Alona anastasia, Sinev, Artem Y., Alonso, Miguel, Miracle, Maria Rosa & Sahuquillo, Maria, 2012

Sinev, Artem Y., Alonso, Miguel, Miracle, Maria Rosa & Sahuquillo, Maria, 2012, The West Mediterranean Alona azorica Frenzel & Alonso, 1988 (Cladocera: Anomopoda: Chydoridae) is composed of two species, Zootaxa 3276, pp. 51-68 : 52-60

Alona anastasia sp. nov.

( Figs 1–5 , 7 )

Etymology: the name of the species is from the Greek ανάστασlς 'resurrect', and reflects both ability of the species to survive the drying of waterbody and long story of its description.

Type locality: Lavajo de Abajo, Sinarcas, Valencia province, Spain, 38°06'11" N, 12°40'39" E.

Holotype: Parthenogenetic female from the type locality collected in May 2008 preserved with 4% formaldehyde deposited in the MNCN (Accession number: 20.04/8666).

Paratypes: 25 adult and juvenile parthenogenetic females, and 1 male from type location (May, 2008) preserved with 4% formaldehyde in a vial deposited in the MNCN (Accession number: 20.04/8667). Numerous parthenogenetic and ephippial females and males from the pond “Bassa del Cavall”, Valencia province, Spain, collected January-June 2008 and 2009 are deposited in the collection of Valencia University (M.R. Miracle).

Other material, in Miguel Alonso’s private collection, was collected in the following ponds or shallow lakes (“Lagunas”): Longuilla (Fuentes de Andalucía, Sevilla, April 1979); Miaha (Écija, Sevilla, April 1979); Lantejuela (Lantejuela, Sevilla, April 1979); Turquilla (El Rubio, Sevilla, April, 1979); Cucharas (Villamayor de Calatrava, Ciudad Real, April 1979); Los Corulos (Madrid, May 1987); Parideras (Lagunarota, Huesca, April 1983); Monreal (Fraga, Zaragoza, May 1980); Grande de Albuera (La Albuera, Badajoz, April 1979); Villardón (Villarrín de Campos, Zamora, May 1980).

Diagnosis. Parthenogenetic female. Body regular oval, of moderate height, in adults height/length ratio 0.65– 0.72, maximum height at the middle; body moderately compressed laterally Dorsal margin convex, postero-dorsal and postero-ventral angles broadly rounded. Postero-dorsal angle with about 100 setules not organised into groups. Ventral margin with about 35–45 setae. Head shield with short and rounded rostrum, posterior part of head shield subtriangular, with broadly rounded posterior apex. Three major head pores with a narrow connection only between two anterior pores, distance between medium and posterior pore equal to about 1.0–1.5 distance between anterior and middle pore. Minute lateral head pores located about 0.8 IP distance from midline, at level before anterior major head pore. Labrum of moderate size, labral keel narrow, with convex anterior margin and a rounded apex. Postabdomen of moderate length and width, with parallel margins in postanal portion, length about 2.5 height. Dorsal margin straight in postanal portion, anal margin concave; distal part of postabdomen about 1.5 times longer than preanal one, postanal and anal margins approximately of similar length. Preanal angle well-expressed, postanal angle weakly defined, distal margin straight, dorso-distal angle rounded. Postanal margin with 5 or 6 clusters of 2–4 short denticles. Lateral fascicles of setules well-developed, in postanal portion distalmost setules very long and thick, three times longer than marginal denticles. Postabdominal claw slightly shorter than preanal portion of postabdomen. Basal spine weakly curved, about 0.2 of the claw length. Antenna of moderate size. Antennal formula setae 0-0-3/1-1-3, spines 1-0-1/0-0-1. Seta arising from basal segment of endopodite thin, as long as endopod. Spine on basal segment of exopod slightly shorter than middle segment. Spines on apical segments longer than apical segments. Limb I with accessory seta four times shorter than ODL seta. IDL with three setae, seta 1 well-developed, about 1/3 length of seta 3. Exopodite of limb III with seven setae. Exopodite IV with six setae. Exopodite V with four setae, filter plate V absent. Limb VI absent.

