Amphimallon alexandri Uliana & Montreuil, 2022

Uliana, Marco & Montreuil, Olivier, 2022, A new species of Amphimallon Latreille, 1825 (Coleoptera: Scarabaeidae: Melolonthinae) from continental Greece, Zootaxa 5087 (2), pp. 372-382 : 373-381

Amphimallon alexandri Uliana & Montreuil , new species

Figs. 1–3 , 5 , 7, 9 , 11–12 , 15 –17.

Type material. Holotype “ Greece, Thessaly, Volos / NE of Portaria, Mt. Pelion / 850 m, 15.VI.2019 / leg. M. Malavasi, G. Gualdi ”, ♂ ( MUCC, temporarily deposited at MSNVE) . Paratypes: same data of the holotype, 77 ♂ ( MUCC, OMCF, VSCB, MMCC), 1♀ ( MU) .

Diagnosis

A species of Amphimallon with head and pronotum black, elytra light brown to dark brown, underside and legs dark brown to black. Pronotum and elytra sparsely setose. Setae of pronotum mostly erect, fine, hair-like, short or very short in the distal part, longer in the basal part, in particular medially. Setae of elytra erect, stiff, short, and bristlelike, except in a narrow periscutellar area, where they are longer and similar to the basal setae of pronotum.

Antennae with 9 antennomeres. Punctures of pronotum sparse, well spaced, on average parted by a distance larger than their diameter. Protibiae with external margin either sinuose, untoothed, or with teeth expressed as barely marked knobs; apical spur very short, not or barely passing the base of protarsomere 1. All tarsi short, ratio length/ width of metatarsomere 5: 2.4 – 2.8.

Description of the holotype ♂

Habitus as in Fig. 1 .

Size. 13.3 mm from the margin of clypeus to the pygidium.

Color. Head, pronotum and scutellum black, with clypeus narrowly dark brown along anterior margin. Elytra light brown. Pygidium dark brown, underside and legs dark brown to black. Antenna brown.

Vestiture. Head. Clypeus with sparse tiny setae, barely visible. Frons with short, erect setae, slightly longer on the vertex, inclined backward except near the eyes, where they are inclined forward. Pronotum ( Fig. 7 ) covered with setae on the whole dorsal surface; setae mostly erect to inclined backwards, fine, hair-like, mixed in length; short to very short setae are sparse on the whole surface, denser on sides and adpressed near the posterior angles; long, erect setae are present mostly in the basal half, especially in a broad medial area, and in a smaller medial area next to the anterior margin; all these areas scarcely defined and merging into each other. Anterior and lateral margins of pronotum with ticker, stiff setae, their length similar to the longest setae of the discal area. Scutellum with abundant short setae. Elytra with setae on the whole surface, much sparser than on pronotum, erect to inclined backwards, their length similar to the longest setae of pronotum on a small periscutellar area, where they are also denser, elsewhere shorter, stiff, bristle-like, slightly thicker than those of pronotum, but still variable in length. Epipleura with short, thicker setae, their length reaching about 1.5x the longest setae of the discal area. Pygidium with almost invisible microsetae in the basal area, with some long setae on the apical margin. Meso-metaventrum covered with dense, long, hair-like setae. Abdominal ventrites with sparse, short, adpressed setae and an irregular row of thicker, raised ones, shorter in the medial part, longer and thinner at the sides. Appendages: mesofemora, metafemora, and internal side of meso- and metatibiae longly setose.

