Metatarsonemus caissara Lofego & Cavalcante, 2019

Lofego, Antonio Carlos, Cavalcante, Ana Cristina Cerqueira, Demite, Peterson Rodrigo, Rezende, José Marcos, Ochoa, Ronald & Moraes, Gilberto José De, 2019, Reinstatement of Metatarsonemus Attiah (Acari: Tarsonemidae), with description of a new species, redefinition of the genus and a key to the world species, Zootaxa 4711 (2), pp. 307-329 : 314-319

publication ID	https://doi.org/ 10.11646/zootaxa.4711.2.5
publication LSID	lsid:zoobank.org:pub:0850D3FF-D053-49E0-B67C-A33DE117D1CB
DOI	https://doi.org/10.5281/zenodo.5685074
persistent identifier	https://treatment.plazi.org/id/039F87EE-FFAA-9250-71E8-FAB7FAB6DAA9
treatment provided by	Plazi
scientific name	Metatarsonemus caissara Lofego & Cavalcante
status	sp. nov.

Treatment

Metatarsonemus caissara Lofego & Cavalcante sp. nov.

( Figs 5–17 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURES 8–11 View FIGURE 12 View FIGURE 13 View FIGURES 14–17 )

Diagnosis. Adult of both sexes: Gnathosoma with a thick muscular pharyngeal pump, without a transverse groove on external ventral surface of gnathosomal capsule. Tibial I sensory cluster incomplete, missing ϕ1. Setae pl´´absent on tarsus II. Female: Vertical setae v1 slightly longer than scapular setae sc2; setae c1 slightly shorter than setae c2. Ventral surface of podosoma with fissures in two regions: a discrete pair of curved fissures on lateral region of coxisternal plate 1 and a small subcircular unpaired fissure at posterior end of poststernal apodeme. Male: vertical setae v1 longer than scapular setae sc2; setae c2 slightly longer than c1 and d. Apodeme 5 absent. Solenidion ω larger and more swollen on tarsus II than on tarsus I, approximately as long as basal width of tarsus II; leg IV with tibial tactile setae not longer than femorogenu.

Differential diagnosis: Adult females of this species differ from those of M. simplicissimus and M. megasolenidii by the absence of the pairs of coxisternal fissures near the base of 3b, and the tegula barely surpassing the posterior margin of trochanter IV, when the leg is directed behind. It further differs from M. simplicissimus by having sc2 slightly shorter than v 1 in females (state in M. simplicissimus ), and from M. megasolenidii by having ω of tarsus II shorter than tibia II in males. The male differs from other species of genus by the absence of a pair of apodemes 5.

Specimens examined. Holotype female and two paratype males: Ilha do Cardoso, Cananéia (25°04 S; 47°55 W), São Paulo State, Brazil, on Eugenia umbelliflora O.Berg. ( Myrtaceae) , 16 January 2013, deposited at Departamento de Zoologia e Botânica , Universidade Estadual Paulista (UNESP), São José do Rio Preto , São Paulo State, Brazil ; one paratype female: same locality, host and date as holotype, deposited at Departamento de Entomologia e Acarologia, Escola Superior de Agricultura “Luiz de Queiroz” (ESALQ), Universidade de São Paulo (USP), Piracicaba, São Paulo State, Brazil. All specimens collected by P.R. Demite. The specimens were found on leaves with associated fungi.

Description of female: two specimens measured (holotype given in boldface). Gnathosoma: subcircular in dorsal view and subtriangular in ventral view, length 31 –34, maximum width 32 –34; dorsal apodeme distinct. Setae dgs 15 and vgs 8 smooth; seta pp not observed. Palpus short, with two small subterminal setae and three terminal cone-shaped structures. Pharynx fusiform, 15– 17 long and 8 wide at widest region.

Idiosoma ( Figures 6 View FIGURE 6 and 7 View FIGURE 7 ): length 180– 185, width at level of c1 110– 112; prodorsal shield covering almost entire gnathosoma. Stigma on lateral margin of prodorsal shield, prominent, equidistant to bases of setae v1 and sc2. Lengths of setae: v1 19 –20, sc 1 12 –13, sc 2 16 –17 c1 11, c 2 13 –15, d 11, e 8– 9, f 11– 12, h 15. Setae slender, setae v1, c 1, c2, h, e; d and f serrate; sc2, smooth; sc1 capitate, with tiny spines. Distances between dorsal setae: v1–v1 29, sc2–sc2 56– 57, v1 –sc 2 24 –25, c1–c1 45, c2–c2 85, c1–c2 33– 37, d–d 37, f–f 19 –20, e–f 13– 15, h–h 25– 27.

Coxisternal setae 1a 6– 8, near middle of apodemes 1; 2a 10, near distal third of apodemes 2; 3a 13– 14, near medial end of apodemes 3; 3b 8 –9, near posterior end of apodemes 4. Setal alveolus 1b not discernible. Apodemes 1 conspicuous, extending diagonally near basal margin of trochanters I and II, not fused to anterior end of prosternal apodeme. Apodemes 2 short, not fused to prosternal apodeme. The latter conspicuous from region next to apodemes 1 to level of posterior end of apodemes 2, diffuse from this point to level of sejugal apodeme; conspicuous section with a median node; anterior half of diffuse section widened. Sejugal apodeme uninterrupted. Apodemes 3 extending diagonally from anterior end of trochanter III to about longitudinal level of insertion of 3a and with medial end foot-like. Apodemes 4 converging from insertion of 3b to central region of poststernal apodeme. Poststernal apodeme bifurcate anteriorly, diffuse in middle region and with a posterior node. Coxisternal plate I with a pair of curved fissures laterad of bases of 1a and 2a and an unpaired oval fissure at posterior end of poststernal apodeme. All coxisternal plates with tiny punctation marks. Tegula wide (16 –17) but short (5); posterior margin rounded. With a pair of ridges flanking tegula. Lateral extensions of coxisternal plate III-IV approaching behind, but not touching each other. All ventral setae smooth. Anterior margin of coxisternal plates III straight.

