Research Article |
Corresponding author: Francisco Diogo R. Sousa ( fdiogo.rs@gmail.com ) Academic editor: Alan Myers
© 2016 Francisco Diogo R. Sousa, Lourdes Maria Abdu Elmoor-Loureiro, Sandro Santos.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Sousa FDR, Elmoor-Loureiro LMA, Santos S (2016) Position of the dentifera-group in the Coronatella-branch and its relocation to a new genus: Magnospina gen. n. (Crustacea, Chydoridae, Aloninae). ZooKeys 586: 95-119. https://doi.org/10.3897/zookeys.586.8209
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Magnospina gen. n. was created to relocate species of the dentifera-group from Alona sensu lato (Crustacea: Cladocera) and include Magnospina dentifera comb. n. and Magnospina siamensis comb. n. The synapomorphies of the Magnospina gen. n. are (1) basal spines longer than 2/3 of the postabdominal claw, (2) presence of 1–4 large denticles, broad at their bases, protruding downwards, without setules between them. Morphological traits such as habitus, rostrum and postabdomen shape, armature of IDL setae, number of setae on the exopod of limb III are also important in the distinction between Magnospina gen. n. and other genera from the Coronatella-branch. The morphology of Magnospina dentifera comb. n. male confirms the closer relationship with the clade composed by the elgans-group from Alona sensu lato, Ovalona and Leberis, but the external morphology, morphology of the postabdominal claw, basal spine and setae 2–3 of IDL support their separation from any of the group cited. It is concluded that the Coronatella-lineage of Aloninae is composed of the genera Coronatella, Anthalona, Karualona, Bergamina, Extremalona, Ovalona, Celsinotum, Leberis and Magnospina gen. n. The elegans-group from Alona sensu lato also belongs to Coronatella-lineage, but still need formal allocation.
Alona broaensis , Alona dentifera , Alona siamensis , Celsinotum , Leberis , male, morphology, Ovalona
The taxonomic status of Alona dentifera (Sars, 1901) (Crustacea: Cladocera) was discussed by
Likewise, the position of A. dentifera is doubtful because its morphology is very different from that of the “true Alona”, which is represented by the quadrangularis-group only (
Thus, our aim is to evaluate the morphological traits of Alona dentifera, based on original material from Brazil and Argentina, and to describe the adult male, for the first time. Additionally, we relocate A. dentifera to a new genus, which also includes A. siamensis.
The description of the new genus was based on material collected in different localities in Brazil and Argentina (see material examined) and data from the literature (
The following abbreviations were used in the text, table and figures:
A1 antennule
A2 antenna
as accessory seta
CBS copulatory brush seta
en endite
ep epipod
ex exopod
fc filter comb
gfp gnathobasic filter plate
gn gnathobase
IDL inner distal lobe
il inner lobe
ms male seta
ODL outer distal lobe
P1-4 limbs I-IV
PA postabdomen
pep pre-epipod
s sensillum
FDRS Personal collection of Francisco Diogo R. Sousa
CLLA Slides collection of the GEEA, at Universidade Católica de Brasília, Brazil
ZMOU
Magnospina dentifera comb. n. = Alona dentifera (Sars, 1901).
The name “Magnospina” is derived from two Latin words, magna = large, long and spina = spine. The generic name refers to the long basal spine on the postabdominal claw.
