Coronatella serratalhadensis, Sousa, Francisco Diogo Rocha, Elmoor-Loureiro, Lourdes Maria Abdu & Santos, Sandro, 2015

Sousa, Francisco Diogo Rocha, Elmoor-Loureiro, Lourdes Maria Abdu & Santos, Sandro, 2015, Redescription of Coronatella poppei (Richard, 1897) (Crustacea, Branchiopoda, Chydoridae) and a revision of the genus in Brazil, with descriptions of new taxa, Zootaxa 3955 (2), pp. 211-244 : 224-229

Coronatella serratalhadensis sp.nov.

( Figs. 7–8 ; 12)

Coronatella poppei in Soares & Elmoor-Loureiro (2011), p. 4; Diniz et al. (2013), p. 70.

Etymology. The name “ serratalhadensis ” refers to the type-locality of this species.

Type locality. A pond in Mata da Pimenteira State Park, Serra Talhada, Pernambuco, Brazil (7°53'48.96"S, 38°18'14.30"W).

Type material. Holotype. Undissected, adult parthenogenetic female from a pond in Mata da Pimenteira State Park, Serra Talhada, Pernambuco, Brazil (7°53'48.96"S, 38°18'14.30"W), in tube with 90% ethanol deposited at the Museum of Zoology of the University of São Paulo under access number MZUSP 32926. The label of the holotype is: “ Coronatella serratalhadensis sp. n., 1 parth. ♀ from to Pond in Mata da Pimenteira State Park, Serra Talhada, Pernambuco, Brazil. Holotype ”.

Paratypes. Eight slides containing dissected individuals deposited at Laboratório de Biodiversidade Aquática, Universidade Católica de Brasília ( CLLA 050 to CLLA 057). This material was collected by Leidiane Diniz on 21.x.2011.

Other Material Examined. Four adult parthenogenetic females from the Saco I reservoir, Serra Talhada, Pernambuco, Brazil (7°24'43"S, 35°10'74"W), material collected by Marcos Felipe Menezes Magalhães on 11.xi.2011. Two adult parthenogenetic females and two juveniles from the pool in Casa Forte Square, Recife, Pernambuco, Brazil (15° 46' 59"S, 47° 50' 53"W), material collected by Lourdes M. A. Elmoor-Loureiro on 04.iii.1981 (EL02018).

Diagnosis. Female. Animal small-sized, length 0.27–0.36 mm. Head with rostrum short, blunt, projected downward, ocellus as large as eye, lateral head pores tiny. Carapace without dorsal keel, presenting lateral compression with 8–13 longitudinal lines, 28–38 ventral setae, posterior ventral corner without denticles and armed with spinules arranged in three groups presenting 8–10 spinules. Antennules with sensory seta about 1.7 times smaller than antennular body. Antenna with second exopodite segment presenting one row of long setules, atennal formula: spines 001/101, setae 113/003, apical spines of different length. Postabdomen relatively long, lateral fascicles arranged in 5–6 groups, 5–6 clusters of marginal denticles. Terminal claw about 1.5 times longer than anal margin and with one row of short spinules on base. Basal spine about 2.6 times as long as width of terminal claw at its base and with setules on the dorsal margin. Limb I: with ODL seta about same length as the longest IDL seta, accessory seta relatively short, IDL armed with setae 2+1, longest setae with strong proximal spines, third endite with inner setae longer than the other two setae. Limb II: with seta on exopodite, scrapers 6–8 of similar length and armed with strong denticles, filter comb with seven setae. Limb III: exopodite with six setae, seta 3 about 2.6 times longer than fifth seta, seta 6 naked and about 2.6 times shorter than fifth seta, distal endite presenting one sensillum. Limb IV: exopodite with six setae, fourth seta about 2.3 times shorter than fifth seta. Limb V: with exopodite without depression on marginal line, setae of inner lobe of different size, one long and inflated element inserted behind the inner setae present. Gnathobase with one short element, filter comb absent. Male. Unknown.

Description. Parthenogenetic female. Habitus ( Fig. 7 A–C; 12F). Animal small-sized, length 0.27–0.36 mm, about 1.5 times as long as high.

Head ( Fig. 7 A–C). Ocellus as large as eye. Rostrum short, blunt, projected downward. Three main head pores of similar size connected by narrow connection, IP about 1.6 times longer than PP. Lateral head pores tiny, at level of median pore or inserted between proximal and median pores. Head shield ( Fig. 7 G–I). With anterior margin rounded, mandibular articulation inserted at median portion.

Labrum ( Fig. 2 E). Labral keel wide in lateral view, moderately convex, naked; apex with variable morphology, rounded or presenting projecting towards anterior.

Carapace ( Fig. 7 D–F; 12G). Presenting lateral compression, colorless and transparent; dorsal keel absent; carapace striated with eight-13 longitudinal lines; ventral margin slightly concave near to median portion, with 28– 38 setae, proximal and distal group longer than median group; short spinules present between ventral setae; ventral setae followed by spinules arranged in at least three groups, each presenting 8–10 spinules projected beyond margin; last spinules of the each group thick. Posterior ventral corner without denticles. Posterior lines of valve may present weak waviness.

