Gromphas amazonica Bates, 1870

Cupello, Mario & Vaz-De-Mello, Fernando Z., 2013, Taxonomic revision of the South American dung beetle genus Gromphas Brullé, 1837 (Coleoptera: Scarabaeidae: Scarabaeinae: Phanaeini: Gromphadina), Zootaxa 3722 (4), pp. 439-482 : 462-464

4. Gromphas amazonica Bates, 1870

Figs. 12–13 , 18, 21, 27, 31, 38, 45, 51, 56, 60, 64, 66 Type specimens: Lectotype: here designated, female (handwritten “Ega”, Bates’ handwritten “ Gromphas amazonicus Bates ”, printed on white paper bordered in black “Ex. Musaeo HWBates, 1892”, printed on red paper “ TYPE ”, “ LECTOTYPE ”, “ LECTOTYPE Gromphas amazonica Bates , Vaz-de-Mello, 2013”), MNHN, ex col. Oberthür (examined, Figs. 12 a–b). Paralectotype: 1. female (handwritten “S. Paulo Amaz.”, printed on white paper bordered in black “Ex. Musaeo HWBates, 1892”, “ PARALECTOTYPE ”, “ Gromphas amazonica Bates PARALECT , Vaz-de-Mello, 2013”); 2. female (handwritten “Pebas”, printed on white paper bordered in black “Ex. Musaeo HWBates, 1892”, “ PARALECTOTYPE ”, “ Gromphas amazonica Bates PARALECT , Vaz-de-Mello, 2013”), MNHN, ex col. Oberthür (examined). Third paralectotype, from “Upper Amazons” (Bates, 1870), not located at MNHN or BMNH.

Type locality: Tefé (former Ega), Amazonas, Brazil (type locality of the lectotype, according Article 76.2 of the Code [International Commission on Zoological Nomenclature 1999]).

Redescription: Color: Dorsum and metasternum usually entirely shiny black, dark blue ( Fig. 13 a), or dark green ( Fig. 13 c), without metallic reflections; some specimens reddish-brown ( Fig. 13 b).

Head: Margin of clypeus with four lobes ( Fig. 27 ) and folded upwardly, especially two medial lobes. Genae and frons completely granulate, including region adjacent to eyes ( Fig. 27 ). Cephalic projection a raised carina with emarginate apex in major specimens ( Fig. 31 ), and only slightly projecting with rounded apex in minor specimens.

Thorax: Pronotum globular; lateral region with dense granulation (Fig. 18), density of granulation decreasing posteromedially; posteromedian region smooth or with strongly effaced granulation ( Fig. 13 ); posterior fossae usually absent, apparent in very few specimens only as two very shallow and almost imperceptible impressions ( Fig. 43 ). Posterior margin of pronotum rounded.

Mesosternum with dense pilosity ( Fig. 52 ). Metasternum with variable density of punctation. Anteromedian angle of metasternum convex and with globose apex ( Fig. 51 ); area in front of anteromedian angle with evident setae (Figs. 18, 51).

Legs: Protibia narrower in males than in females ( Figs. 21 a–b); in ventral view, longitudinal carina with a row of tubercles in its basal half in males (Figs. 20d, 23b) and simple in females ( Fig. 23 a). Protibial spur with apex strongly expanded and curved downward ( Figs. 23 , 45 ). In males, inner apical angle of protibia with a long nonarticulated spur bearing a row of setae on its dorsal surface ( Fig. 21 b, white arrow); in females, inner apical angle only with a tuft of short setae ( Fig. 21 a). Apex of apical protarsomere with a long spiniform projection ( Fig. 45 ). Mesotarsi and metatarsi very broad and with apical tarsomeres only slightly curved apically ( Fig. 48 ). Metatibiae very broad and robust ( Fig. 41 ). Metatibial spur with apex distinctly curved ( Fig. 39 ).

Elytra: Striae very fine and, especially striae 1–4, distinctly carinulate from base to apical slope of elytra ( Fig. 38 ). Sutural margin glossy and punctate; in some specimens basal third or basal half of sutural margin with sheen and punctation extending laterally into first or second interstria (easily seen in Fig. 15 b).