Parthenogenetic female.Habitus without dorsal keel, ovoid or with moderate lateral compression, length 0.32–0.48 mm, maximum height before the mid-length of body; body height/length about 1.3-.17. Head Eye and ocellus of subequal or different sizes. Rostrum short from a lateral view, wide from a frontal view, not pointed, rounded or truncated; head shield wide, with the distance between the mandibular articulations higher than length of its posterior portion, with or without ornamentation; head pores absent or presents, in last case three connected main head pores, lateral head pores minute. Labral keel wide, oval and naked, apex not elongated. Carapace ornamentation not evident, slightly punctuated or with narrow longitudinal lines; valves armed with 40–53 setae internally inserted at the ventral margin and differentiated in three groups, setae from the anterior group markedly longer than median and posterior groups; ventral margin with a distinctive rounded angle at 1/3 of the length of the margin. Anteroventral corner of valves rounded; posteroventral corner armed with 1–4 large denticles, broad at their bases, protruding downwards, without setules between them; posterodorsal corner poorly defined. Posterior margin almost straight, armed with inner setules on the carapace which are not arranged in groups. Antennule not exceeding the tip of the rostrum, about 2.5 times as long as it is wide; three or four rows of setules on the antennular body. Antennular sensory seta about 1/2 length of antennular body. Nine aesthetascs of different length present in a distal position not exceeding the length of antennular body. Antenna with formula of antennal setae 003/113, spines 101/001; first segment of endopod and exopod elongated, about two times longer than the others segments; weak setules or spicules on the segments. First exopod segment with a narrow, naked or plumose seta, with length similar or slightly longer than the branches. Spine on the first endopod segment longer than second endopod segment. Apical spines slightly longer than the apical segments or about two times shorter than the apical segment itself. Three plumose apical setae not differentiated in size among themselves. Postabdomen approxamately 1.3–2.5 times as long as wide, narrowing distally. Dorsal margin weakly convex or straight. Preanal angle clearly prominent; preanal, anal and postanal margins of different length; postanal margin about 1.5–1.8 longer than anal margin, armed with 9–13 marginal denticles, of which the most distal (1–4) might be individualized, proximal denticles organized in clusters; 8–10 lateral fascicles with setules relatively weak. Postabdominal claw inserted on the projection of postabdomen, 1.3–1.5 times longer than anal margin; spinules on the ventral margin may be present; pecten of spinules on the internal and external face of claw, median pecten with strong spinules; base of the claw armed with 1–5 long and strong spinules. Basal spine almost straight, remarkably long, longer than 2/3 of the postabdominal claw length, with or without spinules on the dorsal margin. First Maxilla with two setulated setae. Limb I with epipod oval, with a finger-like projection. ODL with bisegmented seta, serrated from middle portion towards the distal portion; accessory seta implanted near the base of the ODL. IDL (en 4) with two robust setae (2–3), seta (1) rudimentary or absent; IDL setae 2–3 thick, armed with thick basal denticles. Endite 3 with four setae, anterior seta (1) shorter or similar in length to posterior setae (a-b); setae (a-b) of similar or different length; a sensillum might be present on the endite. Endite 2 with three posterior long setae (d-f) which differ strongly in length among themselves; seta (d) shorter than the seta (e), setae (e-f) with thick spinules on the lateral face; a sensillum might be present on the endite. Endite 3 armed with three posterior setae (g-i); seta (i) plumose, about 1/2 of the setae (g-h). Ejector hooks relatively short. Ventral face of the limb with six-seven groups of setules organized in clusters. Limb II with exopod elongated, short seta present which might be plumose, about two-three times shorter than exopod itself. Inner portion armed with eight scrapers not specialized and decreasing in length towards distal portion, but with some denticles on the scrapers 6–8; anterior soft setae absent; gnathobase armed with four elements, filter comb armed with seven setae, of which two proximal are shorter than the others. Limb III with pre-epipod rounded and setulated, epipod oval with a short finger-like projection. Exopod with four distal and two lateral setae; fifth and sixth setae differentiated in length, third and fourth setae long; second seta about 1.4–1.7 times longer than first setae. Setae 3–6 clearly plumose. Distal endite armed with three setae and one sensillum, setae 1–2 scraper-like of different length; third seta curved and armed with many bilaterally implanted setules (3); four plumose posterior setae present. Basal endite with four soft anterior setae increasing in length towards the gnathobase, a sensillum might be present. Gnathobase with three elements, filtercomb with seven setae. Limb IV with pre-epipod rounded or rectangular and setulated, epipod oval with a long finger-like projection. Exopod with six marginal setae; first and second setae long, not plumose; third seta plumose, short, about two times shorter than the second seta; fourth seta long and plumose; fifth and sixth setae plumose and with similar lengths; Distal endite with four setae (1–4), one scraper-like (1), three flaming-torch-like (3–4); flaming-torch setae not modified. Basal endite with three slightly setulated soft setae. Gnathobase armed with a setulated seta shorter than the length endite itself, filter comb with five setae. Limb V with pre-epipod rounded or rectangular and setulated, epipod oval with a long finger-like projection. Exopod not divided in lobes, armed with four plumose setae. Setae 2–4 of subequal lengths; first seta about two-three times shorter than the other setae. Internal lobe wide, oval and with long setules apically and laterally implanted; two setulated setae on the inner face which are shorter than the length of lobe itself. Filter comb with one or without seta. Limb VI absent.
