The Ochodaeidae of Argentina (Coleoptera, Scarabaeoidea)

Abstract The Ochodaeidae (Coleoptera: Scarabaeoidea) of Argentina are revised. Previously, two species of Ochodaeinae were known from the country, both in the genus Parochodaeus Nikolajev: Parochodaeus campsognathus (Arrow) and Parochodaeus cornutus (Ohaus). An additional 7 species of Parochodaeus from Argentina are described here as new. In addition, Gauchodaeus patagonicus, new genus and new species in the subfamilyChaetocanthinae, is described. This is the first record of the subfamily Chaetocanthinae in South America. Redescriptions, diagnoses, and maps are provided for each species. We also provide a key to genera and a key to species of Parochodaeus of Argentina. With this work, the number of ochodaeid species known from Argentina is increased from 2 to 10.


Introduction
The small family Ochodaeidae includes around 100 species of scarabaeoid beetles that are found nearly worldwide. The family is most diverse in arid, sandy habitats. They are sometimes referred to as the 'sand-loving scarab beetles' (Carlson 2001), although Important characters for distinguishing species in the genus Parochodaeus are listed in Paulsen (2011) and include the armature of the head, teeth of the legs and metatrochanter, dorsal vestiture and punctation, stridulatory peg, size of the first metatarsomere, and form of the mentum. In species of Parochodaeus from Argentina the head armature, when present, consists of either horns, tubercles, or elevated carinae. The leg armature may consist of an acute tooth at the apex of the metafemora or metatibia, or the leg may be unarmed with only a broad, rounded lobe. In one species, the metatrochanter is also toothed. In one group of Parochodaeus species ('P. pectoralis-complex' sensu Carlson 1975) the first tarsomere of the metatarsus is greatly enlarged and often curved. The dorsal vestiture can vary from short bristles to a longer, "shaggy" appearance, but all Argentine species display only short to moderate length setae. Each setose puncture may have an anterior tubercle, and the surface between punctures can be tuberculate or smooth, with the tubercles presenting a tiled appearance. The presence or absence of a stridulatory peg on the abdomen is often diagnostic, and to some extent the shape of the peg can be also when present, but not with the Argentine species. The width of the clypeus is more or less uniform, but the length is often species-and sex-specific. Therefore the form of the clypeus can be strongly transverse, which is described as being short (length about 1/4 or 1/5 width), or long (length about 1/2 width). The form of the mentum is important for identification and may be strongly protuberant vertically, distinctly concave, tumid, or flat. The male genitalia are weakly sclerotized and nondescript, with informative characters restricted to the sclerotized teeth and bristles of the internal sac. Unfortunately, the internal sacs are difficult to dissect if the specimens were collected directly into alcohol or were not recently collected. Because other, more tractable characters are present to distinguish species the internal sacs were not dissected for this work. Males and females do not differ appreciably in size and are not described separately, but sexually dimorphic characters, when present, are noted in the descriptions. Color is not useful in identification of the New World Ochodaeidae because most species vary from light testaceous to dark castaneous in color.
Characters for distinguishing chaetocanthines (as defined in Scholtz et al. 1988) include: 1) metatibial spurs crenulate or pectinate; 2) metatibia compressed, not cylindrical; 3) eyes not bulging; 4) galea of the maxilla rounded. These characters are problematic with respect to the new taxon, which, although clearly allied with Synochodaeus, does not conform to half of these criteria. In particular, the metatibial spurs of the new genus are not crenulate or pectinate in the specimens examined. Because the specimens are worn, it may be possible that the crenulations are merely eroded and were originally present, but the crenulations of the mesotibial spurs are present and have not been abraded. Also, the eyes are much larger in the new genus and are as protuberant as in many ochodaeines. The compressed metatibia is not a synapomorphy for chaetocanthines because numerous species of Ochodaeinae also display this character. The rounded galea is present, perhaps representing the strongest remaining synapomorphy for Chaetocanthinae. The new genus is placed into the tribe Synochodaeini Scholtz based on its similarity to Synochodaeus species in the following characters: rounded labial palps, elongate form, tridentate protibiae, anterior clypeal margin straight, antenna with ten antennomeres, first antennomere of club not strongly hemispherical, metatrochanter not acutely produced beyond posterior margin of metafemur, and sexual dimorphism lacking. However, it differs from that genus in having a much longer clypeus that is not distinctly separated from the frons by a sulcate depression and not reflexed anteriorly. In addition, the larger metatibial spur is not crenulate, the scutellum is pointed (not rounded) apically, the labrum densely punctate/setose (not mostly glabrous), and the penultimate labial palpomeres are irregularly shaped, not cylindrical.
The original description of Arrow (1904) mentioned six syntypes, although there are ten specimens with the appropriate Wagner labels in the Natural History Museum in London. There are two pairs, (2♂, 2♀), treated as syntypes by Carlson, who labeled them numbers 1-4. One male with a BMNH type label (Syntype #1 sensu Carlson) had the genitalia dissected by Carlson, and this specimen is chosen as the lectotype. The fourth specimen (Carlson's Syntype #4) labeled "Argentina / Rio las Garzas / E. Wagner. / 1907-384" is a female accessioned three years after Arrow's publication. Because this date is after the publication date, it is not clear that Arrow studied the specimen and its syntype status is questionable.
Diagnosis. This is one of only two species in Argentina with a large tooth at the apex of the metafemur (Fig. 4), and the tooth is present in both sexes. The species can be distinguished by the presence of that tooth and a frontal horn on the head (Fig. 10).
Etymology. The specific epithet 'dentipes' is from Latin dentis "tooth" and pes "foot, leg", for the toothed metafemur, and is used a masculine adjective in the nominative singular.

