Rhizotrogus bentelrhianus Sparacio, Muscarella, Di Giulio & Ruzzier, 2025

Sparacio, Ignazio, Muscarella, Calogero, Di Giulio, Andrea & Ruzzier, Enrico, 2025, Description of a new Rhizotrogus Latreille, 1825 (Scarabaeidae, Melolonthinae), from the Island of Pantelleria (Sicily Channel, Italy), Biodiversity Data Journal 13, pp. e 154423-e 154423 : e154423-

Rhizotrogus bentelrhianus Sparacio, Muscarella, Di Giulio & Ruzzier sp. nov.

Materials

Type status: Holotype. Occurrence: recordedBy: Enrico Ruzzier; individualCount: 1; sex: male; lifeStage: adult; preparations: dry mounted; occurrenceID: 38C26D2D-8967-50DC-A0D4-6FBA03582E56; Taxon: scientificName: Coleoptera ; family: Scarabaeidae ; genus: Rhizotrogus ; specificEpithet: bentelrhianus ; taxonRank: species; nomenclaturalCode: ICZN; Location: island: Isola di Pantelleria; country: Italy; countryCode: IT; stateProvince: Siciliy; county: Trapani; locality: Southeastern slopes of Monte Gibelè, contrada Dietro l’isola ; decimalLatitude: 36.777243; decimalLongitude: 12.025494; geodeticDatum: WGS 84; coordinateUncertaintyInMeters: 0.01; Event: eventDate: 2024-03 - 07 / 09; year: 2024; month: 03; day: 07-09; Record Level: institutionCode: Museo civico di Storia naturale Giacomo Doria ( MCSN)

Type status: Paratype. Occurrence: recordedBy: Enrico Ruzzier; individualCount: 33; lifeStage: adult; preparations: dry mounted; occurrenceID: 495D1629-4D7A-54F5-816C-B8DA88D8ABC3; Taxon: scientificName: Coleoptera ; family: Scarabaeidae ; genus: Rhizotrogus ; specificEpithet: bentelrhianus ; taxonRank: species; nomenclaturalCode: ICZN; Location: island: Isola di Pantelleria; country: Italy; countryCode: IT; stateProvince: Siciliy; county: Trapani; locality: Southeastern slopes of Monte Gibelè, contrada Dietro l’isola ; decimalLatitude: 36.777243; decimalLongitude: 12.025494; geodeticDatum: WGS 84; coordinateUncertaintyInMeters: 0.01; Event: eventDate: 2024-03 - 07 / 09; year: 2024; month: 03; day: 07-09; Record Level: institutionCode: 1 ABCB; 1 BMNH; 12 CMPC; 1 IECA; 12 ISPC; 2 MCSNG; 1 MRPC; 1 MUPC; 1 MZUP; 1 NMPC

Type status: Paratype. Occurrence: recordedBy: Enrico Ruzzier; individualCount: 5; lifeStage: adult; preparations: stored in 96 % EtOH; occurrenceID: 9B169CD8-457C-50EA-9E5D-537D611C69FF; Taxon: scientificName: Coleoptera ; family: Scarabaeidae ; genus: Rhizotrogus ; specificEpithet: bentelrhianus ; taxonRank: species; nomenclaturalCode: ICZN; Location: island: Isola di Pantelleria; country: Italy; countryCode: IT; stateProvince: Siciliy; county: Trapani; locality: Southeastern slopes of Monte Gibelè, contrada Dietro l’isola ; decimalLatitude: 36.777243; decimalLongitude: 12.025494; geodeticDatum: WGS 84; coordinateUncertaintyInMeters: 0.01; Event: eventDate: 2024-03 - 07 / 09; year: 2024; month: 03; day: 07-09; Record Level: institutionCode: Museo civico di Storia naturale Giacomo Doria ( MCSN)

