Taxonomic revision of the Trapdoor spider genus Eucteniza Ausserer (Araneae, Mygalomorphae, Euctenizidae)

Abstract The mygalomorph spider genus Eucteniza Ausserer, 1875 comprises 15 nominal species known only from the southwestern United States (Texas) and Mexico (Northern, Central, and the Baja Peninsula). Eucteniza atoyacensis Bond & Opell, 2002 is considered a nomen dubium; E. rex (Chamberlin, 1940) and E. stolida (Gertsch & Mulaik, 1940) are both considered junior synonyms of E. relata (O.P.-Cambridge, 1895). Twelve new species are described: E. caprica, E. coylei, E. diablo, E. cabowabo, E. huasteca, E. zapatista, E. chichimeca, E. ronnewtoni, E. hidalgo, E. golondrina, E. panchovillai and E. rosalia.


Introduction
The trapdoor spider Eucteniza Ausserer, 1875 (subfamily Euctenizinae) is the most distinguishable of the genera currently placed in the recently recognized North American spider family Euctenizidae (see Bond et al. 2012). Known species have a unique mating clasper (modifications of the first walking leg) that comprises a mid-ventral tibial megaspine with similar modifications to the second walking leg. Members of the genus also have a lightly sclerotized, "soft", dorsal posterior aspect of the carapace that is very noticeable in live and preserved specimens. The distribution of the genus is largely restricted to the US state of Texas and northern/central Mexico (Fig. 1). As such, the habitat is predominantly low elevation, desert and tropical dry forest. The relatively few female specimens that have been hand collected were recovered from silk-lined burrows, reminiscent of Ummidia Thorell, 1875 (see Bond and Coyle 1995) -they have a thick silk lining and heavy "cork"-like trapdoor.
Phylogenetic placement of the genus has been historically problematic. Until recently, Eucteniza was the type genus for the cyrtaucheniid subfamily Euctenizinae (see Raven 1985, Bond and. Morphological cladistic analyses (Bond and Opell 2002) and subsequent molecular phylogenetic analyses  clearly demonstrated Cyrtaucheniidae to be polyphyletic; imprecisely referenced as "possibly paraphyletic" by Platnick (2013) in the World Spider Catalog citing an older now superseded study by Goloboff (1993). The most recent multi-gene molecular phylogenetic analysis of the mygalomorph families by Bond et al. (2012) clearly supported a monophyletic Euctenizinae, which was sister to idiopids, and a polyphyletic Cyrtaucheniidae. Consequently the subfamily was elevated to family status and currently comprises seven genera: Apomastus Bond & Opell, 2002, Aptostichus Simon, 1891, Entychides Simon, 1888, Eucteniza Ausserer, 1875, Myrmekiaphila Atkinson, 1886, Neoapachella Bond & Opell, 2002, and Promyrmekiaphila Schenkel, 1950. Upon relimitation of the subfamily Euctenizinae by Bond et al. (2012), Eucteniza is considered more closely related to Promyrmekiaphila, Neoapachella, Entychides, and a potentially new genus from California. Although some analyses render Entychides paraphyletic with respect to Eucteniza, members of these two genera are very distinct morphologically and thus Entychides paraphyly is likely an artifact of limited sampling.
Like other euctenizid genera, the taxonomic history of Eucteniza is brief but does include a number of generic level synonyms. First described by Ausserer (1875), subsequent species were proposed but were all placed into other genera later considered by Bond and Opell (2002) to be junior synonyms. The North American species, E. rex (Chamberlin, 1940) and E. stolida (Gertsch & Mulaik, 1940) were originally described as Astrosoga Chamberlin, 1940 taxa, a genus proposed by Chamberlin (1940) as closely allied with Myrmekiaphila. Flavila O.P. -Cambridge, 1895 and Enrico O.P. -Cambridge, 1895 were earlier names proposed for Mexican species; Flavila was shortly thereafter recognized as a junior synonym of Eucteniza by F.O.P.- Cambridge (1897) with the synonymy of Enrico following much later (Bond and Opell 2002).
We present here the first species level taxonomic revision of the genus Eucteniza; this is the tenth paper in a series of taxonomic revisions and reviews and phylogenetic treatments undertaken by the first author (JEB) seeking to resolve the taxonomy of the North American euctenizid genera and species (Bond and Opell 2002, Bond 2004, Bond and Platnick 2007, Bailey et al. 2010, Bond 2012. Unfortunately, Eucteniza specimens are rare in collections and difficult to collect (Bond pers. obs.) thus with the exception of Eucteniza relata (distributed widely throughout Texas and Northern Mexico), most of the species described herein are based on relatively little material and most are known only from male specimens. Moreover, a number of species, to include the type species for the genus, were originally described from juvenile specimens; one such species, E. atoyacensis Bond & Opell, 2002 is considered herein a nomen dubium. Given the paucity of material it is our hope that this work will catalyze interest in the genus and facilitate future studies.
Species concept applied: Species were delineated using a traditional morphological species concept wherein species are defined as those populations (or groups of populations) that represent qualitative differences in phenotype that differ in a discrete manner from other populations or groups.

