Anomiopsoides Blackwelder, 1944

Ocampo, Federico C., 2005, Revision of the southern South American endemic genus Anomiopsoides Blackwelder, 1944 (Coleoptera: Scarabaeidae: Scarabaeinae: Eucraniini) and description of its food relocation behavior, Journal of Natural History 39 (27), pp. 2537-2557 : 2539-2542

publication ID	https://doi.org/ 10.1080/00222930500101928
persistent identifier	https://treatment.plazi.org/id/BD71F000-7371-CB4A-FE34-476016E6FD01
treatment provided by	Felipe
scientific name	Anomiopsoides Blackwelder, 1944
status

Treatment

Anomiopsoides Blackwelder, 1944 View in CoL

( Figures 1–6 View Figure 1 View Figure 2 View Figure 3 View Figure 4 View Figure 5 View Figure 6 )

Anomiopsoides Blackwelder 1944, p 197 View in CoL .

Anomiopsis Burmeister 1861, p 62 View in CoL (nec Westwood 1837). Synonym.

Type species. Anomiopsis heteroclytus Blanchard, 1845 , here designated.

Description

Form ( Figure 1 View Figure 1 ). Color black. Body globose, sides rounded. Length 9.5–23.0 mm, width 6.5–14.5 mm.

Head ( Figures 1 View Figure 1 , 2 View Figure 2 ). Surface punctate to densely foveate; form rectangular, transverse. Frons flat or slightly depressed in middle; frontoclypeal suture present, complete, sinuous or curved. Clypeus well-developed. Clypeal surface obliquely angled downwards with respect to surface of frons or perpendicular in frontal view between clypeal medial processes. Clypeus with four anterior processes; medial processes large, parallel, convergent or divergent toward apex, with margins smooth; external process variable in shape, with internal margin smooth and external margin dentate or sinuous. Gena with external margin dentate or irregular. Eyes small, completely divided by gena, halves subequal in size. Antenna nine-segmented. Segment 1 as long as 2–6 combined. Antennal club three-segmented, elongated; first segment with a distinct glabrous area on external surface.

Pronotum. Similar in both sexes, transverse, convex; with median longitudinal sulcus variably developed. Lateral portions with a single, irregular depression. All margins beaded; posterior margin slightly sinuous.

Elytron. Globose, surface with eight striae; striae variably impressed. Pseudoepipleura present at level of 7th elytral stria.

Hind wings. Obsolete.

Venter. Proepisternum convex, shiny, sparsely setose. Prosternum with posterior margin slightly pointed. Mesosternum transverse; mesometasternal suture broadly arcuate, concave in middle. Metasternum length 4.40–4.50 times width at middle. Abdominal sternites 2–6 with sutures distinct; sternite 5 narrower in males than in females; sternite 6 strongly narrowed at middle (males and females).

Legs ( Figure 1 View Figure 1 ). Mesocoxae subparallel, slightly convergent posteriorly, separated at base. Protibia with surface punctate to foveate, with dorsomedial fringe of setae; apical margin oblique, truncate; external margin with four teeth; teeth with acute or rounded apex; protibial spur straight or curved on apex. Protarsi absent. Meso- and metatibae slender, with two dorsal and one ventral fringe of setae, setae arising from base of small denticles; apex expanded, with fringe of setae on margin. Mesotibia with two spurs, medial spur longer than external. Metatibia with one spur. Mesotarsus longer than metatarsus. Meso- and metatarsi unequal in size, becoming gracile toward apex, apex setose. Tarsal claws absent.

Male genitalia. Symmetrical, variably sclerotized.

Diagnosis

The combination of the following characters will separate Anomiopsoides from all other Scarabaeinae in the New World: clypeus with four anterior processes well-developed ( Figures 1 View Figure 1 , 2a–g View Figure 2 ); pronotum without horns or tubercles; mesocoxae not contiguous at the base; protarsi absent; mesotarsus longer than metatarsus; and hind wings obsolete.

Natural history and food relocation behavior

The genus Anomiopsoides is restricted to the Monte biogeographic province in northeastern Argentina from 26 ° to 34 ° S latitude and between 200 and 1650 m elevation. The climate in this area is temperate-arid with very little rainfall (between 80 and 250 mm per year) (Roig- Juñent et al. 2001). The northern and central regions of the Monte province receive rains in the summer, but in the south it is colder and rainfall is distributed throughout the year ( Morello 1958; Cabrera 1976). The dominant vegetation of this region is scrublands that, at times, can be very open. The landscape consists of sandy plains and plateaus and is characterized by the presence of mountain chains that define several longitudinal valleys.

Images and videos on the food relocation behavior and natural history of the tribe Eucraniini are available (see Ocampo 2003).

The behavior and biology of Anomiopsoides species are similar to those of the species of the genus Glyphoderus ( Ocampo 2004) .