Type status: Paratype. Occurrence: recordedBy: Enrico Ruzzier; individualCount: 1; lifeStage: adult; preparations: dry mounted; occurrenceID: 2096A656-C77B-57B2-8E5F-F7AF0379C11B; Taxon: scientificName: Coleoptera ; family: Scarabaeidae ; genus: Rhizotrogus ; specificEpithet: bentelrhianus ; taxonRank: species; nomenclaturalCode: ICZN; Location: island: Isola di Pantelleria; country: Italy; countryCode: IT; stateProvince: Siciliy; county: Trapani; decimalLatitude: 36.759208; decimalLongitude: 12.019939; geodeticDatum: WGS 84; coordinateUncertaintyInMeters: 0.01; Event: eventDate: 2024-03 - 08; year: 2024; month: 03; day: 08; Record Level: institutionCode: NMPC

Type status: Paratype. Occurrence: recordedBy: Ignazio Sparacio; individualCount: 1; lifeStage: adult; preparations: dry mounted; occurrenceID: 7E3B57CE-4B0A-553C-A35D-BBA015CBEB31; Taxon: scientificName: Coleoptera ; family: Scarabaeidae ; genus: Rhizotrogus ; specificEpithet: bentelrhianus ; taxonRank: species; nomenclaturalCode: ICZN; Location: island: Isola di Pantelleria; country: Italy; countryCode: IT; stateProvince: Siciliy; county: Trapani; locality: Montagna Grande ; Event: eventDate: 1995-05 - 01; year: 1995; month: 5; day: 01; Record Level: institutionCode: ISPC

Type status: Paratype. Occurrence: recordedBy: S. Costa, M. Lo Valvo and G. Mascarello; individualCount: 1; lifeStage: adult; preparations: dry mounted; occurrenceID: 17A46CAD-882D-5CE1-88A1-B896037E5F77; Taxon: scientificName: Coleoptera ; family: Scarabaeidae ; genus: Rhizotrogus ; specificEpithet: bentelrhianus ; taxonRank: species; nomenclaturalCode: ICZN; Location: island: Isola di Pantelleria; country: Italy; countryCode: IT; stateProvince: Siciliy; county: Trapani; locality: Lago di Venere ; Event: eventDate: 2022-03 - 01; year: 2022; month: 03; day: 01; Record Level: institutionCode: CMPC

Type status: Paratype. Occurrence: recordedBy: E. Ratti; individualCount: 1; lifeStage: adult; preparations: dry mounted; occurrenceID: 17A46CAD-882D-5CE1-88A1-B896037E5F77; Taxon: scientificName: Coleoptera ; family: Scarabaeidae ; genus: Rhizotrogus ; specificEpithet: bentelrhianus ; taxonRank: species; nomenclaturalCode: ICZN; Location: island: Isola di Pantelleria; country: Italy; countryCode: IT; stateProvince: Siciliy; county: Trapani; locality: Montagna Grande ; Event: eventDate: 1985-05 - 04; year: 1985; month: 05; day: 04; Record Level: institutionCode: MSNVE

Type status: Paratype. Occurrence: recordedBy: E. Ratti and G. Rallo; individualCount: 1; lifeStage: adult; preparations: dry mounted; occurrenceID: 17A46CAD-882D-5CE1-88A1-B896037E5F77; Taxon: scientificName: Coleoptera ; family: Scarabaeidae ; genus: Rhizotrogus ; specificEpithet: bentelrhianus ; taxonRank: species; nomenclaturalCode: ICZN; Location: island: Isola di Pantelleria; country: Italy; countryCode: IT; stateProvince: Siciliy; county: Trapani; locality: M. Gibele ; Event: eventDate: 1984-05 - 03; year: 1984; month: 05; day: 03; Record Level: institutionCode: MSNVE

