Elpidium higutiae, Pereira & Rocha & Martens & Pinto, 2023

Pereira, Julia S., Rocha, Carlos E. F., Martens, Koen & Pinto, Ricardo L., 2023, Six new species of Elpidium Müller, 1880 (Podocopida: Limnocytheridae) from Eastern Brazil, Zootaxa 5258 (1), pp. 1-38 : 24-30

Elpidium higutiae n. sp.

Figs. 16–19

urn:lsid:zoobank.org:act:6062AAC3-1E5D-4D9F-B153-FA01290C295A

Diagnosis. Carapace medium-sized (length of male = 818 µm; length of female = 872 µm) and elongated (width/ length ratio = 0.7; height/length ratio = 0.5). Surface brownish with sparse setae and normal pore canals. Left valve overlapping right one. Sexual dimorphism marked: posterior contour in dorsal view narrowly rounded in males, truncate in females. Ventral surface flat in central portion. In dorsal and ventral views, carapace symmetric. In right lateral view, external flange subtle, dorsal margin arched, ventral margin nearly straight. Hinge bar long (slightly longer than 2/3 of length of dorsal margin); posterior proto-tooth slightly more developed than anterior one. Cop without differentiation of distal glans and ejaculatory duct, long and sinuous, with straight and thin apex. LR short, with simple, curved shape. DL short (basis width/distal lobe length ratio = 0.62) with acuminate apex and pointed ventro-basal digital expansion of medium-length.

Etymology. The specific epithet “higutiae” is in honor of prof. Janet Higuti for her contribution to the freshwater ostracod research field and also to recent studies dealing with Elpidium .

Type Material. Holotype: a dissected male ( MZUSP 40363 ) with valves dried and coated for scanning electron microscopy stored in a micropaleontological slide and appendages mounted in a sealed slide with glycerin.

Allotype: a dissected female ( MZUSP 40364 ) stored like the holotype.

Paratypes: three males ( MZUSP 40365 , MZUSP 40366 , MZUSP 40370 ) and a female

( MZUSP 40374) dissected and stored like the holotype; three males ( MZUSP 40369 , MZUSP 40368 , MZUSP 40367 ) and three females ( MZUSP 40373 , MZUSP 40372 , MZUSP 40371 ) dried and coated for scanning electron microscopy stored in micropaleontological slides .

Type Locality. Tank-bromeliads from Parque Estadual de Campos do Jord„o, Campos do Jord„o, S„o Paulo, Brazil. Approximated geographic coordinates: 22º41′36.2″ S, 45º27′35.0″ W. Material collected on Feb. 21, 2003, by Ricardo L. Pinto and Zélio S. Silva (Instituto de Biociências, Universidade de S„o Paulo).

Description of the male.

Measurements. L: 818 µm; W: 586 µm; H: 450 µm.

Carapace ( Fig. 16A–C ). Medium-sized (L = 818 µm) and relatively elongated. Surface with sparse setae and normal pore canals. In dorsal and ventral views, posterior contour narrowly rounded, carapace symmetric. In dorsal view, anterior end slightly acuminated. In ventral view, surface flat on central portion. In right lateral view, carapace elongated and left valve overlapping right one along anterior, dorsal and posterior margins; dorsal margin rounded and slightly arched; ventral margin nearly straight; posterior margin evenly rounded and anterior margin pointed with slightly external flange on antero-ventral portion.

Left valve ( Fig. 16D–F ). In internal view with flange narrow along anterior, ventral and posterior margins, discontinued by bow funnel-shaped structure. Selvage weakly marked and forming bow funnel-shaped structure in oral region. Calcified inner lamella and vestibule present on both anterior and posterior regions, posterior narrower than anterior one and with inner list.

Right valve ( Fig. 16G–I ). In internal view, with flange greatly evident from anterior to posterior regions; with sparse pseudochaetae postero-ventrally. Selvage well marked from anterior region to posterior proto-teeth, forming bow funnel-shaped structure in oral region. Calcified inner lamella and vestibule present on anterior and posterior regions, posterior one narrower and with inner list. Hinge bar long (slightly longer than 2/3 of length of dorsal margin) and thin, with posterior proto-tooth slightly more developed that anterior one.

Hemipenis ( Fig. 18D ). With broad, rounded and sclerotized muscular body.Main appendage elements:copulatory complex (cop plus LR) and DL; cop hook-like, long and sinuous, with straight and thin apex. LR short, with simple, curved shape. DL short and small (basis width/distal lobe length ratio = 0.62) with acuminate apex and basal digital expansion of medium-length; ds thin, medium-sized; fl with pair of setae and numerous pseudochaetae.

