Rivudiva naia, Cruz & Boldrini & De Lima & Hamada, 2022

Cruz, Paulo Vilela, Boldrini, Rafael, De Lima, Cláudia R. T. & Hamada, Neusa, 2022, It is a mess! How many species are in Rivudiva trichobasis Lugo- Ortiz & McCafferty, 1998 (Ephemeroptera: Baetidae)?, European Journal of Taxonomy 789 (1), pp. 153-191 : 179-184

Rivudiva naia sp. nov.

urn:lsid:zoobank.org:act:FC398BC7-7504-4F40-AF67-9479BABF0926

Figs 16–18

Diagnosis

NYMPH. The combination of the characters: 1) labrum distal margin straight ( Fig. 16A ); 2) labrum ventral surface with simple or pectinated robust setae on distal margin ( Fig. 16A ); 3) left mandible with incisors fused at basal third ( Fig. 16B ); 4) maxillary palp segment II with large apical lobe ( Fig. 16D ); 5) superlingua with truncate outer margin ( Fig. 16F ); 6) outer arc of robust setae of glossa close to margin, slightly removed from distal margin ( Fig. 16G ); 7) labial palp segment III conical, apex broad pointed ( Fig. 16G ); 8) dorsal and ventral margin of forefemur with one row of long spine-setae from base to apex ( Fig. 17A ); 9) forefemur on anterior surface with short blunt setae at middle ( Fig. 17A ); 10) patella-tibial suture present; 11) distal margin of terga with wide spines (18A).

Etymology

ʻ Naia ʼ in Amazonian folklore is the name of the native woman that, after being drowned by the enchantment of the god Moon, was transformed into a water star – Victoria Regia (Victoria amazonica (Poepp.) J.C.Sowerby). For this reason, the fragrant whitish flowers of this plant only open at night. Name in apposition.

Material examined

Holotype BRAZIL • nymph on slide; Roraima, Mucajaí, Apiaú, waterfall Esmeralda ; 02°29′42.76″ N, 61°23′41.61″ W; 14 Feb. 2021; R. Boldrini leg.; sand; UFRR.

Paratypes BRAZIL • 1 nymph; same collection data as for holotype; UFRR • 1 nymph; same collection data as for holotype; UFV • 1 nymph; same collection data as for holotype; INPA .

Description

Nymph

LENGTH. Body, 4.1–4.9 mm.

HEAD.Antenna. Flagellum with minute spines on apex of each segment. Labrum ( Fig. 16A ). Rectangular, length about 0.6× maximum width; distal margin straight, one row of robust, eventually pectinated, setae from lateral to middle of distal margin; one row of thin bifid setae on distal margin not reaching distolateral margin; dorsal surface, near distal margin, with many thin setae over surface. Left mandible ( Fig. 16B ). Incisors partially cleft in two sets (fused at basal third); outer and inner set of incisors respectively with 4 + 3 denticles; prostheca robust; margin between prostheca and mola straight; tuft of spine-like setae at base of mola absent; subtriangular process wide; denticles of mola not constricted; mola with two large denticles, inner larger than outer; outer margin convex. Right mandible ( Fig. 16C ). Incisors fused at base; outer and inner set of incisors respectively with 3 + 2 denticles and outer incisor with spine-like process; prostheca stout, bifurcated at base, inner lobe longer than outer; margin between prostheca and mola straight; tuft of spine-like setae at base of mola present; denticles of mola not constricted; apex of mola with one simple seta; first process of mola triangular, second expanded and straight; outer margin convex. Maxilla ( Figs 16D ). Maxillary palp 1.8× length of galea-lacinia; segment II 1.2× length of segment I; segment II inner margin with large apical lobe; ventral canine enlarged, not laterally expanded; set of distal setae of the inner-ventral row pointed. Hypopharynx ( Fig. 16E ). Lingua longer than superlingua, sub-quadrangular with a small distomedial projection covered by tuft of simple setae; superlingua with truncate outer margin; short, thin, simple setae scattered over distal margin of lingua and superlingua. Labium ( Fig. 16F–G ). Glossa slightly expanded at base, distally rounded, shorter than paraglossa; ventral surface covered by thin setae; dorsal surface with inner arc with setae following inner-distal margin, outer arc at base following outer margin, slightly far from distal margin. Paraglossa curved inward; apex with one row of robust and long spine-like setae; outer margin with four long thin setae; dorsal surface with four longitudinal rows of setae, first near inner margin longer than two third of length, distally with long robust setae and basally with long thinner setae; second with third of length of inner row, with robust long setae; and third with same length as second, distal setae long and robust, basal setae long and thin; ventral surface with one row of five setae near to ventral margin. Labial palp with segment I 0.8× length of segments II and III combined; inner distal protuberance of segment II rounded and projected to apex, covered with thin setae; segment III conical, apex broad pointed; outer margin with short thin setae, dorsal surface with one row of short spine-like setae near inner margin, ventral surface with one row of thin setae.

THORAX. One mark on mesothorax. Foreleg ( Fig. 17A–C ). Femur length about 2.9× maximum width; dorsal and ventral margin with one row of long spine-like setae; anterior surface with one medial row of short setae, one row of blunt setae near dorsal margin not reaching apex; posterior surface with one row of long spine-like setae near ventral margin reaching apex, and one medial row of long spine-like setae. Tibia. Dorsally bare; ventral margin with one row of long spine-like setae; patella-tibial suture present. Tarsus. Ventral margin with one row of spine-like setae. Tarsal claws 0.4× length of tarsus, with two rows of rounded denticles at basal half. Hind leg ( Fig. 17D–E ). Femur dorsal and ventral margin with one row of long spine-like setae; anterior surface with one row of spine-like setae near dorsal margin, one row of long spine-like setae near ventral margin; posterior surface with one row of spine-like setae near ventral margin at basal half. Tibia. Dorsally bare; ventral margin with one row of small spine-like setae; patella-tibial suture present. Tarsus. Ventral margin with one row of small spine-like setae. Tarsal claws 0.5× length of tarsus, with two rows of rounded and small denticles reaching apex.

ABDOMEN. Terga ( Fig. 18E ) with all segments white (color lost in alcohol), tergum IV with one medialred mark; tergum V with one large medial red mark; tergum IX with one red mark near lateral margin. Posterior margin of terga with small triangular blunt spines ( Fig. 18A ). Gills oblong, longer than next segment, with one medial trachea red pigmented. Paraproct ( Fig. 18B ) with two marginal spines, posterolateral extension with spines. Cerci ( Fig. 18C ) with lateral spines on every segment. Paracercus ( Fig. 18D ) without spines.

Figures

Fig. 16. Rivudiva naia sp. nov., holotype (UFRR). A. Labrum (left v.v., right d.v.). B. Left mandible. C. Right mandible. D. Maxilla. E. Hypopharynx. F. Labium (left v.v., right d.v.). G. Shape of distal rows of setae of glossa. Not to scale.

Fig. 17. Rivudiva naia sp. nov., holotype (UFRR). A. Foreleg (femur on anterior surface). B. Detail of fore claw. C. Posterior surface of forefemur. D. Posterior surface of hind femur. E. Hind leg (femur in anterior surface). Not to scale.

Fig. 18. Rivudiva naia sp. nov., holotype (UFRR). A. Margin of tergum IV. B. Paraproct. C. Cercus. D. Paracercus. E. Dorsal habitus of female nymph. Scale bar: E = 2.0 mm; A–D not to scale.