Description

Body length, including the head and pygidium, was 16.9 mm (Fig. 1 A). Dorsal side brown with reddish pronotum. Antennae, legs and ventral side light brown; scutellar shield, suture and margins of elytra, apex of femora and tarsomeres blackened. The whole head is densely and irregularly punctured and punctures often merge; the clypeus is subtrapezoidal in the dorsal view, margins are narrowly raised and the anterior margin is slightly indented at the middle. Frontoclypeal suture distinct, subrectilinear, slightly raised. Clypeus and frons with tiny, raised, microsetae; head margins with moderately long, erect setae. Antennae 10 – segmented, 1 st antennomere clavate, 0.52 × as long as antennomeres 2–7 with a row of long, dense setae on the posterior edge, 2 nd subtriangular with dilated apex, 3–4 short and subrectangular, 5 th short with slightly protruding anterior edge, antennal club 3 - segmented, 2.1 × as long as antennomeres 2–7. Pronotum subtrapezoidal, 1.8 × as wide as long, with maximum width in the basal third, sides regularly rounded and crenulated, anterior angles obtuse, posterior angles obtuse, not protruding, posterior margin protruding backwards towards the middle. The surface is glabrous, except for long setae along the anterior and lateral margins, microreticulated with sparse and simple punctures (interpunctural distance 2 to 4 times the punctural diameter); the anterior and basal beads are complete and flattened. Scutellum subtriangular, 1.3 × as wide as long, with fine sparse punctures, partially covered by dense and long setae. Elytra elongate, 1.3 × as wide as long, broadest in the distal half, angled in the pre-apical region, humeral callus distinct; 1 st interstria very widened at the base, 1 st and 2 nd stria raised and well evident interstriae, 3 rd stria obsolete; surface glabrous, with long setae only along the lateral and apical margins; surface microreticulated with punctures deep, dense and sometimes confluent. Integument shiny and covered by fine microreticulations with deep and sparse punctures. Propygidium with sparse micropunctures; pygidium with medium-sized and sparse, large and simple punctures (interpunctural distance 3 to 6 times the punctural diameter). Abdomen with ventrites hollow in the middle with very small and sparse punctures. Anterior tibia 3 - toothed, proximal tooth weak, distal tooth slightly protruding. Posterior tibiae subrectilinear, transversal carina located at approximately half the tibial length, with six teeth on the dorsal margin. The first three tarsi of the forelegs visibly notched along the inferior – lateral margin (4–5 denticles) with the distal denticle and were much more developed (Fig. 3 A); the metatarsus was 1.4 × as long as the metatibia. Claws distinctly curved, with an elongated basal denticle. Aedeagus (Fig. 3 H) with the distal third of parameres narrow and elongated; apex very pointed in lateral view. Endophallus (Fig. 3 G) with rounded and poorly-developed posterior portion and two bulges (diverticules) barely distinct from the main body at sides of the ejaculatory ductus; ventral raspulae very developed, the lateral-dorsal ones smaller, the surface between the ventral and lateral dorsal raspulae is rough and with large punctures.

Variability

Compared with the holotype, the male paratypes do not show substantial morphological variation. The total length varies from 15.8 to 18.2 mm, with posterior tibiae bearing 5 - 8 teeth on the dorsal margin. The two female paratypes (Fig. 1 B) have total body lengths of 16.3 and 16.5 mm; pronotum transverse (1.8 × wider than long) and stouter elytra (1.2 × longer than wide); elytra with a rougher surface; antennae and tarsi shorter: antennal club 3 – segmented approximately as long as the antennomeres 2–7, metatarsus 1.1 × as long as the metatibia; propygidium and pygidium microreticuled with medium-size sparse and deep punctures (Fig. 3 D).

Diagnosis

Rhizotrogus bentelrhianus sp. nov. is characterised by glossy integuments, bicolour colouration with a brick-red pronotum and yellow elytra (Fig. 1 A and B), a clypeus feebly recessed on the anterior edge, a pronotum that is regularly rounded with the posterior edge distinctly bisinuate and protruding anteriorly, posterior angles protruding, shorter and sparser anterior edge bristles, elytral interstria 3 and 4 scarcely evident and protarsomeres 1–4 distinctly denticulate on the infero-lateral edge (Fig. 3 A). The aedeagus is narrower and pointed anteriorly (Fig. 3 H). Rhizotrogus pallidipennis is a uniformly brown ‒ yellow or red ‒ brown species that possesses matt integuments, especially on the pronotum (see Baraud (1977), Baraud (1985), Baraud (1992); Fig. 1 C and D); the anterior margin of the clypeus is distinctly hollow in the centre, the pronotum is more angular on the sides with the posterior edge less sinuate, posterior angles rounded and not protruding, punctures larger and more superficial, bristles of the anterior edge long and dense, elytra regularly rounded at the apex with punctuation smaller and sparser and, especially in Spanish samples, interstria 3 and 4 distinctly raised and evident. The denticulation of the inferior-lateral edge of the first three tarsomeres of the forelegs is slightly prominent in the first two (with 3–4 denticles) and is often absent in the 3 rd (Fig. 3 B and C); the punctuation of the pygidium is coarser and denser (Fig. 3 E and F). The aedeagus is more dilated in the anterior third and less pointed at the apex (Fig. 3 I). A broad variability in the endophallus morphology was reported for R. pallidipennis ( Martín Piera and Coca Abia 1992, Coca-Abia and Martín-Piera 1998), particularly in the development of ventral raspulae which are constantly well developed in R. bentelrhianus n. sp.

