Daphnia (Ctenodaphnia) paggii, Kotov & Sinev & Berrios, 2010
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https://doi.org/ 10.11646/zootaxa.2430.1.1 |
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https://treatment.plazi.org/id/03A987D7-FFF8-3F03-90D9-FED83E0BFC21 |
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Felipe |
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Daphnia (Ctenodaphnia) paggii |
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sp. nov. |
Daphnia (Ctenodaphnia) paggii View in CoL sp. nov.
( Figures 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )
Etymology. This species is dedicated to Dr Juan C. Paggi, renowned Argentinean investigator of the South American Cladocera .
Type locality. Salar de Lagunillas ( Table 1: locality 3).
Holotype. Adult parthenogenetic female, MGU Ml 83. Label of the holotype: " Daphnia paggii sp. nov., 1 parth. ♀ from Lagunillas Salt Lake , North Chile, coll. in summer 2002, HOLOTYPE ".
Allotype. Adult male, MGU Ml 84.
Paratypes. Five parthenogenetic females, MGU Ml 85; three males, MGU Ml 86; one ephippial, one preephippial and three parthenogenetic females, AAK 2008-156 .
All type specimens are in 90% alcohol.
Short diagnosis. Parthenogenetic female. Body almost transparent, subovoid, lacking a caudal spine, a distinct depression between head and rest of body. Rostrum short and rounded, ventral margin of head with shallow pre-ocular and post-ocular depressions, eye capsule located significantly below the level of anteriormost point of head; ocellus present Head shield with slightly projected, rounded fornices, a projection from valves penetrates to about 1/2 of head shield length. Secondary fornix short. A group of relatively long setae in middle of ventral margin, short setae at postero-ventral margin of valve, no setules between them. First abdominal segment with a relatively short (as long as postabdominal claw) process, slightly bent anterior; second segment with a small process, the third segment with a very low, mound-like process; the fourth segment lacking a process. Preanal angle of postabdomen ill-defined, postanal angle not expressed. On outer side of postabdominal claw, the first and second (proximal) pectens and the third (medial) pecten consisting of numerous thin teeth, each approximately two times shorter than claw diameter; the fourth pecten consisting of numerous fine setules not reaching the tip of claw. Body of antenna I well-developed, tips of aesthetascs projected beyond tip of rostrum, antennular sensory seta arise from base of mound of the antenna I and not reaching tip mound. On limb I setae 1-3 long, bearing short setules distally, seta 4 long, with long setules. Limb II with seta 1 somewhat longer than half of a soft seta near it; gnathobase with four anterior setae and 16–19 posterior setae. Limb III with seta 2 of exopodite bearing short setules; inner-distal portion of limb III with setae 1, 2 and 3 long, seta 4 shorter than each of the latter. Gnathobases III–IV with numerous posterior soft setae. Limb V with exopodite supplied with two distal setae and a long, curved lateral seta.
Ephippium darkly pigmented, "O"-shaped, two eggs with axes almost parallel to main body axis and located at a very acute angle to dorsal margin, anterior process long, but a posterior process fully absent, postero-dorsal portion of valves incorporated into ephippium.
Adult male. Body elongated, dorsal margin of valves almost straight, very slightly elevated above head, distinct depression between head and valves, postero-dorsal angle distinct, but without a caudal spine. Head with rounded rostrum. Abdomen without processes on each of its segments. Postabdomen with distal portion as a short tube, gonopore opens subdistally, without a genital papilla. Antenna I long, antennular sensory seta thin, located distally on end of antenna I body; flagellum long, bisegmented, its distal segment setulated.. IDL of limb I with a bent copulatory hook, and two setae of very different size; anterior setae 2, 3 and 4 smaller that these in female and supplied with long, fine setules. On distalmost endite of limb II, anterior seta 1 slightly bent and asymmetrically setulated.
Size. Females up to 2.40 mm, males 1.49–1.81 mm
Description. Adult parthenogenetic female. Body almost transparent, subovoid in lateral view, with maximum height in middle, anteriormost and posteriormost extremities of body lies at the level of longitudinal body axis, dorsal margin of valves elevated above head, regularly convex ( Fig. 1A View FIGURE 1 ), a distinct depression between head and rest of body. Postero-dorsal angle in adults lacking a caudal spine, as a rounded triangle (while smaller females bear a very short caudal spine), ventral margin regularly convex. In ventral view body ovoid, moderately compressed laterally ( Fig. 1B View FIGURE 1 ).