Antennules ( Fig. 7 M). Exceeding tip of rostrum, about two times longer than wide, three rows of setulae of similar length on antennular body. Antennular sensory seta slender, about 1.7 times smaller than antennular body, inserted at two-thirds of antennular length. Nine terminal aesthetascs of different size not exceeding the length of the antennular body.

Antenna ( Fig. 7 N–O). Coxal setae of similar length, slightly setulated. Basipodite thick, with one row of setulae and one spine. First exopodite segment naked. Second exopodite segment presenting a group of three relatively long setulae and inserted on terminal portion of segment. Segments of endopodite naked. Antennal formula: spines 001/101; setae 113/003. Seta on the first exopodite segment short, slightly exceeding the length of the last segment; seta on the second segment bi-segmented and densely setulated. Spine on the first segment of the endopodite naked, thick, long, exceeding the length of the second segment, reaching the mid-length of third segment. Apical spines of different length, naked. Apical setae bi-segmented and densely setulated.

Thorax about 2.5 times longer than abdomen ( Fig. 7 A–C). Abdomen presenting 1–2 rows of setae.

Postabdomen ( Fig. 7 P–R; 12H) relatively wide, about 1.6 times as long as wide; ventral margin relatively straight. Rows of spinules on the ventral margin were not observed. Pre-anal margin longer than anal and postanal margin. Anal margin ranging from slightly concave to straight, armed with at least three groups of spinules and four lateral fascicles; anal and postanal corners not well marked. Postanal margin rounded and massive, lateral fascicles arranged in 5–6 groups with up to 18 long setules; at least three fascicles exceeding the margin of the postabdomen; 5–6 clusters of 2–4 marginal denticles, proximalmost one presenting more denticles than the others. Terminal claw ( Fig. 7 P–R; 12I) implanted at short projected basis from the postabdomen, about 1.5 times longer than anal margin, thick, uniformly curved, with a row of short spinules on base. Two pecten present. Basal spine short in comparison to terminal claw, about 2.6 times as long as width of terminal claw at its base, armed with setules on the dorsal margin.

Mandibles ( Fig. 7 S). Well developed in relation to body size.

First maxilla ( Fig. 8 A). Armed with two setae densely setulated.

Five pairs of limbs.

Limb I ( Fig. 8 B–D). Epipodite not studied. ODL with thin seta, serrulated from to median portion, about same length as the longest IDL seta; accessory seta relatively short, plumose. IDL with three groups of spinules on its face, setae armed in 2+1, two longest setae of similar size; setae armed with strong proximal spines; distalmost spines as thin denticles. Third endite with four setae relatively robust; inner setae setulated (a–b), longer than the two others. Second endite with one row of strong spinules: three setae of different length (d–f); seta 5 (e) about 1.2 times longer than seta 4 (f) and about 3.2 times longer than seta 6 (d); setae 4–5 (e–f) with thick spinules on lateral face; seta 5 (e) with spinules inserted on median portion; seta 6 (d) about two times shorter than seta 4 (f). First endite with three marginal setae (g–i), setae 2–3 (g–h) bi-segmented and of similar length. No specialized elements on endites. Ejector hooks of similar length. Ventral face of limb with six rows of setulae organized in clusters, decreasing in length toward distal portion. Gnathobase thin, with distal portion densely setulated.

Limb II ( Fig. 8 E–F). Exopodite elongated and distally setulated. Seta on exopodite present, plumose, about 1.6 times smaller than the exopodite itself. Endite armed with eight scrapers, scraper 6 markedly denticulated, without accessory seta near scraper 1; scraper 1 slightly longer than scraper 2; scraper 3–5 of similar length, armed with thick denticles; scraper 7–8 short, armed with thick denticles. Proximal portion of gnathobase short, wide and densely setulated; distal portion armed with three elements and one sensillum; first element with sharp apex. Filter comb armed with seven setae setulated from median portion; setae 1–2 remarkably shorter than other setae.

Limb III ( Fig. 8 G–J). Pre-epipodite not studied. Epipodite oval without projection. Exopodite subquadrangular with six marginal setae arranged in 2+4: setae 1–2 of different length; seta 3 bi-segmented, setulated, about 2.6 times longer than fifth seta; fourth seta short and thick; sixth seta naked, about 2.6 times shorter than fifth seta. Distal endite with three setae (1’–3’): two scraper-like of similar length (1’–2’), sensillum present between them; third seta slightly geniculated, densely and bilaterally armed with setules (3’). Basal endite armed with four plumose setae increasing in length towards the gnathobase; four soft setae of similar length present. Gnathobase with four elements: first as a robust and cylindrical sensillum; second a geniculated seta with a group of setulae on its base and distally setulated; third and fourth elements naked, with acute tip. Filter comb armed with seven long setae.