These morphological differences are confirmed through comparisons between R. bentelrhianus n. sp. and R. pallidipennis from Algeria, Morocco and Spain. The type material of taxa previously considered synonyms of R. pallidipennis from North Africa was also examined (Fig. 1 C and Fig. 2 A-C). Many of these synonyms have long been recognised. Reitter (1902) synonymised R. vexator from Menorca with R. lepidus , also from Menorca. Baguena Corella (1967) regarded R. anachoreta (with R. signatitarsis as its synonym) and R. lepidus ( = vexator ) as valid taxa, but noted that R. lepidus is " Extraordinariamente afin a anachoreta ... ". Baraud (1971), after examining numerous topotypical materials, considered R. anachoreta from southern Spain (Malaga) to be synonymous with R. pallidipennis (see also Peyerimhoff (1945)). For the European fauna, Baraud 1977 and Baraud 1992 reported R. areolus from Spain and Portugal, R. lepidus ( = vexator ) endemic to the Balearic Islands and R. pallidipennis for the Iberian Peninsula ( = anachoreta ; = signatitarsis ). For the North African fauna, Baraud (1985) reported R. pallidipennis ( = anachoreta ) in Algeria and Morocco (in addition to the Iberian Peninsula) and R. phidias ( = occidentalis ), described for Algeria, in Morocco. Rhizotrogus lepidus was synonymised with R. pallidipennis by Martín Piera and Coca Abia (1992). Coca-Abia (1995), through examination of the type (see Fig. 2 C), also considered R. gulosus from Algeria to be synonymous with R. pallidipennis . Later, through further examination of typical material, Coca-Abia and Martín-Piera (1998) included R. areolus amongst the synonyms of R. pallidipennis . Finally, Montreuil (1997) attributed the populations from Menorca described as Amphimallon menorcanum to R. pallidipennis .

All synonyms of R. pallidipennis (see Smetana and Král 2006 and Bezděk 2016) are given in Table 1 .

Comparison material

Rhizotrogus pallidipennis Blanchard, 1851

ALGERIA • 1 specimen; Museum Paris / pallidipennis type … / TYPE / TYPE; male; MNHN. • 1 specimen; ………… / gulosus Fairm. / TYPE / TYPE / Museum Paris Coll. Reiche; LECTOTIPO / Rhizotrogus gulosus Fairmaire, 1860 / Coca Abia, det. 1993 / Prep. Genital n. 878 M Balsamo Canada M. M. Coca Abia; MNHN. • 1 specimen; Algeria; Rh. Phidias m. Type; coll. Reitter; Holotypus 1901 / Rhizotrogus (s. str.) Phidias Reitter ; HNHM. • 1 specimen; pallidipennis Sidi bel Abbes; NHMB.

MOROCCO • 1 specimen; Mogador (Escalera); Mogador / Museum Paris - Coll. Ph. François - Coll. L. Bedel 1922 / Rhizotrogus occidentalis Esc : Co-typo / PARATYPE / Paratype - Rhizotrogus - occidentalis Escalera 1914 / MHNH - Paris EC 15353 (Fig. 2 D). • 1 specimen; Moyen Atlas, Azrou Ifrane area; 26 Apr. 2014; legit O. Boilly, JMPC. • 3 specimens; MA cent. Moyen Atlas, 11 Km NW Ifrane, Ifrane NP, okraj lesa Quercus , 33 ° 34 ’ 26.4 N, 5 ° 12 ’ 13 ” W; 6-7. V. 2015 leg. David Frank, IECA. • 1 specimen; Ifrane 6 km NWW; 6. v. 2015, 33 ° 33 ’ 38 ” N, 5 ° 10 ’ 57 ” W, lgt. Ondřej Konvička, IECA.