Adult male. As for Magnospina dentifera comb. n.
Parthenogenetic female.Habitus ovoid, without dorsal keel. Head with rostrum wide, not pointed; head shield wide with distance between mandibular articulations higher than length of its posterior portion, main head pores absent in adults of M. dentifera comb. n. or with three connected main head pores in M. siamensis comb. n.; lateral head pores absent (M. detifera comb. n.) or present (M. siamensis comb. n.). Labral keel wide and naked, apex not elongated. Carapace ornamentation not evident, punctuated or with narrow longitudinal lines; valves armed with 40–53 setae internally inserted at the ventral margin and differentiated in three groups, setae from the anterior group markedly longer than median and posterior groups; ventral margin with a distinctive rounded angle at 1/3 of the margin length; posteroventral corner armed with 1–4 large denticles, broad at their bases, protruding downwards, without setules between them. Antennule not exceeding the tip of the rostrum, nine aesthetascs of different lengths present distally. Antenna with formula of antennal setae 003/113; spines 101/001; basal segments on the exopod and endopod about two times longer than the other segments; weak setules or spicules on the segments. Postabdomen narrowing distally, preanal angle prominent; postanal margin armed with 9–13 marginal denticles which the most distal (1–4) might be individualized, proximal denticles organized in clusters; eight-10 lateral fascicles with weak setules. Postabdominal claw inserted on the projection of postabdomen, longer than anal margin; spinules on the ventral margin may be present; pecten of spinules on the internal and external face of the claw, base of claw armed with 1–5 long and spinules. Basal spine remarkably long, longer than 2/3 of postabdominal claw length, with or without spinules on the dorsal margin (absent in M. siamensis comb. n.). Limb I with endite 1 armed with three setae (g-i); IDL (en 4) with two robust setae (2–3), seta 1 rudimentary (M. dentifera comb. n.) or absent (M. siamensis comb. n.); IDL setae 2–3 thick, armed with thick basal denticles. Limb II without soft setae; short seta on the exopod; scrapers not specialized, but with some denticles, especially on scrapers 6–8; gnathobase armed with four elements, filter comb armed with seven setae, of which two proximal are shorter than others. Limb III with six setae on the exopod, third and fourth setae long; distal endite armed with three setae and one sensillum; gnathobase with three elements, filter comb with seven setae. Limb IV relatively short, six setae on the exopod; third seta plumose, short, about two times shorter than the second seta; flaming-torch setae on the distal endite not modified; gnathobase armed with a setulated setae shorter than the length of endite itself, filter comb with five setae. Limb V relatively short, setae 3–4 of exopod subequal in length; filter comb reduced, with one short seta in M. dentifera comb. n. and none in M. siamensis comb. n.. Limb VI absent.
