Invreiella Suárez, 1966

Waldren, George C., Williams, Kevin A., Cambra, Roberto A. & Pitts, James P., 2020, Systematic revision of the North American velvet ant genus Invreiella Suárez (Hymenoptera: Mutillidae) with description of eleven new species, Zootaxa 4894 (2), pp. 151-205 : 156-158

Invreiella Suárez, 1966

( Maps 1, 2 )

Invreiella Suárez, 1966 [“1965”]: 472.

Type species (♀): Mutilla satrapa Gerstaecker, 1874 , by original designation. Brothers 1975: 590; Nonveiller 1990: 41; Lelej & Nemkov 1997: 19; Fernández 2001: 114; Lelej & Brothers 2008: 29; Pitts et al. 2010: 135; Quintero & Cambra 2011: 217; Brothers & Lelej 2017: 94; Pagliano et al. 2020: 102.

Diagnosis (female). Females are distinguished from other genera of Pseudomethocini by a combination of five characters. First, the procoxa is anteriorly dentate near the trochanter (fig. 63) ( Suárez 1966). Second, the pronotum has a carina of variable form separating the dorsal and lateral faces of the sclerite (here termed the pronotal carina, figs 30, 31, 35, 36, 41–43, 46–48, 53, 54, 96–109, 112–125) (Mickel, unpublished key to Neotropical Pseudomethoca (sensu lato) species; Suárez 1966). This carina is usually visible dorsally and laterally, but is sometimes obscure or absent in some species in lateral view (see the I. cephalargia species-group and I. suarezi species-group). The pronotal carina begins at the humeral angle at the dorsolateral margin of the mesosoma and continues posteriorly, curving ventrad usually just anterior to the pronotal spiracle. This carina can accentuate the distinctness of the pronotal sclerite from the mesopleural sclerite. Third, the gena is posteriorly carinate and ventrally produced into a process of variable form (here termed the genal process, figs 28, 29, 32–34, 51, 52, 65–78) (Mickel, unpub. key; Suárez 1966). Fourth, the first metasomal segment is sessile with the second segment and is not petiolate (figs 9–22); further, T1 is short and transverse in dorsal view, with anterior and dorsal surfaces (not separated by a transverse carina), the anterior surface flattened. Finally, a pygidial plate is present and laterally defined by a carina, the sculpture of the plate being transversely rugose to rugose-granulate. Male. Unknown.

Description (female). Body length 7.49–12.95 mm.

Setae: Setae simple, without brachyplumose or plumose setae.

Head: Head 0.93–1.35 × as wide as mesosoma, quadrate in dorsal view. Sides of head diverging dorsally to ventrally in frontal view, with base of mandible extending beyond exterior-most protrusion of eye. Occipital carina present yet incomplete, dorsally distinct and ventrally obscure, not reaching or connected to hypostomal tooth. Weak median longitudinal impression spanning from vertex to frons present. Eye circular, protruding. Distance from posterior margin of eye to posterolateral corner of head 0.93–2.13 × maximum diameter of eye. Malar space short, with eye close to base of mandible. Antennal scrobe carinate dorsally, prominent, arcuate to straight in form, not spinose or conspicuously tuberculate at inner point of termination dorsad antennal rim, not overlapping antennal rim though sometimes close to touching it. Antennal rims well-separated, not connected basally. Scape arcuate, long, with single ventral carina and moderate scattered punctures. Antenna with 10 flagellomeres, cylindrical in cross section. F1 1.56–2.89 × as long as F2. Clypeus either flattened, rugose-granulate, and bituberculate medioapically, or with complete/medially interrupted transverse arcuate carina and lateral tubercle ventrad to carina. Mandible dorsally and ventrally carinate, with row of punctures anterior to and closely parallel to each carina, punctures each bearing long raised seta, forming row. Mandible apically tridentate, inner second tooth small, parallel with base of mandible, inner third tooth large and triangular, directed dorsally. Mandible with internal angulation midway between third apical tooth and dorsal base of mandible. Base of mandible without ventral tooth. Genal process present, either denticulate, triangular, or spinose in form, with posterior genal carina present, either convex, straight, or sinuate in form. Genal carina sometimes continuing beyond apex of process anteriorly, becoming obscure between proboscidal fossa and genal process, faintly appearing to curve across genal venter and terminate into weak to moderate hypostomal tooth. Postgenal bridge present, transversely rugose-striate, with midventral line. Proboscidal fossa triangular, separated from pleurostomal fossa by cuticular bridge. Maxillary palp with 6 palpomeres, labial palp with 4 palpomeres. Third labial palpomere transversely expanded.