Materials and methods, abbreviations
The following institutional and quantitative morphological abbreviations used in this paper are defined as follows: Institutional AMNH (American Museum of Natural History; New York, New York), AUMNH (Auburn University Museum of Natural History; Auburn, Alabama), BMNH (British Museum of Natural History; London), CAS (California Academy of Sciences; San Francisco, California).

Quantitative Morphological
These features are explicitly defined and illustrated in Bond (2012).

ANTd
number of teeth on the anterior margin of the female cheliceral fang furrow Cl, Cw carapace length and width. Carapace length taken along the midline dorsal most posterior position to the anterior front edge of the carapace (chelicerae are not included in length). Carapace width taken at the widest point LBl, LBw labium length and width taken from the longest and widest points, respectively PTl, PTw male palpal tibia length and width Bl palpal bulb length from embolus tip to the bulb base, taken in the ventral plane at its longest point PTLs, TBs number of female prolateral patella and tibial spines leg III STRl, STRw sternum length and width. Sternum length from the base of the labium to its most posterior point. Width taken across the widest point, usually between legs II and III TSrd, TSp, TSr number of tibia I spines on the distal most retrolateral, prolateral, and midline retrolateral positions

Measurement, characterization, and illustration of morphological features
Unique voucher numbers were assigned to all specimens (alphanumeric designations beginning with EU, MY, or UMM); these data were added to each vial and can be used to cross-reference all images, measurements, and locality data. All measurements are given in millimeters and were made with a Leica M165c dissecting microscope equipped with the Leica Analysis Suite Software. Lengths of leg articles were taken from the mid -proximal point of articulation to the mid -distal point of the article (sensu Bond 2012, figures 11-16). Leg I and Leg IV article measurements are listed in the species descriptions in the following order: femur, patella, tibia, metatarsus, tarsus. Carapace and leg coloration are described semi-quantitatively using Munsell® Color Charts (Windsor, NY) and are given using the color name and color notation (hue value/chroma). Mating clasper line drawings were first recorded as digital images and then traced as vector drawing objects using Adobe Illustrator (Adobe Systems Inc.). Digital images of specimens were made using a Visionary Digital Imaging System (Visionary Digital TM , Richmond, VA) where images were recorded at multiple focal planes and then assembled into a single focused image using the computer program Helicon Focus (Helicon Soft, Ltd., Ukraine). The female genital region was removed from the abdominal wall and tissues dissolved using trypsin; spermathecae were examined and photographed in the manner described above. Following Bond (2012) and Bond and Taylor (2013) habitus illustrations were constructed from whole body images that were bisected, copied, and reflected in Adobe Photoshop (Adobe Systems, Inc.) to produce a roughly symmetrical image; the actual raw image on which the habitus illustration is based has been deposited in Morphbank and its record number noted in the figure legend (value in square [ ] brackets). Unless otherwise stated, scale bars = 1.0 mm.