Adult male. Habitus smaller than female (Figure
The synapomorphies of Magnospina gen. n. are (1) basal spines longer than 2/3 of postabdominal claw, (2) presence of 1–4 large denticles, broad at their bases, protruding downwards, without setules between them. Magnospina gen. n. can also be differentiated from the genus Coronatella because it has a distinctive rounded angle at 1/3 of the length of the ventral margin, marginal setae of valves differentiated in three groups, setae from anterior group markedly longer, wide rostrum, postabdomen narrowing distally; the males of Coronatella do not bear two lateral aesthetascs on the antennules. Magnospina gen. n. differs from Anthalona in the presence of a distinctive rounded angle at 1/3 of the length of the ventral margin, sacks underneath lateral head pores (cosmaria) being absent, shape of postabdomen, poorly developed setules of the lateral fascicles, morphology of IDL (which does not have specialized denticles), and armature of limb I; the males of Anthalona also do not bear lateral aesthetascs on the antennules. The new genus differs from Karualona in the morphology of IDL setae, shape of the postabdomen, poorly developed setules of the lateral fascicles, seta on the exopod of limb II (present in Magnospina gen. n. and absent in Karualona) and endite basal of limb IV armed with three flaming-torch; the antennule of Karualona males bear just one lateral aesthetasc. Magnospina gen. n. is closer to Leberis according to
Magnospina dentifera comb. n., parthenogenetic female. 1habitus from Pantanal, Mato Grosso do Sul, Brazil 2habitus from São Paulo, Brazil 3–4habitus from San Pedro, Argentina parthenogenetic female adult from 5habitus, parthenogenetic female juvenile from San Pedro, Argentina 6 ventral margin of carapace from Distrito Federal, Brazil 7 denticles on the posteroventral margin of carapace. Scale bars: 50 µm.
Main differences and similarities between genera related to Coronatella-branch. To date, there is no description of males of Bergamina. From Karualona, only the male of K. iberica is known (see
Extremalona | Ovalona | Leberis | Celsinotum | Magnospina | Coronatella | Anthalona | Karualona | Bergamina | |
---|---|---|---|---|---|---|---|---|---|
Female characters | |||||||||
Maximum length | 0.5 | 0.35–0.7 | 0.5–1.1 | 0.53–0.9 | 0.32–0.48 | 0.25–0.6 | 0.3–04 | 0.4–0.45 | 0.68 |
Dorsal keel | absent | absent | present | present | absent | present in one species | absent | absent | absent |
Labral denticle | absente | absent | absent | absent | absent | present in one species | absent in three species | absent | absent |
Rostrum | rounded | rounded | truncated | truncated | rounded or truncated | rounded | rounded | rounded | rounded |
Main head pores | three connected | three connected, connection interrupted or absent | three connected | three connected | absent or three connected | three connected | two connected | two connected | three connected |
Lateral head pores | minute | minute, except in one species | minute | minute | absent or minute | minute | specialized, with underneath sacks | minute | minute |
A2 – spine on the apical segments | large | large | small | small | large | large | large | large | small |
Valves – ventral margin with a distinctive rounded angle | absent | absent | absent or slightly expressed | absent | present | absent | absent | absent | absent |
Valves – length of ventral setae from anterior group/posterior group | not differentiated | anterior longer than posterior | not differentiated | anterior shorter than posterior | anterior very longer than posterior | not differentiated | anterior longer than posterior in three species | anterior longer than posterior | not differentiated |
Valves – denticles | absent | 1–2 denticles in one species | absent | absent | 1–5 large denticles | 1–2 short denticles in two species | absent | short denticles in most species | absent |
PA – shape of postanal ventral margin | short, narrowing | short and rounded or elongated and narrow | elongated, narrowing | elongated, narrowing | elongated, narrowing | short, rounded | short, rounded | short, rounded | elongated, straight |
PA – basal spine | short | short | short | well-developed, shorter than 2/3 of postabdominal claw | well-developed, longer 2/3 of postabdominal claw | short | short | reduced or short | short |