Male. Body low oval, maximum height in the middle of the body, body height/body length = 0.56–0.58 in adult male. Ocellus and eye of same size as in female. Postabdomen strongly narrowing in anal part, with rectangular postanal part and defined posteroventral angle. Postanal angle not defined, preanal angle well-defined. Distal part of postabdomen 1.5 times longer than preanal, anal and postanal parts of dorsal margin of similar length.

Sperm duct openings at the end of postabdomen. Clusters of short setules in place of marginal denticles, lateral fascicles of setules same as in female. Postabdominal claw two times shorter than that of female, with short basal spine about 0.2 length of claw. Antennule with 10 terminal and 2 lateral aesthetascs of similar length, about 2/3 length of antennule. Male seta arising at 1/4 length from tip, reaching to the end of antennule. Thoracic limb I with V-shaped copulatory hook. On ventral face of limb below copulatory brush a row of 20-25 short thick setules. IDL seta 1 absent, setae 2 and 3 short and thin, subequal in length, male seta curved, almost as long as seta 2.

Description. Parthenogenetic female. General. In lateral view regular oval ( Fig. 1 A-D, 2A, 3A), moderately compressed laterally ( Fig. 2 B), of moderate height in adults, low in juveniles. Maximum height at middle of body, in adults height/length ratio about 0.65–0.72. Dorsal margin uniformly curved; postero-dorsal and postero-ventral angles broadly rounded; posterior margin uniformly curved; ventral margin almost straight; antero-ventral angle rounded. Ventral margin with about 35–45 setae, the first ten setae long, next ten setae short, other setae of moderate length. Postero-ventral angle bears about 100 short setules of similar length, not organised into groups ( Fig. 1 E, 3B). Valve oblique or covered with well-expressed tubercles; sculpture of head shield same as that of valves.

Head of moderate size, triangle-round in lateral view, rostrum ( Fig. 3 F) short, pointing downward. Eye larger than ocellus. Distance from tip of rostrum to ocellus in adults slightly greater than that between ocellus and eye. Head shield ( Fig. 1 B, 1F–H) with maximum width behind mandibular articulation; rostrum short, broadly rounded; posterior margin of head shield sub triangular with broadly rounded apex. Three major head pores ( Fig. 1 C, 1I –J, 2C, 3C) with a narrow connection only between two anterior pores, distance between medium and posterior pore equal to about 1.0–1.5 distance between anterior and middle pore. Minute lateral head pores located at level before anterior major head pore.

Labrum ( Fig. 1 K–L) of moderate size; labral keel moderately broad, narrow (height about 1.5 width), with rounded or blunt apex; anterior margin of keel convex, posterior margin with two minute clusters of setules.

Thorax two times longer than abdomen, middle abdominal segment not saddle-shaped.

Postabdomen ( Fig. 3 D, 4A–B) of moderate length and width, with parallel margins in postanal portion, length about 2.5 height. Ventral margin almost straight. Base of claw bordered from distal margin by clear incursion. Distal margin convex, distal angle broadly rounded, not prominent. Dorsal margin straight in postanal portion, anal margin concave; distal part of postabdomen about 1.5 times longer than preanal one, postanal and anal margins approximately of similar length. Preanal angle well-expressed, postanal angle weakly defined. Postanal margin with 5 or 6 clusters of 2–4 short denticles, anal margin with 3 or 4 groups of setules. About 10 well-developed lateral fascicles of setules; additional smaller fascicles in anal portion below the main row. In postanal portion, distalmost setules in fascicles very long and thick, three times longer than marginal denticles. Postabdominal claw ( Fig. 3 E) slightly shorter than preanal portion of postabdomen ( Fig. 4 A-B). Basal spine weakly curved, about 0.2 of the claw length.

Antennule ( Fig. 4 C) of moderate height and width, with length about 2.5 maximum width; with 3 or 4 transverse rows of setules at anterior face. Antennular seta thin, of about half length of antennule, arising at 2/3 distance from the base. Nine terminal aesthetascs of different length, two longest of them of about half length of antennule.