Abdomen: Pygidium flat, not margined basally ( Fig. 36 ). Groove of propygidium extending to base of pygidium. Abdominal sternites smooth or sparsely punctate.

Aedeagus: Phallobase, in ventral view, with a very broad apical membranous area ( Fig. 56 c). Medial sclerite only slightly curved, almost flat, with a narrow and spiniform projection at one end ( Fig. 60 ).

Measurements: Males (18 specimens): TL: AV: 15.59; MX: 18.1; MN: 13.6; SD: 1.32. PL: AV: 13.73; MX: 15.3; MN: 13.6; SD: 1.32. PW: AV: 9.38; MX: 10.4; MN: 7.7; SD: 0.72. Females (20 specimens): TL: AV: 14.72; MX: 17; MN: 12; SD: 1.32. PL: AV: 12.93; MX: 14.4; MN: 10.5; SD: 1.12. PW: AV: 8.86; MX: 10.1; MN: 7; SD: 0.83. Total (38 specimens): TL: AV: 15.13; SD: 1.38. PL: AV: 13.31; SD: 1.09. PW: AV: 9.11; SD: 0.82.

Intraspecific variation and taxonomic discussion: Gromphas amazonica shows a wide variation in the punctation of the sutural margin of elytra and metasternum; some specimens show conspicuous punctation, while in others it is only slight. Variation is also seen in the spiniform projection of the female protarsus; most specimens have it well developed and evident ( Fig. 45 ), while some others seem to have the projections worn and consequently shortened.

Posterior pronotal fossae are usually absent in G. amazonica , but occasionally they are represented by a pair of small, almost imperceptible, punctiform pits ( Fig. 43 ). We observed these fossae only in two specimens; a small male from Itacoatiara (Amazonas, Brazil) and a large female from Afuá (Pará, Brazil) ( Fig. 13 c). Although the other specimens did not show any trace of these fossae, it is clear that this is no more than individual variation, the same occurring in G. inermis , also a species typically without posterior pronotal fossae (see more on the discussion of G. inermis ).

Although the non-articulated spur of the male protibiae is unique to G.amazonica ( Fig. 21 b), its homology with the small tubercle found in the male protibiae of the other species of Gromphas ( Fig. 23 b, white arrow) is likely (the tubercle, as the non-articulated spur, is absent in females). However, in no other species is this tubercle developed more than an almost imperceptible; in G. amazonica , the non-articulated spur is visible to the naked eye even in smaller specimens. Other unique characters of G. amazonica are (a) the elytral striae carinulate beyond midpoint of elytra ( Fig. 38 ); (b) apical protarsomere with a long spiniform projection ( Fig. 45 ); (c) mesotarsi and metatarsi very wide; (d) usual absence of metallic reflections; and (e) medial sclerite of internal sac with a spiniform projection ( Fig. 60 ). The phallobase with membranous apical area expanded in ventral view and the medial sclerite only slightly curved are characters shared in some way with G. dichroa and G. inermis , respectively, although in G. amazonica both characters are much more pronounced.

With G. aeruginosa and G. lemoinei , G. amazonica shares the elytral striae carinulate (in G. lemoinei and G. aeruginosa the carinulae are always absent in the apical half of elytra [ Fig. 37 ], while in G. amazonica the carinulae reach the apical slope of elytra [ Fig. 38 ]). Gromphas amazonica shares only with G. inermis the margin of the clypeus with four lobes ( Fig. 27 ) and folded upward; the cephalic projection emarginate apically ( Figs. 27 , 31 ); and the usual absence of posterior pronotal fossae (and their occasional presence in some specimens [ Fig. 43 ]). (See comparison with G. dichroa in the discussion of that species).