Morphology. Head. Clypeus short, about 4.3 times as wide as long; anterior margin with a broad and shallow medial concavity; surface almost flat, with margin scarcely raised, covered by dense, shallow, regular punctures. Frons raised, forming an angle with the clypeus, bearing a blunt, entire carina. Behind the carina, the vertex appears mildly bulging, due to the presence of two shallow impressions at its sides. A tiny, scarcely marked carina is parting such impressions from eyes. Frons, vertex, and lateral impressions covered by punctures, deeper, denser, and more irregular than those of the clypeus. Pronotum ( Fig. 7 ). Covered by sparse punctures, on average spaced by more than their diameter, slightly variable in size, denser near the sides. A narrow unpunctured area is present along the midline of pronotum. Integument between punctures quite shining. Anterior angles broadly rounded and obtuse, posterior angles similar in shape, but more marked. Maximum width approximately at the middle, sides strongly converging in the distal part, subparallel, just slightly converging, in the proximal part. Base with a fine margin, sinuous, broadly protruding towards the scutellum in the medial part. Scutellum elliptical, finely and densely punctured in the medial part, smooth along the sides. Elytra covered by sparse punctures connected by dense irregular wrinkles, producing an overall confuse sculpture; epipleura marked until the external apical round. Interstriae 1, 3 and 5 slightly raised. Pygidium microreticulated, covered by dense, regular punctures. Appendages. Apical maxillar palpomere fusiform, slightly depressed dorsally, not enlarged. Antennae composed by 9 antennomeres, club 1.3 times as long as antennomeres 2–6. Protibiae ( Fig. 12 ) with external margin without well-developed teeth, an obtuse knob is marking the position of the second tooth, a second, barely recognizable knob is marking the position of the third (basal) tooth. Apical spur short, reaching the base of protarsomere 1 (view from above). All tarsomeres strongly punctured, short and thick, fifth metatarsomere 2.8 times as long as wide. Aedeagus as in Fig. 15 .

Relevant variation of male paratypes

Size. 11.3 – 14.2 mm, from the margin of clypeus to the pygidium; most specimens measuring above 13 mm, only three (ca. 4%) below 12 mm.

Color. Elytra from light brown (fig. 1, about 60% of the population) to dark brown (fig. 2, about 30% of the population), with intermediate forms. Ventrally, the pygidium and the legs may be dark brown to black.

Morphology. Unpunctured medial area of pronotum more or less visible, sometimes covered by microreticulated integument. Knobs marking the position of protibial teeth may be completely absent, with the margin sinuose and completely untoothed; extremes of variability are shown in Figs. 11–12 . Apical spur of the protibiae normally very short ( Figs. 11 – 12 ), in some specimens not even emerging from the internal angle of the protibia, normally not passing the base of protarsomere 1 (view from above), slightly longer and passing the basal third of protarsomere 1 in few specimens only.

Description of the female

Habitus as in Fig. 3 . Compared to males, the following differences are observed.

Color. Appendages brown, lighter, antennomeres 1–6 and tarsi lighter than the rest.

Vestiture. Pronotum almost glabrous, probably due to wear of setation, except for a few short setae along the distal part of the midline. Setation of elytra sparser, but longer, particularly in the internal part of the distal half.

Morphology. Body stouter, elytra broader distally, pygidium more protruding. Antennomeres 1–6 less elongate, antennal club shorter. Protibiae shorter, more dilated distally, with three rounded teeth along the external margin. Protibial spur longer. Mesotibiae and metatibiae with medial carina stronger, more prominent. Metatibia more robust, much more broadly dilated distally. Metatarsomeres 2–5 missing on both legs.

Etymology

Upon desire of his discoverer, Marco Malavasi, Amphimallon alexandri new species is dedicated to his son Alexandros David, living in Volos, Greece, not far from the collecting site of the new species.

Ecological notes

Amphimallon alexandri new species is a day-active species. On 15 June 2019, with hot, sultry, windless weather, it was observed in flight with full sun, in the late afternoon, approximately between 17.00 and 18.00, while the time of local sunset was 20.58 and that of twilight 21.31 (all hours expressed in Summer Time, UTC+3). A dense swarm of males was observed, counting hundreds of individuals, quickly and irregularly flying very close to the ground, occasionally stopping for few seconds on grasses or the bare soil, and then regaining flight. Some males have been found below masses of cow dung, presumably emerging from the ground, or digging after chemical trails of females. The collecting site ( Fig. 20 ) is a pasture surrounded by shrublands and small trees. It is remarkable that the collector, Marco Malavasi, visited the place at the same time also in the two previous and in the two following days, but no specimens of A. alexandri have been observed except those of 15 June. On the contrary, some adults of Amphimallon vernale (Brullé, 1832) have been collected during each visit, also in contemporary flight with A. alexandri new species. This site was also the object of many tens of entomological surveys by M. Malavasi during 2010–2019, without ever meeting this species.

Discussion

Amphimallon alexandri new species appear to be closely related to three Aegean species: A. arianae (described from Naxos and also known from Crete, and Izmir ( Montreuil 1999)), A. krali (from Rhodes) and A. spartanum (from Peloponnese), and is likely to form with them a monophyletic clade (see Montreuil 2000, 2002).