Antenna ( Fig. 3 F, 4D) of moderate size. Antennal formula, setae 0-0-3/1-1-3, spines 1-0-1/0-0-1. Branches with basal segments 1.5 times longer and thicker than two others. Basal segment of exopodite with cluster of long thin setules basally and cluster of shorter setules distally, middle segment with cluster of long setules distally. Seta arising from basal segment of endopodite thin, as long as endopodite. Seta arising from middle segment of endopodite of same size with apical setae. Apical setae of both branches not differentiated. Spine on basal segment of exopodite slightly shorter than middle segment. Spines on apical segments longer than apical segments.

Thoracic limbs: five pairs, limb VI absent.

Limb I ( Fig. 5 A–B). Epipodite oval, with short finger-like projection. Accessory seta short, about 1/4 length of ODL seta. ODL seta with very short setules. IDL with 3 setae and 2 or 3 clusters of setules on ventral face. IDL seta 1 well-developed, about 1/4 length of ODL seta; setae 2 and 3 of similar morphology, with thin setules in distal part; seta 3 as long as ODL seta; seta 2 slightly shorter. Endite 3 with four setae subequal in length. Endite 2 with 3 setae setulated in distal part, longest of them 1.5 times longer than ODL seta. Endite 1 with two 2-segmented setae, both setulated in distal part, without a flat plumose seta shifted to the limb base. No naked setae or sensillae on endites 1–2. Ventral face of limb with 6 or 7 clusters of long setules. Two ejector hooks, one little larger than other.

Limb II ( Fig. 5 C). Exopodite as narrow elongated lobe. Inner portion of limb (“endopodite”) with eight scraping spines, increasing progressively in length distally, armed denticles of similar size. Distal armature of gnathobase with four elements. Filter plate II with seven setae, the posteriormost one considerably shorter than others.

Limb III ( Fig. 5 D–E). Epipodite oval, without projection. Exopodite with seven setae, seta 3 being longest, length of setae 4 and 6 about 1/4 and 1/3 length of seta 3 respectively, other setae shorter. Distal endite with 3 setae, distalmost and middle setae of same size, slender and sharp, with denticles in distal part, basalmost seta short, geniculated, with thin setules. A small sensillum near base of seta 1. Basal endite with 4 stiff, plumose in distal part setae, increasing in size in basal direction. Gnathobase not clearly separated from basal endite. Four soft setae increasing in size basally, an elongated sensillum near the basalmost soft seta. Distal armature of gnathobase with four elements: the first one an elongated, narrowing distally sensillum, the second geniculated seta, and the two others are spines with fused bases. Filter plate with seven setae.

Limb IV ( Fig. 5 F–G). Preepipodite setulated, epipodite oval, without projection. Exopodite rounded, of irregular shape, with 6 plumose setae. Seta 3 being longest; setae 1–2 about 1/2 length of seta 3; setae 4–5 about 1/3 length of seta 3; seta 6 short. Inner portion of limb IV with four hard setae and a lopsided sensillum. Scraping seta with broad base, flaming-torch setae of similar shape, decreasing in size basally. Three soft setae increasing in size basally. Gnathobase with a short 2-segmented seta and a curved projection distally. Filter plate with five setae.

Limb V ( Fig. 5 H): Preepipodite setulated, epipodite oval, without projection. Exopodite oval evenly decreasing in size basally, seta 4 four times shorter than seta 1. Inner limb portion as wide oval lobe, with long setules on the inner margin. At inner face, two distally setulated setae, the distal one 1.5 times longer than proximal. Filter plate absent.

Ephippial female ( Fig. 1 M, 2D) with body of same height as in parthenogenetic female, maximum height before the middle of the body, ephippium dark yellow-brown, with hexagonal sculpture in non-tuberculated specimens, with tubercules in tuberculated specimens.