Locality data and georeferencing
Latitude and longitude for all collecting localities were recorded in the field using a Garmin® Global Positioning System receiver (Garmin International Ltd., Olathe, KS) using WGS84 map datum. For previously collected specimens (e.g., loaned museum specimens) locality data were georeferenced by hand by finding the approximate locality using Google Earth (WGS84 datum). A distribution map was constructed using ArcGIS using NAD83 map datum. Specimens without latitude and longitude data were georeferenced as described by Bond (2012). Precision for each georeferenced point is annotated as a superscript in each material examined section of the species' taxonomy using the confidence value scheme employed by Murphey et al. (2004): 1 = exact coordinates given; 2 = amended exact coordinates (i.e., exact coordinates given but were emended on validation); 3 = public land survey system; 4 = within 1km radius; 5 = within 5km radius; 6 = within 10km radius; 7 = to county or > 10km; 8 = to state; 9 = to project region. Latitude and longitude are recorded to the 4 th decimal place as an indication of the precision in the point assigned by us (i.e., where we have assigned the locality place-holder for the specimen in question), not precision in the recording of the value or to specify the exact point of collection. Detailed locality and associated GIS data as supplemental data files in spreadsheet and KML file format can be downloaded online from the Dryad Data Repository at doi: 10.5061/dryad.6dc14.

Data resources
The data underpinning the analysis reported in this paper (see below) were deposited on 18 November 2013 in the Dryad Data Repository at doi: 10.5061/dryad.6dc14 and at GBIF, the Global Biodiversity Information Facility, http://ipt.pensoft.net/ipt/ resource.do?r=eucteniza_data. Images associated with species descriptions have been deposited in Morphbank (http://www.morphbank.net); Morphbank image record numbers are noted in brackets by each figure in the figure legend.

Taxonomy
Family Euctenizidae Raven, 1985 Type genus. Eucteniza Ausserer, 1875 Subfamily Euctenizinae Raven, 1985 http://zoobank.org/C27FB688-5D8E-4E77-ABCC-FD108DC4C22D Included genera. Entychides Simon, 1888;Eucteniza Ausserer, 1875;Neoapachella Bond & Opell, 2002;Promyrmekiaphila Schenkel, 1950. Diagnosis. Eucteniza males can be recognized by the presence of 1-2 mid-ventral megaspines on the tibia of both legs I and II (Figs 8-10). Such mating clasper spination configuration is similar to that of Neoapachella males for leg I but are absent on leg II. Females can be distinguished from all other euctenizid genera by having what appears to be a bi-dentate cheliceral furrow and a rastellum positioned on a moderate to high rastellar mound, whereas other genera have a single row of promarginal teeth and a small patch of denticles and lack a distinct rastellar mound. Additional Eucteniza autapomorphies include a patella IV spine patch and a weakly sclerotized posterior carapace margin. General description. Small to large sized trapdoor spiders. Cephalothorax longer than wide, sloping posteriorly, lacking pubescence in most species (Fig. 2). Posterior third of carapace very lightly sclerotized (Figs 2,23,24). Thoracic groove intermediate to wide, procurved ( Fig. 2) and deep. Eyes not on a tubercle (Fig. 3). AME, PME subequal diameter. Posterior eye row slightly recurved, anterior eye row slightly porcurved (Fig. 2). Caput moderately high (Fig. 3). Carapace of ethanol preserved specimens appears most often reddish-brown, sometimes lighter. The coloration of living spiders tends to be a darker brown, however there is considerable variation in the intensity of coloration. Male coloration in most specimens is dark reddish-brown. Abdominal coloration light to dark brown, sometimes with dark mid dorsal blotch.
Sternum wider posteriorly, tapering anteriorly (Fig. 4). Posterior sigilla large and positioned mid-posteriorly nearly contiguous. Anterior margin of sigilla lacks rounded margin. Palpal endites longer than wide with numerous cuspules (Fig. 4). Labium wider than long, with numerous cuspules (Fig. 4). Chelicerae dark brown. Rastellum consists of numerous spines borne on a distinctive mound. Fangs of intermediate length and thickness. Cheliceral promargin with row of very large teeth; retromargin row comprises distinct row of large teeth interspersed with denticles.
Apical PLS article short, digitiform. Spinnerets mostly with pumpkiniform spigots with several articulated spigots interspersed on apical and median articles of PLS and the PMS (Bond and Opell 2002, fig. 3E). Two to three large, articulated spigots on apical most aspect of the PLS. PMS article robust. See Bond and Opell (2002) for more detailed descriptions of spigot types.
Anterior leg articles slender relative to posterior. Tarsi short and robust (Figs 5-6). Female scopulae long, dense, asymmetrical, extending full length of tarsus, metatarsus and half length of tibia on anterior legs; posterior legs lack distinct scopulae. Male tarsi I and II with short sparse scopulae that are restricted to the ventral surface. Basal palpal tooth and STC I -IV basal tooth elongate and bifid. STC IV with 5 or more teeth. Female anterior legs with very few ventral spines (Fig. 5). Prolateral surface of female patella III and IV covered in numerous thick short spines (Fig. 6). Preening comb on metatarsus IV absent; metatarsus, tarsus IV with ventral spines (Fig. 7). Tarsal trichobothria arranged in a wide band with interspersed setae. Spermathecae generally comprise a simple unbranched bulb that lacks an elongate base.
Male mating clasper morphology is distinctive. Tibia legs I & II swollen mid-ventrally in most species, bearing 1-2 large spines; prolateral aspect with a small to large patch of smaller, thickened, short spines. Metatarsus of leg I lacks excavation and spur. Palpal bulb simple, with spherical base, planar distally near origin of embolus. Palpal cymbium lacks dorsal spines (Fig. 11).
Distribution. Distributed primarily throughout central Mexico and Baja California ( Fig. 1) with an extension northward into Texas (United States).