PA – setae on the lateral fascicles | well- developed | well- developed | weakly developed | well- developed | weakly developed | well- developed | well- developed | well- developed | weakly developed |
P1 – IDL seta 1 | well- developed | well- developed | rudimentary | rudimentary | rudimentary or absent | rudimentary or absent | absent | well- developed | absent |
P1 – IDL setae 2–3 | with thin setules | with thin setules | with hard setules | with thin or hard setules | with basal denticles | with denticles or hard setules in one species | with denticles or thin setules in three species | with thin setules | with thin setules |
P1 – long anterior seta on endite 1 | absent | absent | absent | absent | absent | absent | absent | absent | present |
P2 – exopod seta | very short | short or moderated length | absent | absent | short | moderated length, rudimentary in two species | present in one species | absent | absent |
P3 – number of setae on the exopod | six | seven | six | six | six | six | six | six | six |
P4 – Number of flaming-torch | three | three | three | three | three | three | generally three, two in one species | two | three |
Male characters | |||||||||
A1 – lateral aesthetascs | six | two | two | two-six | two | absent | absent | one | unknown |
PA – dorsal and ventral margins | almost parallel | parallel or narrowing | narrowing | narrowing | narrowing | almost parallel | almost parallel | almost parallel | unknown |
PA – basal spine length | up 0.4 of postabdominal claw | absent or 0.5 of postabdominal claw | 0.2–0.5 of postabdominal claw | 0.1–0.3 of postabdominal claw | up 0.5 of postabdominal claw | 0.2–0.5 of postabdominal claw | 0.1–0.3 of postabdominal claw | 0.1 of postabdominal claw | unknown |
PA – position of gonopores | above of projection for claw insertion | above of projection for claw insertion | at base of postabdominal claw | above of projection for claw insertion or lateral | at base of postabdominal claw | above of projection for clauw insertion | above of projection for claw insertion | above of projection for claw insertion | unknown |
Alona dentifera (Sars, 1901):
Alona broaensis:
“neighborhood of São Paulo”, State of São Paulo, Brazil.
Lectotype: Parthenogenetic ♀, ZMOU F12341a, selected by D. Frey. Paralectotype: 5 parthenogenetic ♀♀, ZMOU F12341b; 1 parthenogenetic ♀ F12341c; 4 parthenogenetic ♀♀, I instar juvenile ♀, ZMOU F12386g; 2 instar II juvenile ♀ ZMOU F12386q; 2 partenogenetic ♀♀, instar II juvenile #, ZMOU, slide F9130; 6 parthenogenetic ♀♀ , ephippial ♀, ZMOU, slide F9131; 2 parthenogenetic ♀♀, ephippial ♀, ZMOU, slide F9131.
Nine parthenogenetic females and one adult male from Henrique pond, Brasília National Park, Distrito Federal, Brazil (15°41'18"S; 47°56'26.10"W), material collected by Grupo de Estudos de Ecossistemas Aquáticos (GEEA) in ix.2009 (FDRS048). One parthenogenetic female from Henrique pond, Brasília National Park, Distrito Federal, Brazil (15°41'16.5"S; 47°56'22.2"W), material collected by Lourdes M. A. Elmoor-Loureiro on 27.v.2002 (FDRS049). One parthenogenetic female from Cabocla II pond, Campo de Instrução de Formosa, Goiás, Brazil (15°48'21"S; 47°17'09.20"W), material collected by Grupo de Estudos de Ecossistemas Aquáticos (GEEA) on viii.2009 (FDRS050). Six adult parthenogenetic females and one juvenile from Baía da Célia, Fazenda Nhumirim (18°59'27.5"S, 56°39'41.0"W), Pantanal, Mato Grosso do Sul, Brazil, material collected on 07.ix.2000 by Valéria Barros. Four parthenogenetic females from Criminosa Pond (21°40'28.8"S, 57°53'28.5"W) identified as Alona broaensis, Porto Murtinho, Pantanal, Mato Grosso do Sul, Brazil, material collected on 19.i.2010, leg Adriana Maria Güntzel (FDRS054). Two parthenogenetic females from Coqueiral Pond, Paranapanema River, Angatuba, São Paulo, Brazil (23°29'22.64"S; 48°37'6.65"W). Material collected by Lourdes M. A. Elmoor-Loureiro on 30.v.2001 (CLLA063, 65-66). Two parthenogenetic females from Esquina, Middle Paraná River, Argentina (30°00.54'59"S; 59°32'51.93"W). Material collected by José Roberto Debastiani Júnior on 12.vi.2010 (FDRS052). Six parthenogenetic females from San Pedro, Lower Paraná River, Argentina (30°40'49"S; 59°18'48.80"W). Material collected by José Roberto Debastiani Júnior on 14.vi.2010 (FDRS053). Three parthenogenetic females from Pimenteira pond, Mata da Pimenteira State Park, Serra Talhada, Pernambuco, Brazil (7°53'48.96"S, 38°18'14.30"W). Material collected by Leidiane Pereira Diniz on 13.iv.2014 (FDRS407).