Head with a short, rounded rostrum ( Figs 1A, C–D View FIGURE 1 ), without a pre-rostral fold (see Ishida et al. 2006; Kotov et al. 2006); posterior margin of head straight; ventral margin of head with shallow pre-ocular and postocular depressions ( Fig. 1D View FIGURE 1 , arrows). Eye capsule located significantly below the level of anteriormost point of head. Compound eye relatively small, ocellus distinct, although minute, located far from base of antenna I. In ventral view, head with two depressions, delimiting its topmost portion ( Fig. 1E View FIGURE 1 , arrows). Head shield widest in middle, with slightly projected, rounded fornices, a projection from valves penetrates to about 1/2 of its length ( Fig. 1F View FIGURE 1 , arrow). Labrum with a wide, fleshy main body supplied distally with series of setules, and a setulated distal labral plate ( Fig. 1C View FIGURE 1 , arrow).
Carapace subovoid, secondary fornix short ( Fig. 1A View FIGURE 1 , arrow), spinules present on whole dorsal margin and on posterior half of ventral margin. A group of relatively long setae in middle of ventral margin ( Fig. 1G View FIGURE 1 ), short setae at postero-ventral margin of valve ( Fig. 1H View FIGURE 1 ), no setules between them as in some other species of Daphnia (see Alonso 1996; Ishida et al. 2006).
Abdomen relatively short, consisting of four segments, the first (basal most) abdominal segment with a relatively short (as long as postabdominal claw) process, slightly bent forward; the second segment with a small process, the third segment with a very low, mound-like process, covered by transverse rows of minute setules; the fourth segment without a process, with slightly convex dorsal margin ( Figs 1I–J View FIGURE 1 , each segment is marked by an arrow).
Postabdomen elongated, tapering distally, with ventral margin in general slightly convex, lacking of setules ( Figs 1I–J View FIGURE 1 ). Preanal margin long, almost straight, with series of minute setules. Preanal angle ill-defined, postanal angle not expressed. Numerous small paired spines of subequal size on anal portion. Postabdominal seta somewhat longer than preanal margin, its distal and basal segments of similar length. Postabdominal claw regularly bent, with a pointed tip. On outer side, four successive pectens along the dorsal margin ( Fig. 1K–L View FIGURE 1 , each pecten is marked by arrow): the first and second (proximal) pectens and the third (medial) pecten consisting of numerous thin teeth, each approximately two times shorter than claw diameter; the fourth pecten consisting of numerous fine setules, somewhat shorter than those in the second pecten, not reaching the tip of claw, inner side of claw with uniform setules. Rows of denticles at ventral margin of the claw.
Body of antenna I well-developed, with nine aesthetascs of different length terminally ( Figs 2A–C View FIGURE 2 ), their tips projected beyond tip of rostrum, antennular sensory seta ( Fig. 2B–C View FIGURE 2 , arrow) fine, arise from base of mound of the antenna I, short, not reaching tip of mound. Antenna II with coxal part possessing two short sensory setae of different length ( Figs 2D–E View FIGURE 2 ). Basal segment elongated, distal sensory seta on its posterior face (not represented in our figures) remarkably longer than the basal segment of exopod, minute distal spine at its anterior face ( Fig. 2D View FIGURE 2 , arrow). Antennal branches somewhat longer than basal segment, all with series of minute setules. Spines on apical segments rudimentary ( Figs 2F–G View FIGURE 2 ), spine on the second segment of exopod small (its length about half of diameter of third segment) and thin ( Fig. 2D View FIGURE 2 ). Antennal formula: setae 0–0–1–3/1–1– 3. Swimming setae subequal in size, each seta with basal and distal segments bilaterally setulated, no chitinous insertion within distal segment ( Fig. 2H View FIGURE 2 ).
Maxilla I as a mound with three seulated setae ( Fig. 3A View FIGURE 3 ).
Limb I without accessory seta; outer distal lobe ( Fig. 3B View FIGURE 3 : ODL), with a long seta bilaterally armed distally with short setules, and a short second seta; inner distal lobe ( Fig. 3B View FIGURE 3 : IDL), or endite 4, with a single, long anterior seta 1, unilaterally armed distally with short setules. Endite 3 with a long anterior seta 2 and two posterior setae (a–b). Endite 2 with a long and thin anterior seta 3, bilaterally armed distally with short setules, and two posterior setae (c–d). Endite 1 with a long anterior seta 4, armed with long, fine setules distally, and four posterior setae (e–h). Two ejector hooks of different length.