Male. General shape of juvenile ( Fig. 1 N–O) and adult males ( Fig. 1 P, 2E) similar to that of juvenile females, low oval, maximum height in the middle of the body, body height/body length = 0.56–0.58 in adult male. Ocellus and eye of same size as in female.

Postabdomen. In juvenile males of both instars I and II ( Fig. 4 E) similar to that of female, ventral margin with clear step in the region of gonopores. In instar I and 2, gonopores located at the distance of 1/3 and 1/4 length of ventral margin from the end of postabdomen, respectively. Armament of postabdomen and postabdominal claw same as in female in both juvenile instars. In adult male, postabdomen ( Fig. 4 G–H) strongly narrowing in anal part, with rectangular postanal part and defined posteroventral angle. Postanal angle inverted, obtuse; preanal angle well-defined, protruding. Distal part of postabdomen 1.5 times longer than preanal; anal and postanal parts of dorsal margin of similar length. Sperm duct openings at the end of postabdomen above the base of postabdominal claws. Clusters of short setules in place of marginal denticles, lateral fascicles of setules same as in female. Postabdominal claw two times shorter than that of female, weakly curved, with short basal spine about 0.2 length of claw.

Antennule. In instar I male same as in female. In instar II male antennule ( Fig. 4 F) little broader than in female, with anlage of male seta, and aestetascs same as in female. In adult male, antennule slightly shorter and broader than in female ( Fig. 4 I), with 10 terminal and 2 lateral aesthetascs of similar length, about 2/3 length of antennule. Male seta arising at 1/4 length from tip, reaching to the end of antennule.

Thoracic limb I. In male instar I with short anlage of copulatory hook; IDL same as in female. In male instar II, copulatory hook curved ( Fig. 5 I). Ventral face of limb with anlage of copulatory brush seta and a row of about 8 short setules below it. IDL with anlage of male seta, seta 1 absent, setae 2 and 3 same as in female. In adult male, limb I more stout than that of female ( Fig. 5 J–K), with V-shaped copulatory hook. Copulatory brush present, with several long setules under it, and 20–25 short thick setules on ventral face of limb below them. IDL seta 1 absent; setae 2 and 3 much shorter and thinner than in female, subequal in length; male seta moderately thick, almost as long as seta 2.

Size: minimum length of juvenile female 0.2 mm, maximum length of adult female 0.61 mm. Length of adult male 0.25–0.34 mm.

Differential diagnosis. A. anastasia sp. nov. can be distinguished from most species of Alona s. lato by the morphology of major head pores, being the only known species with similar head pores as its sibling-species, A. azorica . All other species of Alona s. lato have all major head pores either connected or, rarely, disconnected. A. anastasia sp. nov. can be differentiated from A. azorica by the morphology of head shield and head pores, and by the shape of male postabdomen.

A. anastasia sp. nov. (0.61 mm female maximum length) is also bigger than A. azorica (0.48 mm). Posterior part of head shield forms an acute angle in A. azorica whereas in A. anastasia sp. nov. it is subtriangular and more rounded. Posterior pore is gradually separated from medium pore as the animal grows ( Fig. 6 ) in A. azorica so that distance between medium and posterior pores is 1.5–2.5 times greater than that between anterior and medium pores, whereas in A. anastasia sp. nov. such ratio is 1.0–1.5. The male postabdomen, has a more narrow, rectangular postanal portion in A. anastasia sp. nov..

Ecology of A. anastasia sp. nov. populations from Valencia Province, Spain. Living individuals of this species were found in only three ponds among over 140 freshwater ponds studied in Valencian Autonomous Community. These three ponds were all temporary and on siliceous substrate. Holotypes and paratypes were collected from two of these sites which were selected by EPCN as “Important Areas from Ponds” (IAP’s, Ewald et al. 2010) and are described herein.