Magnospina dentifera comb. n. differs from Magnospina siamensis comb. n. because it has a rounded and wide rostrum and main and lateral head pores are absent in adult. Apical spines of the antenna about two times shorter than the apical segments. On the limbs, the main differences are: M. dentifera comb. n. bears a rudimentary seta 1 on the IDL, setae 2-3 of IDL armed with at least seven denticles and the presence of one seta on the filter comb of limb V.
Habitus ovoid, without dorsal keel, not compressed laterally, length 0.32–0.48 mm; eye and ocellus of different sizes. Head with rostrum wide, rounded, not pointed; head shield wide, with broadly rounded posterior margin, distance between mandibular articulations higher than length of its posterior portion, main head pores absent in adults, two or three connected main head pores in juveniles (Figures
Ephippial female. Not studied.
Adult male. Habitus smaller than female (Figure
Habitus ovoid, smaller than that in female, length about 0.35 mm, maximum height in the middle of the body (Figure
Neotropics, from Southern U.S.A to Argentina (
Alona siamensis:
Coronatella dentifera (Sars, 1901):
Rice field at Ban Bayao Baghe Sub-district, Phannanichom District, Sakhonnakhon Province, Thailand, 01.09.2004.
Holotype: parthenogenetic female,
Magnospina siamensis comb. n. differs from Magnospina dentifera comb. n. because it has a truncated rostrum, three connected main head pores, minute lateral head pores and a prominent sculpture on the carapace. Apical spines of the antenna are longer than the apical segments. On the limbs, the main differences are: IDL is armed with two setae (2-3), seta 2 with two thick basal denticles, seta 3 with one thick basal denticle, limb V without filter comb.
Female. According to the literature (
Habitus without dorsal keel, moderately compressed laterally, length 0.35–0.42 mm; eye and ocellus of subequal sizes. Head with rostrum wide, truncated; head shield ornamented with longitudinal lines, wide, posterior margin broadly rounded, distance between mandibular articulations higher than length of its posterior portion, three connected main head pores, lateral head pores minute. Labral keel wide, oval and naked, apex not elongated. Carapace covered with narrow longitudinal lines; ventral margin of carapace with a distinctive rounded angle at 1/3 of length; valves armed with 45 setae internally inserted at the ventral margin and differentiated in three groups, setae from anterior group markedly longer; posteroventral corner armed with 2–3 large denticles, broad at their bases, protruding downwards, without setules between them. Antennule do not exceed the tip of the rostrum, nine apical aesthetascs of different length which do not exceed the length of the antennular body. Antenna with formula of antennal setae 003/113, spines 101/001; first segment of endopod and exopod elongated; weak setules or spicules on the segments; spine on the first segment of the endopod longer than the second segment; apical spines longer than the apical segments. Postabdomen narrowing distally, length about 2.5 it is height; preanal angle prominent; postanal margin about 1.7–1.8 times longer than the anal margin armed with 3–4 single most distal denticles and 5 cluster of denticles; About 10 lateral fascicles with weak setules. Postabdominal claw inserted on the projection of postabdomen, longer than anal margin; base of claw armed with 1–2 long and strong spinules. Basal spine remarkably long, longer than 2/3 of postabdominal claw length, without spinules on the dorsal margin. Limb I with two thick setae (2–3) on the IDL (en 4), seta (2) with two thick basal denticles, seta (3) with one thick basal denticle; setae (1, a-c) on the endite 3 of subequal length, endite 3 without element; endite 2 armed with three setae (d-f), without element; endite 1 with three setae (g-i). Limb II without anterior soft setae; seta on the exopod short, not plumose; scrapers not specialized, but with some denticles, especially on scrapers 6–8; gnathobase armed with four elements, filter comb armed with seven setae, of which two are shorter than the others. Limb III with six setae on the exopod, third and fourth setae long; third seta slightly shorter than the second seta; distal endite armed with three setae and one sensillum; gnathobase with three elements, filter comb with seven setae. Limb IV relatively short, six setae on the exopod; setae 1–2 of similar lengths; flaming-torch setae on the distal endite not modified, setules on the first flaming-torch relatively longer that one observed in setae 2–3; gnathobase armed with a setulated seta shorter than length of endite itself, filter comb with five setae. Limb V with setae 3–4 of exopod similar in lengths; filter comb absent. Limb VI absent.