Under natural conditions, the period of surface activity of A. aurita , A. biloba , A. cavifrons , and A. heteroclyta is from 9:30 to 13:00 h, and from 17:00 to 19:00 h, depending on the atmospheric and soil temperature. No nocturnal surface activity was recorded for any species of Anomiopsoides . During the observations atmospheric temperature varied between 20 and 38 ° C in the shade. All species studied prefer open, sandy or clay soils with a 20–60% vegetation cover. Anomiopsoides species , as most of the Eucraniini , have a specialization for dehydrated dung pellets. Specimens were observed carrying pellets of ‘‘cuis chico’’ ( Microcavia australis (Geoffroy Saint-Hilaire and D’Orbigny)) , ‘‘cuis’’ ( Galea musteloides Meyen ), and goat. The use of dung pellets of ‘‘vizcacha’’ ( Lagostomus maximus (Desmarest)) by A. heteroclyta was reported by Zunino et al. (1989). Specimens of A. biloba and A. heteroclyta did not take dry horse or cow dung even when it was offered, and they were not attracted to dung traps baited with fresh human or cow dung. Two species, A. biloba and A. cavifrons , use plant material as food source. Specimens of A. biloba were observed carrying small pieces of dry leaves and seeds (unidentified plant). Two specimens of A. biloba were observed ‘‘cutting’’ small leaves and seeds (that grow at ground level) using their clypeal processes. For that purpose, the beetles placed the leaf or seed in between the medial clypeal processes and pulled out with their head and pronotum. The use of plant material, including seeds, as a food source was also reported for the Australian genus Cephalodesmius Westwood ( Monteith and Storey 1981; Halffter and Edmonds 1982). These authors agreed that the use of plant material by Cephalodesmius is in response to a particular set of ecological factors, and species of this genus use leaf litter as an alternative to dung as a food source. The use of plant material as food source by A. biloba and A. cavifrons was observed occasionally, but plant material does not constitute the main food source of these species. Populations of Anomiopsoides species occur in isolated areas (usually not larger than 500 m 2). Generally, large numbers of individuals of one or two species live in the same area and are commonly associated with rodent nests or goats. The occasional use of plant material by A. biloba and A. cavifrons could be a response to the intra- and interspecific competition observed in the relatively small area of foraging. When foraging, they run on four legs, keeping their forelegs motionless and in a horizontal position with respect to the surface. Adults run in zig-zags or randomly from their burrow (apparently searching for food). To carry the food, the beetles grasp it with the foretibiae and run forward using only their middle and hind legs. This behavior is known only for members of the tribe Eucraniini . Three other methods of overland transportation (without forming a food ball) are known among dung beetles ( Halffter and Matthews 1966). In the first method, the beetles grasp the food with the forelegs and with the remaining legs walk backwards toward the burrow, carrying or dragging the food. This method was observed in Onthophagus Latreille , Copris Müller , Dichotomius Hope , Phanaeus MacLeay , and Phalops Erichson ( Halffter and Matthews 1966) . In the second method, called ‘‘butting,’’ pieces of dung are rolled (not formed into a ball) by the beetles walking forward and pushing it with their head and forelegs. This method was observed in various species of Phanaeus ( Halffter and Matthews 1966) and in Eucranium arachnoides Brullé (F. C. Ocampo, in preparation). The third method is found in the South African subgenus Scarabaeus (Pachysoma) MacLeay. Species of Pachysoma use their hind legs to grasp either dung or detritus, depending upon the species, in a pincher-like manner. Then an individual walks forwards dragging the food to its burrow. It is not clear how the beetles find their way back to the burrow (along with the shortest possible route). As described by Dacke and Warrant (2002), and Byrne et al. (2003), for the South African flightless dung beetles Scarabaeus rugosus (Hausman) , S. rusticus (Boheman) , Kheper nigroaeneus (Boheman) , and Pachylomerus femoralis (Kirby) ( Scarabaeinae : Scarabaeini) the beetles must rely on cues such as the pattern of polarized light. Beetles may use polarized light as a compass bearing that can be used to ‘‘calculate’’ the direction to the burrow. When the entrance of the burrow is reached, the beetles enter by walking forward rather than backward. Observations published by Zunino et al. (1989) regarding the above behavioral character suggested that the beetles drop the dung pellet and turn back and enter the nest walking backward while dragging the pellet. I have never observed this for any Eucraniini species (see Ocampo 2003). The burrow of Anomiopsoides is always previously dug. It is variable in depth (usually between 0.20 and 0.80 m long) and variable in slope (between 35 and 60 ° with respect to ground surface). The tunnel may be straight or curved. The depth of the burrow is apparently associated with the depth where the beetle finds a certain level of soil moisture. Burrows are sometimes bifurcated near the end. The beetles store the food at the end of the burrow, and no special chamber is prepared for it. Between three and eight dung pellets are usually stored, and each pellet is carried independently. Sexual cooperation has been observed, and it follows the same behavior as that observed for individuals. No special brood chambers were observed in burrows constructed by pairs. During the hours where there is no surface activity, it is common to observe the entrance of the burrow obscured with sand or other substrate.