Anderemaeus mataderoensis, Norton & Ermilov, 2019

Norton, Roy A. & Ermilov, Sergey G., 2019, Anderemaeus (Acari, Oribatida) - overview, three new species from South America and reassessment of Anderemaeidae supported by ontogeny, Zootaxa 4647 (1), pp. 241-289 : 264-268

Anderemaeus mataderoensis sp. nov.

( Figs 17–19 )

Diagnosis

Anderemaeus species with large adults 763–830 × 498–547. Rostrum rounded, without mucro. Lamella without distinct cusp, lateral tooth or prolamella; pair moderately converging, such that mutual distance of setal pairs le and ro about equal. Transverse prelamellar ridge well developed, immediately anterior to seta le insertion. With three large tubercles anterior to sejugal groove, short seta in inserted at anterior base of each lateral tubercle. Bothridial seta long, baculiform, weakly barbed. Notogastral setae of medium size, barbed, most erect. Ventral keel of femora III, IV produced distally as large, triangular tooth; trochanters III and IV with short spine.

This is the only known Anderemaeus species with a conspicuously short interlamellar seta. Also, no other species is known to have the ventral keel of femora III, IV projected as a conspicuous, sharp tooth, though legs have not been described for most species. Only A. capitatus is as large, and it is easily distinguished by its capitate bothridial seta.

Adult

Measurements. Holotype (female) length 813, maximum notogastral width 531; range (paratypes) 763–830 × 498– 547. Without notable gender size difference.

Integument. Body color brown to dark brown. Lamellae, tutoria, pedotecta, lateral parts of prodorsum and epimere I foveolate. Cerotegument with excrescences of three types: amorphous, spherical and columnar (diameter and length of excrescences up to 10).

Prodorsum ( Figs 17A , 18A ). Rostrum rounded, without mucro. Lamella simple in form, without distinct cusp or prolamella; pair moderately converging, such that mutual distance of setal pairs le and ro about equal. Rostral bulge strongly developed, transverse prelamellar ridge present immediately anterior to end of lamellae and spanning their mutual distance. Laterorostral carina poorly developed, almost imperceptible in lateral view. With three transversely aligned large tubercles immediately anterior to sejugal groove, each lateral tubercle bearing seta in at its base. Setae ro (77–86), le (90–102) and ex (24–28) attenuate, weakly barbed. Seta in unusually small (36–41) baculiform, barbed. Bothridium with weak tubercle on posterior surface; bothridial setae (139–151) shorter than mutual distance of pair; baculiform, barbed, directed laterally.

Notogaster ( Figs 17A , 18 ). Without noticeable foveolation in reflected light. Humeral process strongly developed, crista moderately so. Notogastral setae of medium size, weakly barbed; c (73–82) attenuate, curved poste- riorly, others (la, lm, lp, 82–90; h 1 – h 3, p 1 – p 3, 53–61) erect, baculiform to acicular. Seta lm displaced anteriorly, far from level of la and closer to c; mutual distance of pair lm about twice setal length; h 2 aligned with h 1, h 3.

Coxisternum ( Figs 17B , 18A, C ). Enantiophysis e3 represented only by small posterior tubercle. Seta 3b borne by usually large tubercle, with lateral edge continuing posteriorly as low ridge directed across epimere III; seta 3c not on distinct tubercle. Aggenital enantiophysis (e4) unusually large ( Figs 17B , 18C ): anterior tubercle, bearing seta 4b, with medial edge extended anteriorly across epimere IV as low ridge; posterior tubercle elongated, reaching level posterior to seta ag. Epimeral setae attenuate, weakly barbed, 3c and 4c (53–61) longer than others (28–32).

Anogenital region ( Figs 17B , 18B ). Genital (28–32), aggenital (28–32), anal (20–24) and one pair of adanal (ad 3, 28–32) setae attenuate, weakly barbed; adanal setae ad 1, ad 2, (41–45) slightly thicker, more distinctly barbed. Preanal organ only slightly expanded internally.

Gnathosoma. Subcapitulum longer than wide (164–168 × 114–123). Subcapitular setae attenuate, slightly barbed, a (32–36) shorter than m and h (36–41). Adoral setae (16–20) attenuate, smooth. Palps (102–106) and postpalpal seta (6) spiniform, smooth. Chelicerae (164–168) typical of genus; seta cha (41–45) longer than chb (24–28).

Legs. Form and proportions of segments shown in Fig. 19 . Tarsi similar in length to respective tibia; all genua of similar size. Femora III slightly longer than wide (1.4:1), femur IV more elongated, about 1.8 x width; each with ventral keel produced distally as large, triangular tooth. Trochanters III and IV each with short, broad dorsodistally spine; IV also with small blunt proximal tooth. Form and locations of setae shown in Fig. 19 . Solenidion σ of genua I–III shorter than respective segment; φ of tibia IV little longer than segment width.

Juveniles (unknown).

Etymology

The specific name mataderoensis refers to the Matadero River, where the new species was collected.

Material examined

Holotype (female) and four paratypes (one female and three males): Chirimachay , Matadero River, drift net sample, 14-I-1977 (P. Turcotte). Since all other known Anderemaeus species are terrestrial, the occurrence of these specimens in moving water probably reflects an accidental displacement.

Type deposition

The holotype and one paratype are deposited in the CNC; three paratypes are deposited in the TSUMZ. All are preserved in ethanol with a drop of glycerol.

Figures

FIGURE 17. Anderemaeus mataderoensis sp. nov., adult (gnathosoma and legs omitted): A, dorsal view; B, ventral view. Scale bar 100 μm.

FIGURE 18. Anderemaeus mataderoensis sp. nov., adult, lateral view:A, anterior half; B, posterior third; C, mid-region. Scale bar 100 μm.

FIGURE 19. Anderemaeus mataderoensis sp. nov., adult legs (abaxial view): A, right leg I; B, trochanter to tibia of right leg II; C, trochanter to tibia of left leg III (tibia slightly twisted); D, right leg IV. Scale bar 50 μm.