Ephippial female and male. Unknown.
Malysia, Thailand (Sinev 2007;
In the redescription of Alona dentifera,
The morphology of head shield, main head pores and of some structures of the limbs are different between M. dentifera comb. n. and M. siamensis comb. n.; however, analogous variation in these structures was already observed in Euryalona (
Recently,
The trend in morphological radiation in the clade Magnospina gen. n. concerns the external morphology but not to features of the trunk limbs (such as in the pulchella-group). It has been observed that a wide rostrum and the maintenance of primitive ovoid body shape, shared with other species-groups, possibly result from convergence or parallelism (
The morphology of the postabdomen is the most evident trait of Magnospina gen. n. in contrast to Leberis, Coronatella, Anthalona, Karualona, Extremalona, Bergamina, Celsinotum, Ovalona or Alona senso stricto; however, this morphological feature does not show a clear relationship with habitat and/or evolutionary history. Generally, specialized species have their morphology linked to habitat conditions (
Some studies observed that the male’s morphology is very important in making any inference about the relationship between closer species or between species groups in Aloninae (
When evaluating the morphology of species of the elegans-group from Palearctic zone,
The male of Ovalona genus also has two lateral aesthetascs on the antennules, but differs from Magnospina gen. n. because it has straight dorsal and ventral postabdominal margins, gonopores opening above projection to insertion of postabdominal claw, and setae 2–3 of IDL armed with setules. According to
Differently from Magnospina gen. n., males of the Coronatella genus have dorsal and ventral margins of the postabomen almost straight and lateral aesthetascs on antennules absent (
Alona broaensis species was described from Broa Reservoir, São Paulo, Brazil (
Magnospina gen. n. is one more genus derived from Alona sensu lato and belongs to the Coronatella-branch, being close to Leberis, as suggested by the phylogenetic analysis based on molecular data. The synapomorphies of the Magnospina gen. n. are: (1) basal spines longer than 2/3 of postabdominal claw, (2) presence of 1-4 large denticles, broad at their bases, protruding downwards, without setules between them. Magnospina gen. n. also has a wide rostrum, prominent preanal angle at postabdomen, setae 2-3 of IDL armed with basal denticles, six setae on limb III and limb VI absent. In addition to the female morphology presenting consistent differences when compared to other genera from the Coronatella-branch, the male features also support the creation of this new genus that includes M. dentifera comb. n. and M. siamensis comb. n.
We thank Prof. Dra. Adriana M. Güntzel (FUNDECT/MS), Dr. Jose Roberto Debastiani Junior and Biologist Lediane Pereira Diniz for providing the material of Alona broaensis from Pantanal and of Alona dentifera from Argentine and Pernambuco, respectively. We also thank Dr. Marcelo M. Dalosto for revising the English version of this manuscript. We are grateful to Dr. Eliana A. Panarelli, Dr. Gilmar Perbiche Neves and Dr. Ricardo Lourenço Pinto for the suggestions on the initial draft of this manuscript. We are deeply grateful to Dr. Alexey A. Kotov and Dr. Artem Yu. Sinev for the valuable criticisms, comments and suggestions that greatly improved this manuscript. The first author of this paper was awarded a grant from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).