Lavajo de Abajo (Sinarcas) is a endorheic, temporary pond located at 869 m a.s.l., in the western part of Valencia province about 100 km from the coast, on the border of the Central plateau. It is catalogued as a “priority habitat for conservation: Mediterranean temporary ponds” (MTPs, Natura code: 3170*, according to the Habitat Directive of the European Union (92/43/EC) and it is a flora micro-reserve area. The pond lies in a natural depression made up of Plio-Quaternary siliciclastic deposits (rañas) lying on top of Miocenic sediments, under a continental Mediterranean climate. Mean annual rainfall is 565 mm and mean annual temperature is 13.2°C, for the 10 year period: 1999–2008. In winter night frosts are frequent and in summer months average temperatures are over 20°C. Main rainfall occurs in autumn and spring while summers are hot and dry and the pond dries up usually in early or mid-summer. The hydroperiod is usually large, about 9 months, but it depends on rainfall, in wet years water is hold from late-autumn to mid-summer (as occurred in 2007), but in dry years alternating wet and dry periods occur during late autumn and winter. The pond is one of the largest in this area, with a typical circular shape. In spring of a normal year (such as 2007) it may attain a surface of 1 ha with a maximum depth of 1.8 m. It is currently surrounded by agricultural fields, but has a rich vegetation catena of amphibious (with Isoetes and Marsilea ), helophitic (with Eleocharis ) and macrophitic vegetation (with Chara , Ranunculus and Miriophyllum). Some of these communities belong to Isoete-Nanjuncetea class that, according to Mansanet & Mateo (1978), represent a disjoint oriental location from the normal area of distribution, situated more westwards. This location could be interpreted as a relict area of this kind of vegetation. Plants are covered with metaphyton especially in winter and early spring The crustacean community of this pond is rich and singular, indicating also its relict character. For instance, in this pond are found large Branchiopods such as Branchipus cortesi, Maghrebestheria maroccana and Triops cancriformis ( Miracle et al. 2008) . The microcrustacean community is characterized by the presence in winter of calanoids, the large and rare Hemidiaptomus ingens , accompanied by Diaptomus cyaneus and Mixodiaptomus laciniatus atlantis followed by a complete shift in spring to a community of cladocerans (undescribed Ceriodaphnia sp. in early spring and Moina micrura peaking afterwards) with a good representation of chydorids, such as Ephemeroporus phintonicus and Dunhevedia crassa ( Sahuquillo & Miracle 2010) .

Bassa del Cavall is a medium size pond, a little more than 0.1 ha with a maximum depth of 0.9 m, located in the top of a small sandstone hill (211 m a.s.l.) covered by a well developed Mediterranean woodland. It belongs to Calderona Mountain Range and is a flora micro-reserve area. Due to its closeness to the sea coast it has a mild weather (mean annual rainfall 585 mm, mean annual temperature 17°C, average for the years 1999–2008). Water temperatures measured during sampling dates ranged between 10 and 20ºC. It has usually several flooding periods alternating with dry periods from late autumn to late spring, the wet phases varying from 1 to 6 months. During all the year the pond is vegetated and the water has a brown colour; terrestrial vegetation colonizes the pond when dried up and during the wet phase several rings of aquatic vegetation develop. Ranunculus sp. is usually the dominant macrophyte, which is also covered by metaphyton. The crustacean community is characterized, like in Sinarcas, by the preponderance of H. ingens in winter and the abundance of Ceriodaphnia sp. in spring followed by Moina micrura at the end of this season. However, in this pond A. anastasia sp. nov. is the dominant cladoceran, being always present.

Population Dynamics. Alona anastasia sp. nov. appears in winter at low densities and with maximum densities of ovigerous females in spring, when there is well-developed macrophyte coverage and temperatures are between 12 and 22°C. In Sinarcas, where density is smaller than in Cavall, the population may start to build up later ( Fig. 7 a) in the years of low rainfall (especially low spring rains). Gametogenesis takes place in late spring (June). However in Cavall, where hydroperiod is shorter than in Sinarcas and rain-dependent ( Fig. 7 b), males and ephippial females appear when the water body is close to dry up, what could happen in mid spring (as in the year 2008 with low spring rains). If in late spring the pond holds water again, another population develops with gametogenesis taking place again in this second wet phase. In the study year, at the beginning of the second wet period, males appeared immediately after water refilling (12% of the individuals) together with few ephippial females. A. anastasia sp. nov. in Cavall was found always, during the whole wet phases reaching very high densities (maximum of 560 individuals/ l at the beginning of April 2008, Fig. 7 b). Across the year a reduction in body size and in size at maturity could be observed ( Table 1, Fig. 7 ). In January individuals reached their largest size (max. 0.61 mm). During the second wet phase in late spring, body size was significantly smaller (both size at maturity and body size of the population). The mean number of eggs per clutch was also lower in the second wet period, due to a higher proportion of females bearing only one egg, instead of two as was normal in the first wet period.

