Rivudiva amazona, 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 : 162-164

Rivudiva amazona sp. nov.

urn:lsid:zoobank.org:act:595B6165-BC4E-4AFB-BF4F-CD6FB5C22432

Figs 4–7

Rivudiva trichobasis – Falcão et al. 2011: 539.

Diagnosis

NYMPH. The combination of the characters: 1) labrum with distal margin straight ( Fig. 4A ); 2) labrum ventral surface with robust, distally bifid, eventually pectinated, setae on distal margin ( Fig. 4A ); 3) left mandible with incisors fused at basal third ( Fig. 4B ); 4) maxillary palp segment II with reduced apical lobe ( Fig. 4D ); 5) hypopharynx without distomedial projection ( Fig. 4F ); 6) glossa oval with inner and outer arcs of setae not sinuous and close to margins ( Fig. 4G–H ); 7) labial palp segment III robust, conical and apically pointed ( Fig. 4G ); 8) dorsal margin of forefemur with one row of long setae from middle length to apex ( Fig. 5A ); 9) forefemur on anterior surface with long blunt setae at middle ( Fig. 5A ); 10) patella-tibial suture present; 11) distal margin of terga with elongated triangular spines ( Fig. 6A ).

Etymology

The name ʻ Amazonas ʼ was given to native South American women after they attacked a conquest expedition. This species is named in honor of these brave native women. Name in apposition.

Material examined

Holotype BRAZIL • nymph on slide; Roraima, Caroebe, River Caroebe , vicinal 05 ; 00°54′47.3″ N, 59°34′19.9″ W; 19 Mar. 2013; P.V. Cruz, N. Hamada, R. Boldrini and G. Petronilo leg.; sand; INPA.

Paratypes BRAZIL • 14 nymphs; same collection data as for holotype; INPA • 2 nymphs on slide; same locality as for holotype; 12 Mar. 2018; P.V. Cruz and I.O. Fernandes leg.; sand; INPA .

Additional material

BRAZIL • 4 nymphs; Roraima, BR-170, 41 Km turn to BR-432, old bridge, right from Vila de Santa Rita; 02°08′59.9″ N, 60°40′39.9″ W; 28 Mar. 2012; P.V. Cruz, N. Hamada, R. Boldrini and G. Petronilo leg.; sand; INPA • 3 nymphs; Roraima, Pacaraima, River Ereu ; 04°02′02.9″ N, 61°23′09.5″ W; 26 Mar. 2012; P.V. Cruz, N. Hamada, R. Boldrini and G. Petronilo leg.; INPA • 3 nymphs; Roraima, São João da Baliza, Ramal 27 , stream Lajinha ; 01°00′59.7″ N, 59°55′53.1″ W; 24 Mar. 2012; P.V. Cruz, N. Hamada, R. Boldrini and G. Petronilo leg.; INPA • 1 nymph; Roraima, Caroebe, Ramal 37 , River Caroebe , Cachoeirinha farm ; 00°57′09.2″ N, 59°37′00.5″ W; 23 Mar. 2012; P.V. Cruz, N. Hamada, R. Boldrini and G. Petronilo leg.; INPA .

Description

Nymph

LENGTH. Body, 3.3–3.5 mm.

