Mastigoproctus vandevenderi, Barrales-Alcala, Francke & Prendini, 2018

Barrales-Alcalá, Diego, 2018, Systematic Revision Of The Giant Vinegaroons Of The Mastigoproctus Giganteus Complex (Thelyphonida: Thelyphonidae) Of North America, Bulletin of the American Museum of Natural History 2018 (418), pp. 1-64 : 46-47

Mastigoproctus vandevenderi , sp. nov.

TYPE MATERIAL: MEXICO: Sonora: Municipio Yecora: holotype ♂ ( CNAN T1146 ), paratype ♂, paratype ♀ ( CNAN T1147 ), paratype ♂, paratype ♀ ( AMNH), paratype ♂ ( CAS), Yecora, Puerto La Cruz road to Mesa del Campanero , 28°21′58.788″N 109°01′48.709″W, 2009 m, 19. viii.2016, D. Barrales and T. Lasso, mixed pine/ oak forest ; paratype ♂ ( CNAN T1148 ), Yecora, Cabañas El Campanero , 28°22′14.53″N 109°01′42.28″W, 2018 m, 30.x.2014, G. Contreras and J. Mendoza, under rock ; 2 ♂ paratypes ( CAS), [Moctezuma], near 28.55°N 109.45°W, 18.ix.1982, V. Roth, pine forest .

ETYMOLOGY: This species is dedicated to Thomas van Devender, an ecologist and naturalist who has worked for many years on the flora and fauna of the state of Sonora and the southern part of the United States. Van Devender’s contributions have helped biologists obtain a better understanding of the biota of northern Mexico.

DIAGNOSIS: Mastigoproctus vandevenderi , sp. nov., resembles M. mexicanus , from which it differs as follows. Adult M. vandevenderi are sparsely setose and brownish in color whereas adult M. mexicanus are densely setose and reddish. Spines S3 and S4 on the prodorsal margin of the pedipalp trochanter of the adult male are equal in M. vandevenderi whereas spine S3 is longer than the other spines in M. mexicanus . The tubercles on the retrolateral surface of the pedipalp femur are curved and cup shaped in M. vandevenderi but straight and digitiform in M. mexicanus . The seminal receptacles of the spermathecae are narrow, triangular, and posteriorly directed in M. vandevenderi but swollen, obovate and anteriorly directed in M. mexicanus .

DESCRIPTION: The following description is based on seven males and two females.

Total length: Maximum length from anterior margin of carapace to posterior margin of opisthosomal segment XII (pygidium) in adult specimens 59.7 mm (♂) and 45.1 mm (♀) (table 5).

Color: Carapace, dark reddish brown. Tergites I–IX dark reddish brown. Sternites I–III reddish brown, lateral margins dark reddish brown; IV– IX dark reddish brown, lateral margins dark brown. Pygidium, dorsal and ventral surfaces dark reddish brown. Flagellum reddish brown, segments with reddish macrosetae. Pedipalp trochanter, dorsal and ventral surfaces dark reddish brown, prolateral surface with reddish macrosetae; femur, patella, tibia, and basitarsus, dorsal and ventral surfaces dark reddish brown, mesal surfaces with reddish macrosetae. Leg I, coxa, trochanter and basitarsus reddish brown; femur, patella, and tibia dark reddish brown; II–IV coxae, ventral surfaces light reddish brown; trochanter, femora, patellae, and tibiae, dorsal surfaces reddish brown, ventral surfaces dark reddish brown; basitarsi and tarsi reddish brown.

Carapace: Epistoma visible in dorsal aspect. Pair of strongly developed carinae anterolaterally, extending from lateral ocelli to two-thirds the distance to median ocular tubercle (fig. 10D). Three pairs of lateral ocelli with accessory translucent eyespot situated between anterior and posterior ocelli; anterior ocelli larger than median and posterior ocelli; anterior two pairs slightly separated from posterior pair by tubercle, distance between median and posterior ocelli 4× distance between anterior and median ocelli. Median ocular tubercle smooth, situated in anterior 10% of carapace (table 5); distance between ocelli 1.5× ocular diameter. Carapace anterior and medial surfaces rugose, mediolateral and posterior surfaces densely granular. Posterior fovea present, distinct.

Chelicerae: Retrolateral surface with stridulatory surface (plectrum), comprising approximately 13 short, stout (ca. 5× longer than wide), anteroventrally directed spiniform macrosetae (figs. 4H, 5H); mesal surface with few short, stout, anteroventrally directed spiniform macrosetae.