Remarks.
Only seven specimens of this species are known. The specimens from Guandacol were collected at light.

Parochodaeus jujuyus Paulsen & Ocampo, sp. n.
that the paratypes were collected in flight-intercept traps, which is the most common method of collection for forest ochodaeids.  Diagnosis. The species is similar to P. dentipes in that both species have a frontal 'horn' and broad metatibiae. Parochodaeus perplexus (Fig. 12) can be separated by its lack of a large tooth at the apex of the metafemur and by the flatter mentum.
Etymology. The specific epithet 'perplexus' is Latin meaning "muddled, interwoven", because this species displays a mix of characters present in other species. The name also aptly represents how perplexed we were to find yet another new species from central Argentina. It is used a masculine adjective in the nominative singular.
Distribution ( Diagnosis. Parochodaeus phoxus (Fig. 13) is similar to P. proceripes in that it also has a large frontal horn (Figs 2). In P. phoxus, the flatter mentum lacking a longitudinal furrow and broad metatibiae will immediately separate it from P. proceripes, which has a distinctly furrowed mentum and slender metatibiae.
Etymology. The specific epithet 'phoxus' is Latinized form of the Greek 'phoxos', or "pointed, peaked", referring to the frontal horn. It is used a masculine adjective in the nominative singular.

Remarks.
Only nine specimens of this species are known. Nothing is known about the life history of these beetles. The Tucumán specimen was collected at mercury vapor light. Diagnosis. Parochodaeus proceripes (Fig. 14) is similar to P. phoxus in that it also has a large frontoclypeal horn, but the horn of this species is larger, more anterior, and is almost entirely located on the clypeus. The slender metatibiae are unique among horned species in Argentina.
Etymology. The specific epithet 'proceripes' is derived from the Latin procerus "long, slender" and pes "foot, leg", referring to the slender metatibiae, which are unusual in species with a frontoclypeal horn. The name is used a masculine adjective in the nominative singular.

Remarks.
Only the holotype is known, which is male. The specimen was collected at a light trap. Remarks. This species is relatively well represented in collections. It is surprising that such a distinctive species remained undescribed for so long. With the two small horns on the head it is immediately recognizable and cannot be confused with any other species in the genus. The life history of the species is mostly unknown. Label data indicate that many specimens were collected at light traps, which at the very least infers a nocturnal habit for the species. Diagnosis. Parochodaeus stupendus (Fig. 17) is the only species of Parochodaeus to exhibit a doubly-toothed posterior margin on the metafemur. The tooth on the ventral surface is fairly common in ochodaeids, but the second tooth on the dorsal surface is unique. The toothed metatrochanter and strongly curved metatibiae (Fig. 7) are not found in any other species in Argentina, or elsewhere. The strongly produced 'thumb' (internal apical tooth) is also species specific. The female is unknown.
Etymology. The specific epithet 'stupendus' is Latin meaning "causing astonishment or wonder". With several autapomorphies not seen in other species of the genus, P. stupendus is arguably the most wondrous ochodaeid in the New World. The name is used a masculine adjective in the nominative singular.
Distribution (Map 3). The species is known from a locality near the Bolivian border. 1 specimen examined.
ARGENTINA: SALTA: San Martín, Hito 1 (1). Temporal distribution. December (1). Remarks. This species is known only from the holotype. Like P. jujuyus, it is from the far north of Argentina. It is probable that P. stupendus will be discovered in Bolivia as well, especially because the name of the locality "Hito 1" is in reference to the "hito" or boundary post that indicates the border between Argentina and Bolivia. Gauchodaeus Paulsen, gen. n. urn:lsid:zoobank.org:act:E0452D7A-435F-4AF6-A7A8-4CC28D1F4B80 http://species-id.net/wiki/Gauchodaeus Type species. Gauchodaeus patagonicus Paulsen & Ocampo, here designated.
Diagnosis. The only known species in Gauchodaeus is an elongate ochodaeid with no elytral closing mechanism, and therefore can be quickly distinguished from the more globular Parochodaeus species with dentate elytral apices and a bituberculate propygidium. The genus is most similar to the genus Synochodaeus of southern Africa but is distinguished by the characters discussed above.
Etymology. The name is formed from gaucho, a local word commonly used to describe residents of the pampas or Patagonian grasslands, in combination with the root Ochodaeus. It is masculine in gender.
Composition. Only one species is known, herein described.

Remarks.
Nothing is known about the life history of these beetles, other than that they live in a rather inhospitable, arid part of Neuquén Province. bial spur, lack of propygidial tubercles, and simply rounded elytral apices will separate it from Parochodaeus or any other scarabaeoids.
Etymology. The species is named for the region of Patagonia, where it is found. The name is used a masculine adjective in the nominative singular.
Remarks. This species is found in Neuquén province. All known specimens were collected by Mario Gentili in a desolate and arid habitat. The method of collection is not indicated on the labels, but it is probable that the species is nocturnally active and attracted to light.