 4 transverse rows of long setules on anterior face, stout setules at its end; sensory seta arising at distance of 1/5–1/6 of appendage length from distal end. Largest aesthetasc about half as long as appendage, reaching tip of rostrum. Antenna II with 4 stout spine-like setules on first and on second endopod segments. Trunk limb I with ODL seta with unilaterally setulated distal segment; IDL with three marginal clusters of long setules and three bisegmented setae; different in size but similar in setulation, on limb corm seta 1 long, seta 2 short, seta 3 rudimentary. On trunk limb II, distalmost scraper with unilaterally setulated basal segment, on distal lobe with basal tuft of long setules. Trunk limb III exopodite trapezium-shaped, with five setae; distal segment of seta 2 with alternation of short and long setules, seta 3 short, in filter plate seven setae, basalmost and distalmost setae shorter than rest; filter plate III with seven setae. Trunk limb IV with subovoid exopodite bearing six setae, seta 1 shortest. Inner face of limb V, two setulated setae of unequal length, distal armature of gnathobase a setulated lobe, 'filter plate' with two small setae.
Ephippium. Slightly chitinized, brown.
Adult male. Unknown.
Size. Parthenogenetic female up to 1.15 mm.
Description. Parthenogenetic female. General. In lateral view body subovoid, maximum height in middle ( Fig. 1A View FIGURE 1 ). Dorsal margin slightly convex in posterior part, postero-dorsal angle well-defined. Posteroventral angle completely rounded; ventral margin regularly convex. Coarse striation on valves absent, valves with a very obscure polygonal reticulation, a well-expressed fine striation present within the reticulation cells.
Head relatively small, triangle-round in lateral view, with short, blunt, downward pointing rostrum ( Fig. 1B View FIGURE 1 ). Compound eye and ocellus subequal in size, distance from tip of rostrum to ocellus significantly more than that between ocellus and eye.
Head shield wide, covered by fine striation, in posterior portion three closely located major head pores of subequal size, with connection between them, PP = 7–8 IP ( Fig. 1C–D View FIGURE 1 ). Lateral head pores about 0.6 IP distance from midline, at level of central major head pore, all head pores located on a plate without striation ( Fig. 1E View FIGURE 1 ).
Labrum with large medial labral keel, widely-triangular-ovoid, with well-defined apex ( Fig. 1B, F View FIGURE 1 ). Posterior margin straight, with tufts of middle-sized setules, anterior margin regularly convex, with fringe of long setules from base to apex; on sides of keel there are 4-5 lateral groups of long and strong setules, longer than longest marginal setules, plus several series of short, fine setules.
Valves large, subovoid, with numerous setae on ventral margin, longest in posterior half ( Fig. 1G View FIGURE 1 ). In middle of margin bases located slightly submarginally, short setules between them (fig. 1H). Posteriorly to the last marginal seta, a row of submarginal setules starts on inner valve face of valve posterior margin, basally they are organized into groups. Marginal membrane absent.
Thorax relatively long. Abdomen short, distal edges of segments with transverse rows of setules, basal abdominal segment with a distinct abdominal projection ( Fig. 1A View FIGURE 1 ).
Postabdomen subovoid, robust, with maximum height in middle ( Fig. 2A View FIGURE 2 ). Ventral margin slightly convex, with rows of minute setules. Preanal margin equal to or somewhat shorter than anus, with numerous small hillocks, preanal and postanal angles well defined, while distal margin and dorso-distal angle of postabdomen ot expressed. Postanal marginal denticles in about 20–24 clusters, 4 series of marginal setules on anal margin. On postanal margin, about 9 or 10 fascicles of stout lateral setae, 3 or 4 setae in each fascicle on distal portion, two marginalmost setae of each fascicle subequal in size, other setae much shorter ( Fig. 2B View FIGURE 2 ). About 19–22 fascicles of lateral setules on basal half of postanal and anal margin ( Fig. 2C View FIGURE 2 ).
Postabdominal seta about two times longer than anal plus preanal margin; its distal segment somewhat shorter than basal one.
Postabdominal claw robust, almost straight, longer than preanal plus anal portion of postabdomen. On lateral side, two successive series of slender setules along the dorsal margin. Basal spine fully absent.
Antenna I not reaching tip of rostrum, with 4 transverse rows of long setules on anterior face, stout setules at its end ( Fig. 2E View FIGURE 2 ). Sensory seta particularly long, slender, arising at distance of 1/5–1/6 of appendage length from distal end. Nine aesthetascs of slightly varied size, largest more than half as long as appendage, reaching tip of rostrum.
Antenna II relatively short. Basal segment robust, with transverse series of fine, long setules, rudimentary distal spine and short setules at distal margin ( Fig. 2F View FIGURE 2 ). Antennal branches elongated, exopod shorter than endopod, all segments cylindrical, 4 long and stout spine-like setules on first and second endopod segment. Antennal formula, setae 0–0–3/1–1–3, spines 1–0–1/0–0–1. On both exopod and endopod three long apical swimming setae slightly different in size, basal and distal lateral setae unequal in size, both shorter than apical setae. Spine on basal segment of exopod long, almost reaching middle of apical segment. Apical spines of exopod and endopod of subequal length, obviously longer than apical segments.
