Balleriolus, a new termitophilous genus of Ceratocanthinae (Coleoptera: Hybosoridae) from South America and notes on termitophily in the tribe Scarabatermitini Author Sousa, Rafael Author Vaz-de-Mello, Fernando Z. text Journal of Natural History 2023 2023-11-03 57 29 - 32 1377 1395 http://dx.doi.org/10.1080/00222933.2023.2248689 journal article 284801 10.1080/00222933.2023.2248689 fed339b8-f32b-447c-9a5d-83444429dd75 1464-5262 10492238 Balleriolus gen. n. ( Figures 1A–N , 2 A–E , 3 E , 4 A, B, E, F, H, I, M, N , 5B, C ) Type species. Balleriolus howdeni sp. n. (here designated). Differential diagnosis. Balleriolus gen. n. morphologically resembles Ivieolus Howden and Gill, 1988 . On the pronotum both genera have a deep U- or V-shaped sulcus on the median posterior area, but Balleriolus gen. n. can be distinguished by the following combination of morphological characteristics ( Ivieolus morphology in parentheses): mandibles with 1 apical tooth ( Figures 1M, N , 3H ) (2 distinct apical teeth, Figure 3G ); maxillary palpus slender (robust), distal palpomere subpiriform ( Figures 1M, N , 3H , 4B ) (piriform, Figure 3B, C, G ); labium with 3 palpomeres ( Figure 3H ) (1 palpomere, Figure 3G ), palpus small and cylindrical ( Figure 3H ) (large and nearly spherical, Figure 3G ); sides of pronotum not constricted ( Figures 1 , 4A, B ) (medially constricted, Figures 3A–F , 4C, D ); posterior area of pseudoscutellum not separated from posterior border of pronotum by a margin ( Figure 4A, B ) (separated from posterior margin of pronotum, Figure 4C, D ) (see Table 2 ). Figure 1. Balleriolus gen. n. habitus. (A–C, M) B. howdeni sp. n. male, holotype; (E–H) B. howdeni sp. n. , stenogastric female, paratype; (I–K, N) B. alleni sp. n. , holotype; (A, E, I) dorsal habitus; (B, F, J) lateral habitus; (C, H, K) frontal habitus; (M, N) frontolateral habitus. (D, L) type labels. Scale bars: 1 mm. Figure 2. Balleriolus gen. n. Intermediate form female habitus. (A) dorsal habitus; (B) lateral habitus; (C) ventral habitus; (D, E) terminalia; (C) lateral; (D) frontal posterior. ans, annal aberture; gnd, gonocoxite distal piece; gnm, gonocoxite medial piece; gnp, gonocoxite proximal piece; pgy, pygidium (tergite VIII); sp7, spiracullum VII; sp8, spiracullum VIII; st7, sternite VII; tg7, tergite VII; vag, vagina. Scale bar: 1 mm. Description. Body . Length 4.5–5.5 mm ; width 1.5–1.9 mm ; body form elongated. Head . Clypeus wide, lateral margin slightly rounded and contiguous with the gena, junction slightly rounded ( Figure 1M, N ); anterior area of mandibles, labrum and palps extending anteriorly to clypeus anterior margin. Mandibles with 1 tooth, anteriorly sclerotised ( Figures 1M, N , 3H ). Maxillae with 3 slender palpomeres; distal palp subpiriform ( Figures 1M, N , 3H , 4B ). Mentum small and slightly convex ( Figure 3H ); labial palpus with 3 small and cylindrical palpomeres ( Figure 3H ). Antennae with 8 antennomeres; scape slightly flattened, longer than funicle (antennomeres III–V, Figure 1M, N ), proximal area narrow and sinuated; pedicel cylindrical; antennomere III smaller than IV–V; club composed by 3 antennomeres, distal lamella convex and smaller than proximal and medial lamella, medial lamella slenderer than others ( Figures 1M, N , 3H , 4A, B ). Thorax . Median posterior area of pronotum with a large and deep inverted U-shaped sulcus delimiting the pseudoscutellum; posterior area of