Hypothyce rayi MacGown & Hill, 2023

MacGown, Joe A. & Hill, JoVonn G., 2023, A new species of Hypothyce (Coleoptera, Scarabaeidae, Melolonthinae) from Alabama, United States of America, ZooKeys 1168, pp. 1-10 : 1

Hypothyce rayi MacGown & Hill sp. nov.

Figs 2C , 3B , 4B , 5C , 6C , 7C , 8C, F, I

Diagnosis.

Members of the genus Hypothyce can be distinguished from most Melolonthini (as defined by Evans and Smith 2020) by having an antennal club with three antennomeres; the antennae of most others in this tribe terminate in 5-7-antennomere clubs. Hypotrichia spissipes LeConte also has a club with three antennomeres but can be differentiated from Hypothyce species by the accessory tooth on the anterior tarsal claw being lobe-like instead of small and acute as in of Hypothyce and by abdominal sutures between ventrites II-IV being distinct at midline, unlike in Hypothyce where sutures at midline are indistinct due to dense setation ( Skelley 2003).

Hypothyce rayi (Figs 5C , 6C ) can be distinguished from other southeastern Hypothyce species by its generally smaller size (TL 17.3-18.7 mm as compared to 17.8-21 mm; based on a limited sample size, N = 3), pronotum and elytra with dense, lanceolate scale-like setae that mostly obscure the integument (Fig. 3B ), femora and tibiae with thickened scale-like setae on outer faces, and by being only known from longleaf pine/sandhill habitat in Hale, County, Alabama. This species is only known from three male specimens; the female is unknown.

Description.

Holotype male. Total length 17.3 mm, width 8.5 mm (measured at widest part of elytra). Elongate oval; entire body dark reddish brown, integument mostly obscured by dense, appressed, short, yellowish-white, lanceolate setae; pronotum with a distinct median stripe of yellowish-white, lanceolate setae. Head width including eyes 3.3 mm, in dorsal view head including clypeus somewhat rectangular; clypeal width 2.6 mm, clypeal margin broadly rounded and slightly convex at middle, broadly and deeply recurved, trough-like, surface with dense, appressed, short (≈ 0.25 in length), whitish, lanceolate setae that arise from strong punctures, setae projecting inward or anteriorly, setae longer than those on pronotal and elytral dorsum (≈ 0.25 mm as compared to 0.10-0.20 mm); numerous erect, longer, narrower, setae that project posteriorly interspersed between appressed lanceolate setae. Eyes large, 1.5 mm at longest point, visible dorsally and ventrally, distance between eyes (in dorsal view) approximately four times eye length; eye partially bisected anteriorly by a clypeal projection. Antenna reddish brown; with 10 antennomeres including a three-antennomere, lamellate club, length of club subequal to length of antennomeres I-VII; scape (antennomere I) pyriform with stiff, elongate setae projecting apically and along ventral edge; pedicel (antennomere II) similar in shape to scape but lacking setae; antennomeres III-V slightly longer than wide, antennomeres III and V subequal, antennomere IV slightly longer, each with few stiff, elongate setae present medially; antennomeres VIII and IX cupped, wider at base and narrowing apically.

Pronotum wider than long (6.0 mm wide, 4.1 mm long), widest in middle, posterior angles rounded; with dense, appressed, yellowish-white, lanceolate setae, setae shorter (≈ 0.10 mm in length) than on head, denser medially forming a median stripe, less dense at sides of pronotum; rim of pronotum with narrow, upward curved setae present. Scutellum heart shaped, 1.5 mm in length and 1.5 mm at widest point; edges rounded; most of the surface with dense, overlapping, appressed, lanceolate, yellowish-white setae present except along the outer rim where setae are absent, setae longer, wider, and denser than those on elytra.

Elytra 11.0 mm in length, 8.5 mm wide; with strong lateral margins; area posterior of humeri toward outer edges of elytra slightly depressed; elytral surface with dense, appressed, short, yellowish-white, lanceolate setae that mostly obscure integument, setae similar in shape and length to those on pronotum (≈ 0.10 mm in length), setae denser along midline of elytra.

Sterna with dense, overlapping, elongate yellowish-white setae. Abdominal sternites and pygidium with short, appressed, whitish yellow, lanceolate setae that mostly obscure the integument but with margins visible and with a smooth shiny area medially.

