Eurycercus (Bullatifrons) dumonti, Bekker & Kotov & Elmoor-Loureiro, 2010

Bekker, Eugeniya I., Kotov, Alexey A. & Elmoor-Loureiro, Lourdes M. A., 2010, The genus Eurycercus Baird, 1843 (Cladocera: Eurycercidae) in the Neotropics, Journal of Natural History 44 (41 - 42), pp. 2481-2508 : 2495-2498

publication ID	https://doi.org/ 10.1080/00222933.2010.488752
persistent identifier	https://treatment.plazi.org/id/03D887D2-EF10-8731-C9BF-FE4CFCCA5998
treatment provided by	Felipe
scientific name	Eurycercus (Bullatifrons) dumonti
status	sp. nov.

Treatment

Eurycercus (Bullatifrons) dumonti View in CoL sp. nov.

( Figures 8–11 View Figure 8 View Figure 9 View Figure 10 View Figure 11 )

Etymology

This species is dedicated to Professor Henri J. Dumont, renowned Belgian investigator of the Cladocera and other freshwater animals, who collected the type series.

Type locality

Lake Regadera near Bogotá, Columbia. Co-ordinates: 4.4000° S, 74.1500° W GoogleMaps .

Type material

Holotype. Adult parthenogenetic female in 96% alcohol, MGU ML 97 . Label of the holotype: “ Eurycercus (Bullatifrons) dumonti sp.nov., 1 parth. ♀ from Lake Regadera near Bogota, Columbia, coll. in 16.09.1992 by H.J. Dumont, HOLOTYPE ”.

Paratypes. Fifteen females, MGU ML 98 ; 10 females , AAK 2009-075 .

No hydrochemical information was taken during sampling. Lake Regadera (Ebmolsa la Regadera) is a large, shallow, artificial water reservoir in the water system serving Bogota town, suffering from high anthropogenic pressure, i.e. organic pollution.

Other material studied

Eleven parthenogenetic females from Lagoa dos Patos, connected to Rio Invinhema, Paraná floodplain, Mato Grosso do Sul, Brazil, coll. in September 1992 by F. A. Lansac-Tôha. Coordinates: 22°49′33.66″ S, 53°33′09.9″ W GoogleMaps .

Lagoa dos Patos is a small lagoon (c. 1.2 km 2), with depths ranging between 2.8 and 4.8 m, and connected by a permanent channel with Invinhema River, at the upper Paraná River floodplain; dense stands of aquatic macrophytes are present, particularly of the genera Eichhornia , Salvinia and Polygonum ( Serafim-Junior et al. 2003) . Rodrigues et al. (2002) have investigated the limnological parameters of Patos Lagoon, such as: dissolved oxygen (1.0–9.0 mg/l), pH (c. 5.8–7.5), conductivity (c. 20–50 µS/cm), total nitrogen (c. 250–1300 mg /l), total phosphorus (c. 10–90 µg/l). The climate of the region is subtropical humid or type Cfa, according to the Köppen classification; the mean annual rainfall is 1500 mm, and the mean temperature is below 18°C in winter, with rare frosts, and above 22°C during warmer months ( Souza et al. 2009).

Diagnosis

Dorsal margin with a dorsal bubble bearing head pores. In anterior view, body wide, median dorsal keel absent. Rostrum short; posterior portion of head shield lacking a straight section of the margin immediately anterior to the point of mandibular articulation; lateral head pores ovoid. Labrum with a small, rounded median keel. Postabdomen with a shallow distal anal embayment and 80–93 preanal teeth. Teeth at base of preclaw portion long, thin, predominantly single. Antenna I protruding greatly beyond labral keel and tip of rostrum; elongated; antennular sensory seta arising approximately in its middle; denticles in rows encircling antennular surface specially small, located on clearly visible ridges. IDL of limb I with three bisegmented setae, among them, a remarkable strong hook-like seta, but not as large as in E. macracanthus . IDL supplied with seven or eight long distal spinules, seven to nine long proximal spinules, six to eight long marginal spinules and seven to nine short basal spinules. Limb II scraper 5 with 20–21 denticles, scraper 6 with 20–26 denticles, scraper 7 with 20–24 denticles. Nine setae in filter plate III; eight setae in filter plate IV, eight setae in filter plate V. Intestine has a single loop. Length 0.65–1.59 mm.