Legs ( Figures 8–11 View FIGURES 8–11 ): lengths (femur to tarsus – pretarsus not included): leg I 43 – 47, leg II 32 – 41, leg III 45 – 47, leg IV 33 – 34. Number of setae (solenidia in parentheses) on femur, genu, tibia and tarsus, respectively: leg I: 4-4- 6(1)+8(1), leg II: 3-3-4-5(1), leg III: 1+3-4-5. Tarsal solenidion ω of tibiotarsus I 4, stout, narrow near base. Sensory cluster of tibia I incomplete (missing φ1), solenidion φ2 2, robust, slightly capitate; famulus k 3, both inserted at approximately same level. Seta d of tibia I 30– 32, smooth. Femur I with proximal flange. Solenidion ω of tarsus II proximal, 4– 5 long, stout, narrow near base; seta pl´´absent. Seta d of tibia II 10- 13, serrate. Femorogenu IV 20 –23; tibiotarsus IV 9 –10. Length of leg IV setae: v´F 4, v´G 13, v´Ti 18 and tc´´29 –30; setae v´F, v´Ti and tc´´smooth; v´G serrate.

Description of male: two specimens measured. Gnathosoma: subcircular in dorsoventral view, length 30–32, maximum width 30; dorsal apodeme distinct. Setae dgs 10 and vgs 8, smooth, pp not observed. Palpus short, with two small subterminal setae and two terminal cone-shaped structures. Pharynx 10 long and 7 wide in widest region.

Idiosoma ( Figures 12 View FIGURE 12 and 13 View FIGURE 13 ): length 130–131, maximum width 105–110. Prodorsal shield with anterior margin rounded. Length of dorsal setae: v1 21, v 2 8–10, sc 1 11–12, sc 2 17–18, c 1 18–20, c 2 23–25, d 21–22, f 12–14. All setae setiform, thickened and serrate. Distances between dorsal setae: v1–v1 17, v2–v2 27, sc1–sc1 35, sc2–sc2 45, v1–v2 7–8, v2 –sc 2 17–19, sc1–sc2 6, c1–c1 73, c2–c2 86, d–d 43–44, c1–d 18–19, c1–c2 41, f–f 24–25. Seta sc2 laterad and slightly posteriad sc1; seta c1 closer to d than to c2, anterolaterad c2. Cupules not discernible.

Seta 1a 6–8, located near center of median half of coxisternal plate 1; seta 2a 10–11, located in center of coxisternal plate 2; seta 3a 13–15, near anterior end of apodeme 3; seta 3b 10, near middle level of apodeme 4. Setal alveolus 1b not discernible. All setae smooth. Apodemes 1 fused to anterior end of prosternal apodeme; apodemes 2 not fused to prosternal apodeme. Prosternal apodeme extending to sejugal apodeme, but interrupted medially near medial end of apodemes 2. Sejugal apodeme conspicuous and straight. Apodemes 3, 4, and poststernal apodeme conspicuous, connected to each other anteriorly by transversal lines, which together have a slightly a concave shape. All coxisternal plates punctate.

Legs ( Figures 14–17 View FIGURES 14–17 ): lengths (femur to tarsus – pretarsus not included): leg I 45 –47, leg II 42 –44, leg III 46 –47, leg IV 55 (claw not included). Number of setae (solenidia in parentheses) on femur, genu, tibia and tarsus, respectively: leg I: 4-4-6(1)-9(1), leg II: 3-3-4-5(1), leg III: 1+3-4-4. Solenidion ω of tarsus I 4, elongate. Setae ft’ placed near ω. Sensory cluster of tibia I composed only of solenidion φ2 2, very short, capitate, and famulus k 4, both inserted at approximately same level. Seta d of tibia I 25–26, smooth. Solenidion ω of tarsus II 6–7, proximal, robust, medially widest. Seta pl´´absent. Seta d of tibia II 15–17, serrate. Leg IV robust. Trochanter IV wider than long, 10–11 long and 24–25 wide; seta v’ 14–17, smooth. Femorogenu IV 35 –40 long and 23–25 wide at v´F level; posterior margin convex, anterior margin with a slight concavity at distal third. Setae v´F 4, v’G 15–16 and l”G 17–20, smooth. Tibia IV 9–10 long; solenidion φ 9, long, bacilliform; seta v’Ti 19–20, stout, serrate. Tarsus IV short, bearing 3 smooth setae, lengths: tc” 4, pv” 6 and u’ 7 –8. Claw well developed and unciform.

Etymology. The specific epithet ‘‘ caissara ’’ (from the Portuguese ‘‘caiçara’’, originally from the indigenous Tupi language), refers to people of traditional communities throughout the coast of São Paulo and Paraná states and also southern Rio de Janeiro state, the region where the type specimens of this new species were found.