Cavall Mean max min N Sinarcas Mean max min N Total 364 610 200 849 Total 343 590 220 93 Female 2 eggs 449 610 330 224 Female 2 eggs 393 450 350 21 Female 1 eggs 394 490 320 77 Female 1 eggs 363 400 340 13 Female 0 eggs 325 590 200 501 Female 0 eggs 310 590 220 44 Female ephip. 411 460 370 10 Female ephip. 410 410 410 1 Male 309 340 280 35 Male 306 330 250 8

Figures

FIGURE 1. Alona anastasia sp. nov. from Bassa del Cavall pond, Valencia, Spain. A – С, juvenile female of instar II: A, lateral view; B, head shield; C, head pores. D – L adult parthenogenetic female: D, lateral view; E, posteroventral angle of valve; F – H, head shields; I – J, head pores; K – L, labrum; M, ephippial female; N – O, juvenile males of instars I and II; P, adult male. Scale bars 0.1 mm for A – B, D, F – H, M – P; 0.05 mm for C, E, I – L.

FIGURE 2. Alona anastasia sp. nov. Laguna de Cucharas, Villamayor de Calatrava, Ciudad Real, Spain. A – C, parthenogenetic female: A, lateral view; B, outline in dorsal view; C, head pores; D, ephippial female; E, adult male. Scale bars 0.1 mm for A – B, D – E; 0.05 mm for C.

FIGURE 3. Alona anastasia sp. nov. Laguna de Cucharas, Villamayor de Calatrava, Ciudad Real, Spain. Parthenogenetic female: A, lateral view; B, posteroventral angle of valve; C, head pores; D, postabdomen; E, postabdominal claw; F, antenna.

FIGURE 4. Alona anastasia sp. nov. from from Bassa del Cavall pond, Valencia, Spain. A – D, parthenogenetic female: A – B, postabdomen; C, antennule; D, antenna. E – F, juvenile male of instar II: E, postabdomen; F, antennule. G – I, adult male: G – H, postabdomen; I, antennule. Scale bar 0.05 mm.

FIGURE 5. Alona anastasia sp. nov. from from Bassa del Cavall pond, Valencia, Spain. A – D, thoracic limbs of parthenogenetic female: A, limb I; B, IDL of limb I; C, limb II; D – E, exopodite and inner portion of limb III; F – G, exopodite and inner portion of limb IV; H, limb V; I, limb I of juvenile male of instar II; J – K, limb I of adult male. Scale bar 0.05 mm.

FIGURE 6. Distance between head pores in relation to body size in two populations of Alona azorica (Antela, Marzagón) and two populations of A. anastasia sp. nov. (Monreal, Cucharas).

FIGURE 7. Population dynamics of Alona anastasia sp. nov. in the ponds: (a) Lavajo de Abajo during the wet phases of two years differing in spring pluviosity and (b) Bassa del Cavall in two discontinuous wet phases of the same year. Densities, expressed in individuals / L, are the averages of samples taken in two sampling points. Pond depth at the time of sampling and daily rainfall from the nearby meteorological stations is also indicated. Additionaly in Bassa del Cavall, water and air temperature are indicated. In the two bottom graphs the seasonal variation of body size of A. anastasia sp. nov population from Bassa del Cavall is showed: mean size of the whole population (grey circle) with its standard deviation and size at first maturity (SFM, black circle)