SPAIN • 8 specimens; Puente de la Sierra, Jaén; 31 Dec. 2013; legit M. López; ISPC (Fig. 2 C). • 3 specimens, Ayora (Valencia); 8 Nov 1979; legit J. J. L. Colon; 1 in MZUP and 2 in CMPC.

Etymology

The specific name “ bentelrhianus ” is derived from the Latinisation and masculinisation of the ancient Arabic name of Pantelleria Island: Bent El-Rhià “ Daughter of the wind ”.

Distribution

Rhizotrogus bentelrhianus sp. nov. is known only from Pantelleria Island (Trapani, Sicily Channel, Italy).

Biology

This species is active from early March until the beginning of May, at both low (Lago di Venere) and high altitudes on Pantelleria: Monte Gibelè, Calca del Fillio 600 m a. s. l.; Montagna Grande 800 m a. s. l. ( Perazzini 1987, Ratti 1987, Arnone et al. 1995, Ballerio et al. 2011). Notably, the phenology of R. pallidipennis , which is based primarily on observations of Spanish populations, appears to span almost the entire year, with a relatively high demographic concentration in the late winter and early spring months ( Coca-Abia and Martín-Piera 1998, López-Colón 2000). Given our observations, R. bentelrhianus seems to be crepuscular, with males and females emerging simultaneously from the native Mediterranean scrub (Fig. 4 A and B); emergence takes place between 6.30 and 7.00 p. m. CET. Once in the air, the beetles disperse in hovering flight amongst the canopy of the vegetation itself. Occasionally, the species has been recorded under stones, where it retreats during the day. The species did not respond to UV light. Rhizotrogus bentelrhianus has also been observed by one of the authors ( ER) while feeding on leaves of Cistus sp. ( Cistaceae ) at night (Fig. 4 C).

Rhizotrogus bentelrhianus Sparacio, Muscarella, Di Giulio and Ruzzier , sp. nov.

Distribution

Sicilian Channel: Pantelleria Island (Endemic).

Figures

Figure 1. Rhizotrogus bentelrhianus sp. nov. from Sicily, Pantelleria Island (Trapani, Sicily Channel), south-eastern slopes of Monte Gibelè, contrada Dietro l’isola. A holotype, male (body length 16.9 mm); B Paratype, female (body length 16.5 mm); C Rhizotrogus pallidipennis, type from Algeria, MNHN; D Rhizotrogus pallidipennis, male, from Spain, Puente de la Sierra, Jaén (body length 17.2 mm).

Figure 2. A Rhizotrogus gulosus, lectotipo (synonym of R. pallidipennis) from Algeria, MNHN; B Rhizotrogus occidentalis Escalera 1914 from Mogador, paratype (synonym of R. pallidipennis); C Rhizotrogus phidias, holotype (synonym of R. pallidipennis) from Algeria, HNHM; D Rhizotrogus pallidipennis from Algeria, Sidi bel Abbes, NHMB (these latter specimens most probably belong to a different species).

Figure 3. Rhizotrogus bentelrhianus sp. nov.: A hind tarsomeres in lateral view; D pygidium in dorsal view; G endophallus (vr = ventral raspulae; ldr = latero-dorsal raspulae; t = tigilla); H lateral and dorsal view of the aedeagus. Rhizotrogus pallidipennis from Spain: B hind tarsomeres in lateral view; E pygidium in dorsal view; I lateral and dorsal view of the aedeagus. Rhizotrogus pallidipennis from Morocco: C hind tarsomeres in lateral view; F pygidium in dorsal view.

Figure 4. Rhizotrogus bentelrhianus sp. nov.: A Paronarmic view of the collecting habitat on Monte Gibelè, contrada Dietro l’isola; B Detail of the location where most of the specimens were collected; C Male of R. bentelrhianus feeding on Cistus sp. leaves during the night.