Limb IV ( Fig. 8 K–M). Pre-epipodite subquadrangular and setulated, epipodite rectangular with short projection. Exopodite rounded with six plumose marginal setae: setae 1–2 of similar length; fourth seta about 2.3 times shorter than fifth seta and 1.6 times shorter than sixth seta. Distal endite with four setae (1’–4’), one scraperlike (1’), three flaming-torch-like decreasing in length towards the base (2’–4’); first flaming-torch thick, similar in length to scraper-like seta. Basal endite armed with three soft setae increasing in length towards the base. Gnathobase armed with one long and cylindrical sensillium and a long seta inserted on robust and naked base. Filter comb armed with five setulated setae.

Limb V ( Fig. 8 N). Pre-epipodite subquadrangular and densely setulated, epipodite rectangular with short projection. Exopodite oval, not divided in lobes, about twice as long as wide; marginal line between setae 3–4 densely setulated; four plumose marginal setae decreasing in length; third seta about 1.8 times shorter than first seta; fourth seta about 2.7 times shorter than third seta. Internal lobe wide, oval and with long terminal setules; two setulated setae of different size on inner face of the lobe; one long and inflated element inserted behind of the inner setae. Gnathobase reduced, with a short element. Filter comb absent.

Male. Unknown.

Ephippial female. Unknown.

Differential diagnosis. Coronatella serratalhadensis sp.nov. is distinguished from other species of the genus because of its spinules on the posteroventral carapace margin, organized into groups. In general features, C. serratalhadensis sp.nov. resembles C. circumfimbriata Megard, 1967 , which can be differentiated in number of denticles of postabdomen (5–6 in C. serratalhadensis sp.nov. and 6–8 in C. circumfimbriata ) and fine morphological traits from the thoracic limbs: C. serratalhadensis sp.nov. has long setae on the third endite of Limb I, IDL setae armed in 2+1, sensillum on gnathobase of Limb II, Limb III with four elements on the gnathobase and inner setae without sensillum, Limb IV with first flaming-torch of similar size to scraper-like seta, inner portion of Limb V armed with two elements. Recently, Kotov et al. (2010) discovered a similar species from the Chilean Andes (not yet described) to C. circumfimbriata , but it presents long and thin setules on the base of the terminal claw of the postabdomen. This morphological trait is not observed in C. circumfimbriata and C. serratalhadensis sp.nov. The main differences between C. serratalhadensis sp.nov. and other Brazilian species of Coronatella may be observed in Table 1.

Distribution and biology. So far, C. serratalhadensis sp.nov. possesses a very narrow distribution, being found only in the state of Pernambuco, northeastern Brazil ( Fig. 13 ). This species seems to be associated with small and shallow water bodies, including artificial environments.

Figures

FIGURE 2. Coronatella poppei (Richard, 1897) from Limache, Chile. A – I parthenogenetic female. A, habitus, lateral view. B, posteroventral corner of carapace. C – D, head pores. E, labral keel. F, antennule. G, antenna. H – I, postabdomen. J – M Male. J, habitus. K, head pores. L, antennule. M, postabdomen. scale bars = 100 µm.

FIGURE 7. Coronatella serratalhadensis sp. nov.. A – C, habitus, lateral view. D, carapace. E, posteroventral corner of carapace. F, idem. G, head pores. H, idem. I, head shield. J – L, labral keel. M, antennule. N, antenna. O, idem — coaxal setae. P – R, postabdomen. Scale bars = 100 µm.

FIGURE 8. Coronatella serratalhadensis sp. nov.. A, maxillule. B, limb I. C, idem — gnathobase. D, idem — ODL and IDL. E, limb II. F, idem — exopodite. G, limb III, exopodite. H, idem — endite. I, idem — endite, internal setae. J, idem — elements of gnathobase. K, limb IV, exopodite. L, idem — endite. M, idem — gnathobase. N, limb V, arrow showing one element on the gnathobase. For abbreviations, see Material and methods. Scale bars = 50 µm.

FIGURE 13. Geographical distribution of Coronatella species in the Neotropics. Specifically for Brazil, the map presents the delimitation of hydrographic Regions according to Resoltution 32 from Conselho Nacional de Recursos Hídricos. 1 Amazônica; 2 Tocantins / Araguaia; 3 Atlântico Nordeste Ocidental; 4 Parnaíba; 5 Nordeste oriental; 6 Paraguai; 7 São Francisco; 8 Atlântico leste; 9 Paraná; 10 Uruguai; 11 Atlântico sul; 12 Atlântico sudeste. Coronatella monacantha is widely distributed in the Neotropics. Coronatella poppei seems to be restricted to the meridional part of South America. Coronatella paulinae sp. nov., until this moment, shows distribution in the central part of Brazil. Coronatella serratalhadensis sp. nov. and C. undata sp. nov. occur in the Brazilian Northeast; however, C. undata sp. nov. seems to be restricted to environments closer to the coast.