Amphimallon alexandri new species can be distinguished from all its closer relatives by the poor elongation of all tarsi, whose short and thick appearance represents a peculiar trait not shared by any of the similar species. Taking as a reference the metatarsomere 5, in A. alexandri new species, the ratio length/width is in the range 2.3–2.9, while it is in the range 3.2–3.6 for A. arianae , A. krali , and A. spartanum ( Figs. 9–10 ).

In addition, males of Amphimallon arianae and A. spartanum can be easily distinguished from A. alexandri new species for their protibiae bearing well-evident, fully developed lateral teeth ( Fig. 14 ), while in A. alexandri new species teeth are either completely absent or expressed in the form of barely marked, obtuse knobs ( Figs. 11–12 ).

This protibial condition is also shared by Amphimallon krali (habitus: Fig. 4 , detail of protibia: Fig. 13 ), that - besides differences on tarsi - can be distinguished from A. alexandri new species for several other characters, such as the setation of the pronotum, that is bearing long and raised setae also in its distal part (compared on Figs. 5–6 ), the finer and denser punctuation of the pronotum (compared on Figs. 7–8 ), the setation of the elytra, that is finer, not different in thickness from that of the pronotum, the reddish color of legs (dark brown to black in A. alexandri new species) and the clypeus, that is broadly lighter than the rest of the head (black as the rest of the head in A. alexandri new species, at most slightly reddish along the margin), the denser and finer punctures along the external margin of protibiae, the longer spur at their apex (protibiae compared on Figs. 11–13 ), and the different shape of the endophallus (Figs. 16–19).

As far as known, the four mentioned species have broadly disjunct allopatric ranges ( Fig. 21 ), whose extension may, however, be underestimated due to the very sporadic samplings.

The similarity between the new species and A. maevae (from Cyclades archipelago) and A. verticale (described from Syria, Asia Minor, and Corfu, precise distribution unknown) is looser. In addition to the toothed protibiae (similar to Fig. 14 ), these two species can be immediately distinct by the glabrous dorsal side.

Amphimallon alexandri new species raises to 15 the number of species or subspecies of Amphimallon so far listed for continental Greece ( Bezděk 2016). However, the alleged occurrence of A. atrum (Herbst, 1790) in Greece ( Smetana & Král 2006; Bezděk 2016), a Western and Central European species, is most likely based on an error (confirmed by A. Bezděk and D. Král, personal communication), as speculated by Mikšić (1965) about its alleged presence in Croatia ( Balthasar 1956) and Serbia, in fact never confirmed ( Gavrilović & Ćurčić 2010). The southeasternmost documented record for A. atrum appears to be a mid-19 th century specimen from Slovenian karst ( Brelih et al. 2010). Amphimallon atrum should therefore be removed from the Greek fauna.

Figures

FIGURES 15–ؘ19. Aedeagus of Amphimallon alexandri Uliana & Montreuil, new species, left lateral view (15, holotype). Endophalli in left lateral and frontal view of A. alexandri Uliana & Montreuil, new species (16–17, paratype) and A. krali Montreuil, 2002 (18–19, paratype).

FIGURE 20. Collecting site of Amphimallon alexandri Uliana & Montreuil, new species, NE of Portaria, slopes of Mt. Pelion, 850 m, photographed on 23 october 2017 (photo M. Malavasi).

FIGURE 21. Known distribution of Amphimallon alexandri Uliana & Montreuil, new species and of the most similar species.

FIGURES 1–4. Habitus of Amphimallon alexandri Uliana & Montreuil, new species (1, male, holotype; 2, male, paratype, 3, female, paratype) and A. krali Montreuil, 2002 (4, male, paratype).

FIGURES 5–6. Forebody in left lateral view of Amphimallon alexandri Uliana & Montreuil, new species (5, male, paratype) and A. krali Montreuil, 2002 (6, male, paratype).

FIGURES 7–10. Comparison between pronotal punctures of males of Amphimallon alexandri Uliana & Montreuil, new species (7, holotype, left half of pronotum) and A. krali Montreuil, 2002 (8, paratype, right half of pronotum). Not to scale. Left posterior tarsi of males of A. alexandri Uliana & Montreuil, new species (9, paratype) and A. krali Montreuil, 2002 (10, paratype).

FIGURES 11–14. Right protibia of males of Amphimallon alexandri Uliana & Montreuil, new species (11, paratype, 12, holotype), A. krali Montreuil, 2002 (13, paratype), and A. spartanum (Brenske, 1884) (14, from Sparta, Anogia).