Pedipalps: Cuticle tuberculate and punctate. Coxa, retrolateral and ventral surfaces rugose; coxal apophysis with one terminal spine; prodorsal surface with long, retroventrally directed macrosetae inserted in cristulae, forming stridulatory surface (pars stridens) (fig. 6H). Trochanter longer than wide (♂) or subequal (♀); retrodorsal surface with cristulae (♂) or punctate (♀), and setose; prodorsal margin with five terminal spines (S1–S5) and one subterminal accessory spine ( AS), all sharply pointed, except for AS which is blunt (fig. 8E), varying in size such that S3 ≥ S4> S5> S2> S1> AS (♂; fig. 8E) or S4> S5 ≥ S3> S2> AS ≥ S1 (♀; fig. 8F); space between S3 and S4 equal to or longer than length of longest spine (♂) or equal to space between S4 and S5 (♀); prolateral surface with several spiniform tubercles and reddish macrosetae (♂); proventral margin with two spines (♂). Femur laterally compressed (♂) or terete (♀), almost 2× (♀) to 2.5× (♂) longer than wide (table 5); prolateral surface with two spines, one prodorsal, short, blunt (♂) or sharply pointed (♀), the other proventral, blunt, rounded, length one-eighth femur width (♂; fig. 9H) or short, sharply pointed, and situated apically (♀); retrolateral surface with digitiform tubercles (longer in ♂). Patella slightly shorter (♂) or longer (♀) than tibia (table 5); prolateral surface with reddish macrosetae, one vestigial (♂) or distinct, sharp (♀) spine situated distally on proventral margin; one vestigial (♂) or distinct, sharp (♀) spine at base of patellar apophysis; retrolateral surface tuberculate (tubercles larger and more numerous in ♂). Patellar apophysis elongated, almost one-quarter carapace length, smooth and slender (♂) or shorter and robust (♀); prolateral margin with row of blunt (♂) or sharply pointed (♀) denticles; retrolateral margin smooth (♂) or with few denticles (♀), with subterminal macrosetae. Tibia longer than wide, laterally compressed (♂) or terete (♀); prodorsal surface with row of denticles; prolateral surface with several reddish macrosetae; proventral margin with two spines distally; retrolateral surface with few shorter macrosetae; fixed finger, dorsal and ventral margins each with row of denticles. Basitarsus (movable finger), dorsal and ventral margins each with ser- rate row of denticles; prolateral surface with several reddish macrosetae; apex bifid (♂).

Legs: Leg I, basitarsal and telotarsal tarsomeres I–VII gradually decreasing in length, with tarsomere I longest, tarsomere VIII four-fifths length of tarsomere I. Legs I–III coxae, lateral surfaces and IV, dorsal and lateral surfaces each with setose spiniform tubercles. Legs I–IV trochanters, dorsal and lateral surfaces with setose spiniform tubercles; femora dorsal and ventral surfaces with setose spiniform tubercles, situated proximally on I, II, prolateral surface with setose spiniform tubercles, III and IV retrolateral surface smooth, prolateral and retrolateral surfaces smooth; II–IV retroventral surfaces each with setose spiniform tubercle terminally, with macroseta inserted terminally; tibiae each with one ventrodistal spur; basitarsi each with two ventrodistal spurs. Leg I tibia with two trichobothria distally; legs II–IV tibiae each with one trichobothrium distally.

Opisthosoma: Tergites finely granular; I divided by weak median longitudinal suture restricted to anterior and posterior margins; II with median longitudinal suture extending from midsegment to posterior margin; III with median longitudinal suture extending from anterior margin to one-third length of segment; X (first segment of pygidium) with distinct lateral longitudinal sutures (pleuron); XII with pair of oval ommatoids posterolaterally. Sternite II (genital) with pair of cup shaped (♂) or lanceolate (♀) depressions submedially, posterolateral surfaces inflated (♂) or flat (♀), and posteromedian margin protruding markedly (♂) or slightly (♀) posteriorly into median lobe that overlaps sclerotized area in space between sternites II and III (♀) ; III divided longitudinally (♂) or undivided (♀), linear (♂) or with pronounced emargination (♀) anteriorly, posterior margin with (♂) or without (♀) median bulge with patch of reddish macrosetae (♂) ; IV with (♂) or without (♀) median longitudinal suture extending from anterior margin to one-third length of segment ; V with (♂) or without (♀) patch of fine macrosetae medially ; VI–IX surfaces smooth, asetose.