Trunk limb I compact, with a small, globular epipodite ( Fig. 3A View FIGURE 3 ), without accessory seta, ODL large, elongate, narrowing distally, with a row of fine setules and a long seta with distal segment unilaterally armed with short, dense setules ( Fig. 3B View FIGURE 3 ). IDL with three clusters of long marginal setules and three bisegmented setae; different in size but similar in setulation. Endite 3 with soft setae a–c of subequal size, and a long stiff seta 1, armed with fine setules. On endite 2 densely feathered setae d–f, seta d short, setae e–f subequal in length, a rudimentary, naked seta 2 near base. Endite 1 with 2-segmented setae g–i, and a rudimentary seta 3. Fascicles of slender setules on inner face of limb, plus groups of longer, more robust setules on ventral margin. Two ejector hooks of unequal size. A maxillar process not found.
Trunk limb II with small, globular epipodite ( Fig. 3C View FIGURE 3 ). Exopodite ovoid, small, without setae, but with a tuft of short setules. Inner portion of limb with eight scrapers ( Fig. 3C View FIGURE 3 : 1–8). Distalmost scraper 1 with unilaterally setulated basal segment, on distal lobe with basal group of long setules. Few small projections posterior to scrapers 2–3. Portion of gnathobase bordering “endopodite” somewhat inflated, and densely setose. Distal armature of gnathobase with four elements. Filter plate with seven setae, distalmost somewhat shorter than rest, with inflated basal segment and fully setulated, while others armed bilaterally.
Trunk limb III with sub-globular epipodite ( Fig. 3D View FIGURE 3 ). Exopodite trapezium-shaped, with two distal and three lateral setae: seta 1 with unilaterally armed basal segment and fully setulated distal segment, seta 2 specially long, with distal segment armed by alternated short and long setules, lateral setae 3–5 armed in similar manner, but seta 3 specially short. Distal endite with three stiff setae, 1 and 2 with minute setules, 3 armed distally by longer setules. Basal endite with stiff setae 4–7, armed with fine, very short setules distally, bottle-shaped sensillum near seta 4. On posterior limb face, four soft setae ( Fig. 3E View FIGURE 3 : a–d), seta a longest, all armed with long setules distally. Distal armature of gnathobase with four elements. Filter plate with seven bilaterally setulated setae, basalmost and distalmost setae shorter than rest.
Trunk limb IV with setulated pre-epipodite and globular epipodite ( Fig. 3F View FIGURE 3 ). Exopodite wide, subovoid, with six setae, seta 1 shortest, all setae with similar armature of long, fine setules. Inner portion of limb IV with four marginal setae, seta 1 stout, with minute setules distally, 2–4 with inflated basal segments and slender, unilaterally setulated distal segments, in seta 2 basal segment also setulated. On posterior limb face, three soft setae ( Fig. 3F View FIGURE 3 : a, c–d) and a curved sensillum (b). Distal armature of gnathobase with four elements. Filter plate with five setae, distalmost with inflated basal segment and fully setulated.
Trunk limb V with large setose pre-epipodite, and globular epipodite of similar size ( Fig. 3G View FIGURE 3 ). Exopodite large, with four setae. Inner limb portion an elongate, flat lobe, with setose inner margin. On inner face, two setulated setae of unequal length. Distal armature of gnathobase a setulated lobe, two setae in “filter plate”.
Ephippium. Transparent, slightly brown (See Alonso 1996: fig. 162H).
Size. Holotype 1.06 mm; parthenogenetic females from type locality 0.92–1.15 mm.
Differential diagnosis. This species has a series of traits rarely observed in well-studied species of the subgenus L. (Neoleydigia), and never in this combination: (1) PP distance large; (2) numerous, low hillocks on preanal margin of postabdomen; (3) numerous setae in lateral fascicles on postabdomen, plus distalmost and next setae subequal in size; (4) sensory seta shifted to distal end of antenna I, but not so markedly as in L. microps ; (5) fully setulated basal segment of distalmost scraper on limb III; (6) 5 setae on exopodite III.
Distribution and ecology. The species is known only from a single locality in the Mediterranean steppes of the Low Guadalquivir river basin, southern Spain. Longuilla lagoon is a shallow temporary little mineralized (154 µS of water specific conductance) water body. Water was turbid by suspended clay particles. Submerged aquatic vegetation was scarce. The accompanying crustacean community was rich in species, and the characteristic of lakes in the Palaearctic steppes, particularly with clayey waters ( Alonso, 1998): the large branchiopods Triops cancriformis var. mauritanicus Ghigi, 1921 and Streptocephalus torvicornis (Waga, 1842) ; the cladocerans Daphnia bolivari Richard, 1888 , Daphnia hispanica Glagolev & Alonso, 1990 , Scapholeberis rammneri Dumont & Pensaert, 1983 , Moina brachiata (Jurine, 1820) , Macrothrix sp. (still undescribed), Pleuroxus letourneuxi (Richard, 1888) , Dunhevedia crassa King, 1853 , Alona sp. (close to A. azorica Frenzel & Alonso, 1988 , still undescribed) and Alona nuragica Margaritora, 1971 ; the copepods Diaptomus cyaneus Gurney 1909 , Hemidiaptomus roubaui Richard, 1888 , Mixodiaptomus incrassatus G.O.Sars, 1903 and Megacyclops viridis Jurine, 1820 .
Museo Nacional de Ciencias Naturales
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Leydigia (Neoleydigia) iberica
|Kotov, Alexey A. & Alonso, Miguel 2010|
|Alonso, M. 1996: 361|