Key to males
Note: as discussed by Bond (2012) keys to many mygalomorph taxa are sometimes far from optimal and thus one should not rely too heavily on species determinations using this key. Instead, knowledge of where specimen was collected and comparison to description and illustrations will likely prove more useful.

1
Tarsus swollen mid-ventrally, width wider than metatarsus (Fig. 8)  coylei and E. caprica in appearance but has more stout tarsi on leg I (Figs 8-10, 12) and fewer prolateral leg I tibial spines that are short and thick; prolateral tibial spines on the other two species are longer and thinner.
Variation. Known only from the exemplar specimen and juvenile holotype Distribution. Highly imprecise, Mexico; exemplar specimen from Mexico Distrito Federal (Fig. 1 Etymology. The specific epithet is a noun taken in apposition and is in reference to the humanoid cylon model Caprica 6, portrayed by Tricia Helfer in the remake of the science fiction series Battlestar Galactica. Diagnosis. Eucteniza caprica is similar to E. mexicana in appearance but is smaller in size and lighter in coloration, leg I tarsi are not nearly as stout (Figs 13-15, 17).
Remarks. Without doubt this species, as circumscribed herein, represents multiple species, likely cryptic. Until additional data are available (e.g., molecules) we have chosen to be conservative and strictly apply a morphological species concept as described above. Etymology. The specific epithet is a noun taken in apposition and is in reference to the highest peak on the Baja Peninsula, "Picacho del Diablo".
Diagnosis. Male Eucteniza diablo specimens can be differentiated from all other species in the genus by having, in combination, leg I tibia megaspines borne on a mid-ventral apophysis, small microspines on the ventral distal aspect of metatarsus, short ventral spines on tarsus I, and a curved tarsus III (Figs 31, 32, 35). Similar to E. zapatista but lacking retrolateral spines on male palpal tibia (Fig. 34).
Diagnosis. Male Eucteniza cabowabo specimens differ from all other Eucteniza specimens by having a very slender leg I tibia and metatarsus with thin ventral megaspines (Figs. 3-40, 42); PME's reduced in size. The single E. cabowabo female paratype lacks PME's; due to the lack of specimens it is not clear whether this is a diagnostic feature or the specimen is aberrant.
Variation. Known only from the type specimens and one other male. 3.20. Posterior sigilla large and nearly contiguous, medial anterior sigilla relatively large and positioned more towards center. Chelicerae anterior tooth row armed with 6 teeth with posterior margin comprising 4 teeth. Palpal cuspules numerous and widespread across endites; labium with 12 cuspules, LBw 1.26, LBl 0.77. Rastellum consists of 14 spines positioned on a mound. Walking legs. Leg I 12.40 long. Tarsus I with 12 widely scattered trichobothria. Legs I, II with heavy, asymmetric scopulae. PTLs 25, TBs 16. Preening combs absent. Spermathecae not with specimen, presumed lost.
Distribution. Known from La Paz and Los Cabos municipalities of Baja California Sur, Mexico (Fig. 1). Etymology. The specific epithet is a noun taken in apposition and is in reference to the type locality.