pseudoscutellum convergent and not separated from posterior margin of pronotum ( Figures 1 , 4A, B ). Legs . Procoxa subcontiguous, conical ( Figure 3H ); protibia with 2 acute outer teeth; distal tooth slightly unciform; spur indistinct ( Figure 4I, J ); tarsomeres setose laterally, cylindrical and slightly expanded distally ( Figure 4I, J ); tarsomeres I and V longer than II–IV; tarsal claws simple and symmetrical. Meso- and metacoxae contiguous; meso- and metafemora slender; meso- and metatibia with 2 long and simple spurs; metatarsomeres with ventral setae more robust than the dorsal setae. Abdomen . Visible sternites conical ( Figures 1F, G , 2B, C ). Figure 3. Ivieolus genus group habitus: (A–C) Ivieolus brooksi Howden and Gill, 2000 ; (D–G) I. pseudoscutellatus Howden and Gill, 1988 (photo by Vinícius S. Ferreira and Mike Ivie); (H) Balleriolus howdeni sp. n. ; (A, D) dorsal habitus; (B, E) lateral habitus; (C, F); (G, H) ventral habitus. Figure 4. Ivieolus genus group species: (A, E, I) Balleriolus alleni sp. n. ; (B, F, J, M, N) B. howdeni sp. n. ; (C, G, K) Ivieolus brooksi Howden and Gill, 2000 ; (D, H, L, O) I. pseudoscutellatus Howden and Gill, 1988 ; (A– D) pronotum and head, dorsal habitus (details of antenna and maxillary palpus); (E–H) elytron, dorsal habitus; (I–L) protibia; (M–O) genitalia, (M) posterior view; (N) frontodorsal view; (O) dorsal view (modified from Howden and Gill, 1988). Scale bar: 0.5 mm. Figure 5. Balleriolus howdeni sp. n. (A) Serra do Rola Moça, Nova Lima, Minas Gerais State; (B, C) live physogastric female (Photo by Robson A. Zampaulo); (D) worker of Apicotermitinae (Isoptera: Termitidae ); (E) soldier of Nasutitermes sp. ( Termitidae : Nasutitermitinae ). Scale bar: 1 mm. Table 2. Comparative table for the species of the Ivieolus genus group.

Ivieolus	Ivieolus	Ivieolus	Balleriolus	Balleriolus
brooksi	inflaticollis	pseudoscutellatus	alleni sp. n.	howdeni sp. n.
Dorsal frons setae	Present	Present	Absent	Absent	Absent
Clypeus anterior margin	Sinuated	Arcuated	Emarginated	Emarginated	Emarginated
Distinct mandibular teeth	Two	Two	Two	One	One
Maxillary palpomeres I–II	Robust	Robust	Robust	Slender	Slender
shape
Maxillary palpomere III	Cylindrical	Cylindrical	Cylindrical	Cylindrical and	Flattened and
shape	and	and	and piriform	subpiriform	subpiriform
piriform	piriform
Labial palpus visible	One	One	One	Three	Three
Labial palpus shape	Large and	Large and	Large and nearly	Small and	Small and
nearly	nearly	spherical	cylindrical	cylindrical
spherical	spherical
Antennal scape	Not outwardly	Not outwardly	Not outwardly	Not outwardly	Outwardly
expanded	expanded	expanded	expanded	expanded
Pronotal sulcus shape	V-shaped	V-shaped	U-shaped	U-shaped	U-shaped
Pronotal setae	Present (10)	Present (?)	Present (8–10)	Present (4)	Absent
Pronotum median lateral	Strongly	Strongly	Weak constricted	Not	Not constricted
area	constricted	constricted	constricted
Elytral striae impression	Weak	Deep	Deep (distinct just	Indistinct	Weak (distinct just
in anterior half)	in anterior half)
Elytral distal angle	Acuminated	Acuminated	Acuminated	Acuminated	Rounded
Elytral dorsal setae	Present (8–11)	Absent	Present (2–3)	Absent	Absent
Protibia outer margin	Serrated	Serrated	Serrated	Serrated	Smooth

Etymology. The genus is named after Dr Alberto Ballerio, who has dedicated many years to the study of the taxonomy and systematics of Ceratocanthinae . The gender of the name is masculine.