Limb II with a subovoid epipodite; distal portion as an elongated lobe bearing a soft, distal seta, and a large, soft, lateral seta. Four endites bearing five setae, among them, a stiff anterior seta ( Fig. 3D–E View FIGURE 3 : 1) somewhat longer than half of the soft seta on this endite, armed with short setules distally, a rudimentary seta ( Fig. 3D View FIGURE 3 : arrow) on endite 2 (the third one from distal end). Gnathobase with two rows of setae: four anterior setae ( Fig. 3F View FIGURE 3 : 1–4), the longest seta 2 as long as a 'filter plate' seta) and numerous (16–19) posterior setae of gnathobasic filter plate (a–p).
Limb III with a large, setulated pre-epipodite, ovoid epipodite and a flat exopodite bearing four distal setae ( Fig. 3G View FIGURE 3 : 1–4), among them seta 2 distally with short setules, and two lateral ( Fig. 3G View FIGURE 3 : 5–6) setae. Innerdistal portion of limb with four endites: endite 4 with a single, long anterior seta, armed distally with short setules ( Fig. 3H View FIGURE 3 : 1) and a posterior ( Fig. 3H View FIGURE 3 : a) seta, bearing long setules; endite 3 with a single anterior seta (2) and a single posterior (b) seta, both with long setules; endite 2 with a large anterior seta (3) and two posterior setae (c–d); endite 1 with a relatively small anterior seta (4) and four posterior (e–h) setae. The rest of the limb inner-distal portion as a singular large lobe, modified gnathobase, bearing numerous (about 80) posterior soft setae, each with chitinous insertion within basal portion of distal segment ( Fig. 3I View FIGURE 3 ), a single, relatively long anterior seta ( Fig. 3H View FIGURE 3 : 1) in its distal corner, and two short anterior setae (2 and 3) in middle of the filter comb. Limb IV with a large, setulated pre-epipodite, ovoid epipodite and a wide, flat exopodite, bearing four distal and two lateral setae ( Fig. 3J View FIGURE 3 : 1–6). Inner-distal portion of this limb with completely fused endites, distally with two setae of unclear homology ( Fig. 3K View FIGURE 3 ), the most part of limb inner margin is a gnathobase filter plate consisting of numerous (about 55–60) posterior setae.
Limb V with a small, setulated pre-epipodite, large, subovoid epipodite, triangular exopodite supplied with two distal setae, among them, more proximal seta rudimentary, and a large, curved lateral seta ( Fig. 3L View FIGURE 3 ). Inner limb portion as an ovoid flat lobe, with setulated inner margin and a single, large seta.
Ephippial female. In contrast to parthenogenetic female, the dorsal margin of the valves is stronger elevated above head, stronger convex in anterior portion and straight in posterior 2/3 of dorsum ( Fig. 2I View FIGURE 2 ), dorsal wall of carapace additionally chitinised, forming a dorsal plate, supplied with series of fine spinules ( Fig. 2K View FIGURE 2 ). In anterior view dorsal portion of body strongly compressed laterally ( Fig. 2J View FIGURE 2 ). Ephippum “O-shaped” (terminology of Paggi 1996), the most part of ephippium darkly pigmented and covered with sculpturing of small rounded cells, anterior process long, but a posterior process fully absent, postero-dorsal portion of valves incorporated into ephippium. Two resting eggs, axes of which almost parallel to main body axis and located under a very acute angle to dorsal margin, egg chambers not separated from each other.
Adult male. Body elongated, in general subovoid, dorsal margin of valves almost straight, very slightly elevated above head, distinct depression between head and valves, postero-dorsal angle distinct, but without a caudal spine ( Fig. 4A View FIGURE 4 ). Head with a rounded rostrum, a small depression on posterior margin of head ventrally to antenna I joint ( Fig. 4B View FIGURE 4 ). Ventral margin slightly concave, anterior most extremity completely occupied with optic vesicle, in some males a shallow supra-ocular depression dorsally to it ( Fig. 4A View FIGURE 4 , arrow), another shallow depression between first and second bunches of muscles of antenna II ( Fig. 4A View FIGURE 4 , arrow). Eye relatively small for a male of this subgenus, ocellus minute.