HEAD. Antenna. Scape and pedicel with spine-like setae; flagellum with minute spines on apex of each segment. Labrum ( Fig. 4A ). Rectangular, length about 0.6× maximum width; distal margin straight, one row of robust, distally bifid, 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 one row of thin setae, and many thin setae over surface (not illustrated). Left mandible ( Fig. 4B ). Incisors partially cleft in two sets (fused at basal third); outer and inner sets of incisors respectively with 4 + 3 denticles, outer incisor with spine-like process; prostheca robust and pectinated; margin between prostheca and mola straight; tuft of spine-like setae at base of mola present; subtriangular process wide; denticles of mola constricted; mola with one large denticle; outer margin convex. Right mandible ( Fig. 4C ). Incisors fused at base; outer and inner sets of incisors respectively with 3 + 3 denticles, outer incisor with spinelike process; prostheca stout, bifurcated at apex, inner lobe longer; margin between prostheca and mola almost straight; tuft of spine-like setae at base of mola present; denticles of mola not constricted; apex of mola with one simple setae; first process of mola rounded, second expanded and straight; outer margin convex. Maxilla ( Fig. 4D–E ). Maxillary palp 1.7× length of galea-lacinia; segment II 1.1× length of segment I; segment II inner margin straight, outer margin on apex straight, reduced apical lobe; ventral canine enlarged, not laterally expanded; set of distal setae of inner-ventral row rounded. Hypopharynx ( Fig. 4F ). Lingua longer than superlingua, sub-quadrangular without distomedial projection covered by tuft of simple setae; superlingua with rounded outer margin; short, thin, simple setae scattered over distal margin of lingua and superlingua. Labium ( Fig. 4G–H ). Glossa oval, slightly broad at base, distally rounded, shorter than paraglossa; inner margin without row of setae; ventral surface covered by thin setae; dorsal surface with inner arc close to inner margin, and outer arc not sinuous and close to outer margin; one small robust blunt seta on apex. Paraglossa curved inward; apex with one row of robust and long spine-like setae; outer margin without setae; dorsal surface with two longitudinal rows of setae, one near to inner margin, one near to outer margin, distally with long robust setae; 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, with almost straight distal margin, covered with thin setae; segment III robust, conical, and apically 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 setae.

THORAX. Foreleg ( Fig. 5A–C ). Femur length about 2.6× maximum width; dorsal row of setae from distal half to apex; anterior surface with one medial row of long blunt setae, one row of short blunt setae near dorsal margin; posterior surface with one row of long spine-like setae near ventral margin from base to 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 conical denticles not reaching apex. Hind leg ( Fig. 5D–E ). Femur anterior surface with one row of spine-like setae near dorsal margin reaching apex, one row of long spine-like setae near ventral margin reaching apex, one row of spine-like setae near middle; posterior surface with one row of spine-like setae near ventral margin from base to apical third. Tibia. Dorsally bare; ventral margin with one row of small blunt setae, patella-tibial suture present. Tarsus. Ventral margin with one row of small blunt setae. Tarsal claws 0.4× length of tarsus, with two rows of small conical denticles not reaching apex.

ABDOMEN. Terga ( Fig. 7 ) with all segments white (color lost in alcohol), terga I–IX with two small medial dots, sometimes dots absent; tergum I with one large dot on disto-lateral margin (rare); eventually tergum II, III and IX darker or with large brown pigmentation; terga III and VI with one large medial mark near distal margin; terga VI and VII with disto-lateral transversal brown mark (rare). Posterior margin of terga with elongated triangular spines ( Fig. 6A ). Gills oblong, longer than next segment, with one medial trachea pigmented. Paraproct ( Fig. 6B ) with nine to eleven marginal spines, posterolateral extension with spines (broken in holotype and illustrated). Cerci ( Fig. 6C ) with lateral spines on every segment. Paracercus ( Fig. 6D ) without spines.

Comments

The differences in deepness of the curvature of the distal lobe on the maxillary palp segment II is related to the slide artifact ( Fig. 4E ).

Figures

Fig. 4. Rivudiva amazona sp. nov., holotype (INPA). A. Labrum (left v.v., right d.v.). B. Left mandible. C. Right mandible.D. Left maxilla.E. Variation of maxillar palp segment II (right maxilla).F. Hypopharynx. G. Labium (left v.v., right d.v.). H. Shape of distal rows of setae of glossa. Not to scale.

Fig. 5. Rivudiva amazona sp. nov., holotype (INPA). A. Foreleg (femur on anterior surface). B. Detail of fore claw. C. Posterior surface of forefemur. D. Hind leg (femur on anterior surface). E. Posterior surface of hind femur. Not to scale.

Fig. 6. Rivudiva amazona sp. nov., holotype (INPA). A. Margin of tergum IV. B. Paraproct. C. Cercus. D. Paracercus. Not to scale.

Fig. 7. Rivudiva amazona sp. nov., dorsal habitus of nymphs, variation of pigmentation pattern. A. Holotype (INPA). B–J. Paratypes (INPA). Scale bar = 1.65 mm.