Short description

Adult parthenogenetic female. In lateral view body subovoid in larger females (BH/ BL = 0.61–0.64) ( Figure 8A View Figure 8 ). Dorsal margin interrupted by a dorsal bubble bearing head pores. In anterior view, body wide, not compressed laterally, median dorsal keel is absent ( Figure 8B View Figure 8 ). Parthenogenetic females carry few eggs in the brood pouch. Head with short rostrum ( Figure 8C,D View Figure 8 ). Head shield little wider than long (HW/HL about 1.1) with maximum height posterior to level of mandibular articulation, posterior portion lacking a straight section of the margin immediately anterior to the point of mandibular articulation ( Figure 8E View Figure 8 ). A single major “head pore” as a ringed, suboval field of special cuticle; a minute, circular lateral pore located at either side of major pore, closer to it ( Figure 8F View Figure 8 ). Labrum with a small, rounded median keel ( Figure 8C–D,G–I View Figure 8 ). Armature of posterior valve margin as in previous species ( Figure 8J–L View Figure 8 ). Postabdomen broad ( PH /PL about 0.50–0.55), with subparallel dorsal and ventral margins ( Figure 9A View Figure 9 ). Distal anal embayment shallow ( Figure 9C,D View Figure 9 ). Armature of the preanal margin as a series of preanal teeth (NT = 80–93); small gap lacking any teeth at base of postabdominal setae ( Figure 9B View Figure 9 ); teeth in middle of preanal margin with sharp tips. Teeth at base of preclaw portion long, thin, predominantly single, while longer distalmost teeth doubled or tripled ( Figure 9E,F View Figure 9 ). Postabdominal claw robust (CL/PL about 0.3); first (distalmost) basal spine long (DS/CL about 0.3), second (basalmost) spine short (BS/CL about 0.16; BS/DS about 0.4–0.5). Antenna I short relative to body length (AL/BL about 0.12), but protruding greatly beyond labral keel and tip of rostrum; elongated (AL/DA = 3.1–3.5) ( Figure 10A,B View Figure 10 ), triangular in section ( Figure 10C View Figure 10 ). Antennular sensory seta arising approximately in its middle. Denticles in rows encircling antennular surface specially small, located on clearly visible ridges. On antenna II, spine situated on basal segment of exopod somewhat shorter than length of second segment ( Figure 10D,E View Figure 10 ). In general, limbs are very similar to those in the previous species. Limb I with IDL supplied with three bisegmented setae generally decreasing in size towards endites, among them, a remarkable strong hook-like seta, but not as large as in E. macracanthus . IDL supplied with four groups of spinules, namely: seven or eight long distal spinules, seven to nine long proximal spinules, six to eight long marginal spinules and seven to nine short basal spinules ( Figure 10F,G View Figure 10 ). Limb II scraper 5 with 20–21 denticles, scraper 6 with 20–26 denticles, scraper 7 with 20–24 denticles. Other limbs as in previous species. Intestine has a single loop. Length 0.65–1.59 mm.

Comments on juvenile female. In contrast to adult female, body more rectangular, somewhat lower (BH/BL = 0.57–0.62), dorsal margin almost straight ( Figure 11A View Figure 11 ). Labrum as adult ( Figure 11B View Figure 11 ), but rostrum a little shorter. Lateral head pores located close to major pore ( Figure 11C View Figure 11 ). Postabdomen with significantly fewer preanal teeth (NT = 72–81), fewer postanal teeth and more robust claws with relatively large first (distalmost) basal spine ( Figure 11D View Figure 11 ). Antenna I shorter than in adult ( Figure 11B View Figure 11 ). IDL with four to six long distal spinules, five or six long proximal spinules, five or six long marginal spinules and five long basal spinules ( Figure 11E,F View Figure 11 ). Limb II scraper 5 with 20–23 denticles, scraper 6 with 18–24 denticles, scraper 7 with 14–20 denticles.

Differential diagnosis

See Table 1 and Discussion for differentiation of American species of Eurycercus (Bullatifrons) .

Distribution

The species is known from the Andean highlands (Lake Regadera), Columbia and the lowlands in southern (subtropical) Brazil (Estado do Mato Grosso do Sul). It is probably widely distributed on the South American continent.