Other appendages as in Elpidium oxumae n. sp. ( Figs. 17A, B, D, E , 18A–C ).

Description of female.

Measurements. L: 872 µm; W: 659 µm; H: 482 µm.

Carapace ( Fig. 19 ). Medium-sized (L = 872 µm). Sexual dimorphism marked: females with major width displaced posteriorly due to brooding chamber and posterior contour truncate in dorsal view. In dorsal and ventral views, carapace symmetric. In right lateral view, carapace rather elongated, left valve overlapping right one along anterior, dorsal and posterior margins; dorsal margin arched; ventral margin nearly straight.

Antenna, terminal segment ( Fig. 17C ). Similar to equivalent in males, but terminal segment with vestigial seta, hyaline formation and three biserrate claws instead of two biserrate and one pectinate claws.

Abdomen ( Fig. 18E ). Female end of body rounded and large with spine-like seta, genital lobes and furcal lobes. Spine-like seta stiff, in dorso-medial position; gl rounded, rigid with trabeculae internally; fl rounded but not rigid, with three equal-length pappose setae and numerous pseudochaetae.

Other appendages as in Elpidium oxumae n. sp. ( Figs. 17A, D, E , 18A–C ).

Differential diagnosis. Elpidium higutiae n. sp. resembles the type species E. bromeliarum in terms of the sexual dimorphism of the carapace. However, E. higutiae n. sp. is more elongated: height/length for both males and females for E. higutiae n. sp. is 0.55, while it is 0.61 for E. bromeliarum . The hemipenis cop of E. higutiae n. sp. is not the short hook-like type found in E. bromeliarum but rather a long and sinuous hook with thin and straight apex. The LR of E. higutiae n. sp. is also different and reminds the one described above for E. eriocaularum n. sp., but without the globular shape on its basis. DL vaguely reminds the one observed in E. littlei , specially by the reduced size. However, the DL of E. higutiae n. sp. has an acuminate (instead of a rounded) apex and a pointed digital expansion, which is absent in E. littlei .

Distribution. The species is currently known solely from tank-bromeliads in the type locality.

Figures

FIGURE 16. Elpidium higutiae n. sp., male, carapace.A—dorsal view (paratype, MZUSP 40367); B—ventral view (paratype, MZUSP 40368); C—right lateral view (paratype, MZUSP 40369); D—left valve, internal view (holotype, MZUSP 40363); E—left valve, internal view, detail of antero-ventral region (holotype, MZUSP 40363); F—left valve, internal view, detail of postero-ventral region (holotype, MZUSP 40363); G—right valve, internal view (holotype, MZUSP 40363); H—right valve, internal view, detail of antero-ventral region (holotype, MZUSP 40363); I—right valve, internal view, detail of postero-ventral region (holotype, MZUSP 40363). Scale bars: A–D, G—200 µm; E, F, H, I—100 µm.

FIGURE 17. Elpidium higutiae n. sp., A, B, D, E, male, C, female, appendages.A—antennula (holotype, MZUSP 40363); B— antenna (holotype, MZUSP 40363); C—antenna, terminal segment (allotype, MZUSP 40364); D—mandible, coxa (paratype, MZUSP 40365); E—maxillula (holotype, MZUSP 40363). Scale bars: A, B, D, E—0.1 mm; C—0.03 mm.

FIGURE 18. Elpidium higutiae n. sp., A–D, male, E, female, appendages. A—first thoracic limb (holotype, MZUSP 40363); B—second thoracic limb (holotype, MZUSP 40363); C—third thoracic limb (holotype, MZUSP 40363); D—hemipenis (paratype, MZUSP 40366); E—abdomen (allotype, MZUSP 40364). Scale bars: A–C—0.1 mm; D, E—0.2 mm.

FIGURE 19. Elpidium higutiae n. sp., female, carapace.A—dorsal view (paratype, MZUSP 40371); B—ventral view (paratype, MZUSP 40372); C—right lateral view (paratype, MZUSP 40373); D—left valve, internal view (allotype, MZUSP 40364); E—left valve, internal view, detail of antero-ventral region (allotype, MZUSP 40364); F—left valve, internal view, detail of postero-ventral region (allotype, MZUSP 40364); G—right valve, internal view (allotype, MZUSP 40364); H—right valve, internal view, detail of antero-ventral region (allotype, MZUSP 40364); I—right valve, internal view, detail of postero-ventral view (allotype, MZUSP 40364). Scale bars: A–D, G—200 µm; E, F, H, I—100 µm.