Eucteniza huasteca
Diagnosis. Male Eucteniza huasteca type specimen differs from all other Eucteniza species on the basis of its very small size, very pale yellow coloration, and by having a distinct patch of spines on the distal aspect of the palpal tibia (Figs 43,44,47); other species are typically larger in size, darker in coloration, and lack similar palpal tibia spination.

Variation.
Known only from the type specimen. Description of female. Known only from the male holotype specimen. Distribution. Known from Nueva Leon, Mexico, at La Huasteca Canyon (Fig. 1). Etymology. The specific epithet is a noun taken in apposition and is in reference to the common name used for the Mexican Liberation Army of the South (Ejército Libertador del Sur) led by Emiliano Zapata (1879-1919).
Diagnosis. Male Eucteniza zapatista leg I morphology is similar to E. diablo however it lacks tarsal spines and has a more inflated or swollen tibia (Figs 48, 49, 52). Males can be further distinguished from all other species by having an extensive patch of spines on the retrolateral distal aspect of the palpal tibia (Figs 51, 52).
Etymology. The specific epithet is a noun taken in apposition and refers to one of the groups of people that are indigenous to the area around the type locality, the Chichimeca Jonaz.
Diagnosis. Male Eucteniza chichimeca specimens can be distinguished from all other Eucteniza species by virtue of having a tibia I that is swollen distal-dorsally and with numerous small prolateral spines (Figs 53, 54, 57).
Variation. Known only from the type specimens. Description of female. Known only from the male type specimens. Distribution. Known from the type locality, Pecos River, Val Verde Co., Texas (Fig. 1). Etymology. The specific epithet is a noun taken in apposition and is in reference to the type locality in the state of Hidalgo, also used in reference to a person of noble or generous spirit.
Diagnosis. The male Eucteniza hidalgo specimen differs from all other Eucteniza species by virtue of having an extensive prolateral tibia I spine patch, ventral metatarsus microspines, and a sub-dorsal row of spines on the prolateral surface of tibia II (Figs 64-68).
Diagnosis. The male Eucteniza golondrina type specimen differs from all other species of Eucteniza by virtue of a distinct leg I morphology that includes a unique group of distal spines on the ventral surface of metatarsus I (Figs 69, 70, 73); the palpal tibia of E. golondrina also has a retrolateral distal row of spines that is lacking in all other known species (Figs 72, 73).
Diagnosis. Female specimens of Eucteniza panchovillai can be distinguished from all other known species by having spermathecae that comprise a long lateral extension and a slender stalk that curves distally into a small terminal bulb; all other species have shorter thicker stalks that do not curve distally and terminate in a larger bulb that exceeds the stalk diameter (Fig. 74).
Variation ( Diagnosis. Eucteniza rosalia can be distinguished from other known Baja California taxa for which females are known by having a pronounced spermathecal lateral base extension by having a distally squared bulb (Fig. 75) as opposed to rounded. The spermathecal stalk in E. diablo is noticeably shorter and lacks a distinct lateral basal extension (Fig. 36).
Variation. Known only from type specimen. Description of male. Known only from the female type specimens. Distribution. Known only from the type locality, Baja California Sur, Mexico.