Mesosoma: Mesosoma 0.99–1.42 × as wide as long, widest at pronotal carina or pronotal spiracle. Anterodorsolateral margin of pronotum usually outcurved. Humeral angle prominently carinate, terminating into tuberculate epaulet at anterodorsolateral margin of pronotum. Pronotal carina often present, separating dorsal and lateral faces of pronotum, or sometimes absent, with cluster of dense, contiguous, crenulate punctures in its place, simulating weak carina. Pronotal-mesonotal suture obscure. Metanotal-propodeal suture obscure to absent. Scutellar area with scutellar scale absent. Mesosoma constricted at propodeal spiracle in dorsal view, with dorsolateral margin of propodeum expanded and usually wider than point of constriction at propodeal spiracle in dorsal view. Posterior face of propodeum weakly concave. Dorsolateral margin of propodeum serially lined with blunt denticles, denticles sometimes conjoined. Mesopleuron without vertical carina, with variable vertical column of moderate punctures anterior to mesopleural-metapleural suture, punctures sequential at dorsal half of sclerite and becoming more separated at ventral half, punctures and suture close in proximity roughly at midpoint and diverging at dorsal and ventral sections, punctures sometimes anteriorly and/or posteriorly tuberculate. Mesopleuron posteriorly carinate at least along ventral half of mesopleural-metapleural suture, carina terminating roughly at midpoint of suture or beyond it, sometimes diverging from suture and continuing to dorsolateral margin of mesosoma. Dorsal portion of mesopleural-metapleural suture absent, obscure, or present, terminating into tubercle anterior to propodeal spiracle at dorsolateral margin. Propleural cavity at coxal insertion anteriorly bound by prominent, arcuate carina. Metasternal process present between metacoxae.

Legs: Procoxa anteriorly dentate near trochanter. Internal margin of metacoxa with longitudinal carina. Protarsal rake present. Meso- and metatibiae dorsally with two longitudinal rows of stout cylindrical spines, with internal row more prominent. Tibial spur formula 1-2-2. Tarsal claws with three stout setae on internal margin of each hook.

Metasoma: First metasomal segment sessile with second segment. T1 short, transverse in dorsal view, with anterior and dorsal surfaces, without transverse carina separating surfaces, anterior surface flattened. T2 evenly convex, without longitudinal carinae or lateral protrusions, merely punctate. Felt line present on T2, absent on S2. S1 with longitudinal carina, without distinctive tubercles present on carina. S2 with weak to moderate transverse basal carina in shape of wide “V.” Pygidium with pygidial plate present, laterally defined by carina, with sculpture of plate transversely rugose to rugose-granulate.

MALE. Unknown. An attempt was made to associate some male-based species of Pseudomethoca (sensu lato) with Invreiella females using distribution and similarity in size. The few promising candidates for Invreiella males were also potential males for several Pseudomethoca species, such as Pseudomethoca bethae Krombein, 1992 in the southwestern USA.

Etymology: Named after the Italian hymenopterist Dr. Fabio Invrea (1884–1968).

Distribution: Mexico (Chiapas, Chihuahua, Coahuila, Durango, Guanajuato, Guerrero, Hidalgo, Jalisco, Mexico, Michoacan, Morelos, Nayarit, Oaxaca, Puebla, San Luis Potosi, Sinaloa, Sonora, Veracruz, and Zacatecas); USA (Arizona and New Mexico).

Biogeography: Mexican transition zone; Nearctic region; Neotropical region.

Host(s): Unknown.

Remarks: At the time of his description of Invreiella, Suárez (1966) only knew of two species, I. cardinalis and I. satrapa . It seems that Suárez examined only one specimen of each species, which are housed at MNCN. With the description of eleven new female-based species and the addition of I. cephalargia , comb. nov., generic redescription of the females became necessary to account for this increase in known diversity. Variation in the pronotal carina is especially notable: in two species-groups it is reduced or essentially absent ( I. cephalargia and I. suarezi speciesgroups, respectively), in contrast to the I. satrapa species-group, where the pronotal carina is the most prominently developed in the genus. The shape of the dorsolateral margin of the mesosoma in dorsal view (figs 96–109), when coupled with the form of the pronotal carina, is valuable for delimiting species-groups and species.

Determining relationships between Invreiella and members of Pseudomethoca (sensu lato) is outside the scope of this study; the present catch-all nature of Pseudomethoca requires a comprehensive analysis of its constituent taxa. Invreiella is not present in either of the published keys to the New World mutillid genera ( Manley & Pitts 2002; Brothers 2006a). We have provided several couplets at the beginning of the key to Invreiella females to help the user distinguish this genus from other members of Pseudomethocini .

Figures

MAP 1. Geographic distribution of Invreiella species. MAP 2. Biogeographic distribution of Invreiella species (shapefiles from Morrone et al. 2017).