Legs: Femora reddish brown, with dense, yellowish-white, elongate, curved setae and with numerous appressed, yellowish-white, scale-like setae on anterior and ventral surfaces. Protibia reddish brown, with two strong teeth and one smaller tooth located about one third from tibial base, apical tooth strongly curved; one tibial spur present; spine-like setae present along dorsal edge; numerous elongate, erect, curved, setae present ventrally and scattered on anterior surface; numerous appressed, yellowish-white, scale-like setae on anterior and ventral surfaces. Mesotibia reddish brown, lacking large, curved teeth, but with two partial ridges located about 1/3 and 2/3 from tibial base, extending from ventral edge and angling across anterior surface toward apex of tibia, each with a row of spine-like setae present; two tibial spurs present, one about 1.5 times as long as the other; tibia widened apically and rimmed with elongate spine-like setae; spine-like setae present along dorsal edge; numerous elongate, erect, curved, setae present ventrally and scattered on anterior surface; numerous appressed, and yellowish-white, scale-like setae on anterior surface. Metabia (Fig. 7C ) similar to mesotibia except tibial spurs larger (≈ 0.10 and 0.07 mm), with longer spur widened and rounded apically, larger spur about the same length as metatarsus 1 and 2 combined. Five tarsal segments, each reddish brown, tarsus 1 ≈ 1.5 times as long as tarsi 2, 3, or 4, which are subequal in length, tarsus 5 approximately twice the length of tarsi 2, 3, or 4; tarsal claw with acute accessory tooth present, claws including accessory teeth with shallow longitudinal grooves present.

Genitalia: In lateral view parameres widened apically into a flattened club shape, upper part of club rounded rectangular and lower area in the form of a rounded triangle (Fig. 8C ); in dorsal view parameres widest at base, narrowing apically before each side splits off at which point each paramere curves away from midline, forming a gently curved oval space between them, apical tips almost touching (Fig. 8C ); in apical view each paramere appears elongate, about the same width from top to bottom, with each diverging from one another ventrally (Fig. 8I ).

Variation.

Length 17.3-18.7 mm, width 8.5-8.8 mm (N = 3). Notable variation was not observed in setation or other physical characteristics.

Type material.

Holotype, male, "Hale Co., AL, 32.9964°, -87.4932°, July 16, 2018, coll: Alan Jeon, found resting on leaf in pine scrub habitat [MEM]." Two paratypes have the same data as the holotype except collections were made on July 8, 2018, and July 21, 2018 [MEM].

Etymology.

We named this species in honor of Dr. Charles Ray, an Alabama naturalist who recognized that this collection represented a new species.

Comments.

As with the other two species of eastern Hypothyce , H. burnei and H. osburni , little is known about the natural history of H. rayi . All three species appear to be restricted to sandhill habitats, each geographically separated from one another. Thus far, only males of the three eastern species have been collected, and they were capable of flight. Although the females for these three species are still unknown, Skelley (2003) speculated that H. burnei and H. osburni were flightless, and likewise, we believe that the females of H. rayi are flightless as well. This is based on the fact that females of related H. mixta , which have been found, were flightless ( Barfield and Gibson 1975), and it would explain the apparent endemism shown by the three eastern species.

The type specimens of H. rayi were collected by Jeon in mid to late July on vegetation at night in what he described as scrub habitat in a longleaf forest. Charles Ray and MacGown made a return trip to the type locality in late August 2022, with several subsequent trips by Ray throughout the month, in hopes of finding additional specimens of H. rayi , especially females, which are unknown, but were unsuccessful in finding specimens. We believed that the habitat had changed significantly from 2018 when the beetles were collected, as the area now had a thick understory present (Fig. 9 ). The dense vegetation could be an unsuitable condition for this species (which has not been studied), and at the very least it made it difficult for us to search for the beetles. It is also likely that H. rayi has a limited time period when it is active, and that our search was simply too late in the year to find the beetle.

Figures

Figure 2. Dorsal view of clypei of A H. osburni (arrow points to the slightly concave clypeal margin) and B H. burnei C H. rayi (arrows point to the convex clypeal margin).

Figure 3. Dorsal view of A H. burnei and B H. rayi showing differences in setation.

Figure 4. Scutella of A H. burnei and B H. rayi showing differences in setation.

Figure 5. Dorsal habitus views of A H. burnei B H. osburni and C H. rayi.

Figure 6. Lateral habitus views of A H. burnei B H. osburni and C H. rayi.

Figure 7. Metatibia of A H. burnei B H. osburni and C H. rayi.

Figure 8. Male genitalia of Hypothyce: lateral view of A H. burnei B H. osburni and C H. rayi; dorsal view of D H. burnei E H. osburni and F H. rayi; apical view of G H. burnei H H. osburni and I H. rayi.

Figure 9. This photo, taken in the late summer of 2022, shows the thick understory now present at the type locality for H. rayi in Hale County, Alabama.