Valve with anterior margin almost straight, supplied with exactly marginal, relatively short setae; anteroventral angle prominent anteriorly, supplied with specially long setae ( Figs. 4C–D View FIGURE 4 ); whole ventral margin with numerous setae located submarginally on inner face of valve ( Figs 4C–F View FIGURE 4 ). Postero-ventral portion of valve with marginal denticles, and short setae located submarginally on inner face of valve, no setules between these setae ( Figs. 4G–H View FIGURE 4 ).
Abdomen without processes on each of its segments ( Figs. 4I View FIGURE 4 ). Postabdomen with preanal margin shorter than in female, expressed preanal angle, and distal portion as a short tube, gonopore opens subdistally, without a genital papilla ( Fig. 4J–K View FIGURE 4 , arrow). On anal margin, teeth finer than in female. Postabdominal claw short, on its outer surface a two more basal pectens consisting of long and stout setules, and third pecten consisting of numerous finer and shorter setules ( Fig. 4L View FIGURE 4 ).
Antenna I long, slightly and regularly curved, with series of fine setules ( Figs. 4B View FIGURE 4 ); antennular sensory seta thin, located distally on end of antenna I body ( Figs. 4M View FIGURE 4 , arrow); aesthetascs of different length, largest aesthetasc longer than antenna I maximum diameter. Male seta (flagellum) on top of a low, conical, distal (post-aesthetasc) process. This seta long, bisegmented, its distal segment setulated. Antenna II as in female ( Fig. 4N View FIGURE 4 ), no additional hairs on any segments of exopod or endopod, which are found in many other species. Limb I: ODL large ( Fig. 4O View FIGURE 4 ), bearing a rudimentary seta and a very large seta supplied with minute setules distally ( Fig. 4P View FIGURE 4 ); IDL with a bent copulatory hook, and two setae (1 and 1') of very different size, seta 1’ naked; in contrast to female, endite 3 with four setae (additional naked seta of unclear homology marked as 2’, a small sensillum near it), setae 2, 3 and 4 shorter than those in female and supplied with long, fine setules.
Limb II: distal most endite with seta 1 slightly bent and asymmetrically setulated ( Fig. 4Q View FIGURE 4 ).
Size. Holotype 2.10 mm, parthenogenetic females 1.35–2.20 mm; ephippial female 2.40 mm; allotype 1.81 mm; adult males 1.49–1.81 mm.
Differential diagnosis. Daphnia paggii sp. nov. belong to a group of D. ( Ctenodaphnia ) species with rounded fornices ( Alonso 1985; Glagolev 1986, 1995). D. paggii sp. nov. differs from D. atkinsoni Baird, 1859 , D. bolivari Richard, 1888 and D. triquetra Sars, 1903 in absence of a dorsal extension of the carapace into the head shield that forms a heart-shaped lobe. Our new taxon is close to D. mediterranea Alonso, 1985 , D. dolichocephala Sars, 1895 and D. salina Hebert & Finston, 1993 (but the former two have projected, not rounded fornices). But specially, D. paggii sp.nov is close to D. menucoensis Paggi, 1996 . Paggi (1996) analysed the species discrimination within this group in detail, and we agree with his conclusions on the species discrimination, so we are concentrated on differences of our new taxon from D. menucoensis only. Daphnia paggii sp. nov. differs from the former in: (1) distinct ocellus; (2) short and rounded rostrum; (3) very short abdominal processes of first and second abdominal segments; (4) smaller seta of ODL specially short, less that twice thicker than large seta diameter; (5) apparently shorter seta 1 on inner-distal portion of limb II; (6) seta 4 of limb I in female supplied with long setules; (7) dorsal part of carapace of ephippial female strongly curved in anterior portion; (8) a posterior process of ephippium fully absent (rare character in representatives of the subgenus Ctenodaphnia ) and postero-dorsal angle of carapace incorporated into ephippium; (9) male gonopores are not split-like; (10) seta 1’ of male IDL rudimentary; (11) seta 1 on inner-distal portion of limb II with longer setules. Just characters of gamogenetic specimens seems to be most valuable for differentiation of this species from its congeners, as it was found for other anomopods ( Kim et al. 2006; Kotov et al. 2009).
Comments. Daphnia (Ctenodaphnia) paggii sp. nov. could not be associated with any of clades revealed in South America by Adamowicz et al. (2004, 2009) genetically, including their undescribed new species.
Distribution. D. paggii sp. nov. is known only from its type locality. Apparently this is an Andean high mountain endemic, preferring salt waters as does its closest relative, D. menucoensis (see Paggi 1996).
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.
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