Aphilodon angustatus Silvestri, 1909

(Fig. 18)

Aphilodon angustatus Silvestri 1909a: 269 (in key; original description); Silvestri 1909b: 56 (description), plate XI, figs 1–3; Chamberlin 1914: 209, 153; Attems 1929: 315 (in key), 316 (description); Bücherl 1940: 313 (description); Bücherl 1942b: 213 (new record), 216, 217; Bücherl 1942a: 365, 368, 369, 371; Pereira 1998: 473; Foddai et al. 2000: 105; Pereira et al. 2007: 41 (description, new record), 47 (in table), figs 41-62; Undheim et al. 2011: 515; Dugon & Arthur 2012: 129; Bonato et al. 2014: 487 (morphology), fig. 9a; Undheim et al. 2015: 681; Battirola et al. 2017: 5, 6 (new record), 8, 9, 10.

Type specimens. Syntypes: 1♀, 1♂, from “ Corrientes, S. Pedro ( Missiones [sic], Argentina)” (Silvestri, 1909b), F. Silvestri col., 1909; deposited in MCSG “ Vase type XVIII”; specimens labeled “a–b” .

Type locality. Argentina: Misiones: San Pedro: Corrientes .

Material examined. ARGENTINA. Misiones: Corrientes, San Pedro, 1909, F. Silvestri col., 1♀, 1♂ [syn- types] (MCSG). BRAZIL. Mato Grosso: Poconé, Pirizal (16°16’S, 56°22’W), 29/02/2004, J.L. Silva col., 1♀ (PD G 981) . São Paulo: Bananal (22°41’01” S, 44°19’24”W), 2010, J.M. Pereira col., 3♀, 1♂ (IBSP 3655); Caucaia do Alto, Reserva Morro Alto (23°41’S, 47°1’W), 07/2016, V.C. Calvanese col., 2♀, 1♂ (IBSP 4065); Iporanga, Parque Estadual do Alto do Ribeira (PETAR) (24°35’08”S, 48°35’35”W), 2010, J.M. Pereira col., 3♀, 2♂ (IBSP 3657) ; Paraná, Sangés (24°06’46”S, 49°27’49” W), 5♀ (IBSP 878) .

Diagnosis. A species of Aphilodon with: around 53–59 leg-bearing segments; known body length in adults 11–19 mm; cephalic plate length/width ratio 1.1–1.2; antenna ca. 2 times as long as cephalic plate; pectinate lamella of mandible with straight denticles; coxosternite of second maxillae not distinctly shorter in middle part; forcipular pretergite exposed; telopodite of second maxillae with article 3 shorter than article 2 and with 2 subapical setae and a short sensillum between; forcipule with lateral margin posteriorly straight; tarsungulum ca. 0.8–0.9 times as long as trochanteroprefemur+femur; forcipule with 3+1 denticles; distal denticle of trochanteroprefemur, denticle of femur and denticle of tibia relatively large and denticle of tarsungulum relatively small; distal denticle of trochanteroprefemur and denticle of femur separate; all pleurites conspicuous; each coxopleuron with 6–8 coxal pores in adults; ultimate presternite entire or apparently divided in middle part; metasternite of ultimate leg-bearing segment length/width ratio ca. 0.7; ultimate legs ca. 1.7–1.8 times as long as penultimate legs, with tarsus 1 1.1–1.2 times as long as tibia.

A. angustatus differs from all other species of Aphilodon by having: around 53–59 leg-bearing segments; body length less than 25 mm; distal denticle of trochanteroprefemur, denticle of femur and denticle of tibia relatively large and denticle of tarsungulum being relatively small (Fig. 18C); less than 10 coxal pores on each coxopleuron in adults.

Recorded specimens:> 25, including 17 ♀ and 5 ♂, from 10 localities.

Distribution. Argentina—Misiones: Corrientes, San Pedro (Silvestri 1909b). Brazil—Mato Grosso: Corumbá, Urucum (Silvestri 1909b); Poconé, Pirizal (Pereira et al. 2007); Nossa Senhora do Livramento (Battirola et al. 2017). Brazil—São Paulo: Bananal (new record); Cotia, Caucaia do Alto (new record); Iporanga, Parque Estadual do Alto do Ribeira (new record); “zona araraquarense” (Bücherl 1942a). Brazil—Paraná: Sangés (new record). Paraguay—Paraguarì (Silvestri 1909b).

Known variation. Sternite of the ultimate leg-bearing segment: shorter in middle in all specimens from Parque Estadual do Alto do Ribeira (PETAR) (N= 3♀, 2♂).