We examined a single female of G. amazonica that bears the unexpected locality of Cáceres (Mato Grosso, Brazil) in the Alto Pantanal region, about 1,000 km south of Contamana, Peru, the second southernmost point known for this species. This specimen has distinctly carinulate elytral striae and apical protarsomere with a long spiniform projection, but, unlike other G. amazonica , it has a strong green color with metallic reflections covering the entire body, especially the head and pronotum. With only one specimen known, it is impossible to say whether this condition is typical of this population of G. amazonica or just an individual variation (or even that this is the result of mislabeling). If indeed the existence of this Patanal population is confirmed, it would be a case analogous to, for example, Sulcophanaeus faunus (Fabricius, 1775) , a species widely distributed throughout Amazon Basin with small isolated populations in Paraguay and western São Paulo state (Edmonds 2000).

Comments: Bates (1870) based his description of G. amazonica on four specimens (“ I do not find any sexual difference in the four specimens I posses ”). Nonetheless, we were able to locate only three of the syntypes at the MNHN, all females; one of them (that from Tefé, former Ega) was designated by us as the lectotype of G. amazonica .

Bionomics: Figueroa et al. (2012) were the first to publish data on the natural history of G. amazonica . They report that this species is collected in pitfall traps baited with human feces in forests habitats and, in one case, several specimens were collected in a secondary forest associated with mandioca cultivation ( Manihot esculenta Crantz ). The specimens that we examined from Afuá, Pará, were also collected on human feces (Paulo R. Magno, MNRJ, personal communication). The specimens examined in this study were collected in July, August, September, November, January, February, and March.

Geographic distribution: Amazonian subregion: Amapa, Varzea, Ucayali, Madeira, and Pantanal. COLOMBIA: Amazonas: Letícia. BRAZIL: Amapá: Macapá. Amazonas: Benjamin Constant, Carauari, Eirunepé, Itacoatiara, São Paulo de Olivença, Tefé. Pará: Afuá ( Ilha do Pará), Porto de Moz (Tapara). Mato Grosso: Cáceres. PERU: Loreto: Mariscal Ramón Castilla (Pebas), Maynas (Iquitos); Ucayali (Contamana; Padre Márquez). San Martin: San Martin (El Porvenir). Ucayali: Coronel Portillo (Callería: Pucallpa; Yarinacocha). ( Fig. 66 ).

Material examined: 22 males and 26 females. BRAZIL: AMAPÁ: Macapá, BR 156 km. 14, 26.XI.1981, I. S. Gorayeb & Equipe cols.— 2 females (CEMT). AMAZONAS: Benjamin Constant, IX.1953, I. C. Lima col.— 1 male (MNRJ); Carauari, 57º28’05”S 05º40’75”W, 85 m, 19.VII.2009, L. Nichols, R. Braga & G. Schiffler cols.— 1 male and 1 female (CEMT); Eirunepé (former João Pessoa), Rio Juruá, 10.IX.1936, Zellibor-Hauff col.— 2 males and 1 female (MNRJ), 1 male and 1 female (FIOC) and 1 female (MZSP); Eirunepé, Rio Juruá, IX.1936, without collector— 1 male (MZSP); Itacoatiara, without date, Mann & Baker cols.— 1 male (BMNH); Tefé, VIII.1991, O. Roppa & P. Magno cols.— 2 females (MNRJ). MATO GROSSO: Cáceres, 10.X.2008, E. Silva col.— 1 females (CEMT). PARÁ: Afuá, Ilha do Pará, Igarapé Juntinta, XI.1995, P. Magno & C. Júlio cols.— 10 males and 13 females (MNRJ); Porto de Moz, Tapara, I.1923, J. F. Zikán col.— 1 male (FIOC); Porto de Moz, Tapara, II.1923, J. F. Zikán col.— 1 female (CEMT). COLOMBIA: AMAZONAS: Letícia, 700 ft., 23.II-02.III.1974, without collector— 1 male (CMNC); Letícia, 700 ft., Isla Sta. Sophia, 23.II-02.III.1974, J. Peck col.— 1 female (CMNC); Parque Nacional Natural Amacayacu, 90 m, 23.IX.1993, collector illegible— 1 female (CMNC). PERU: Ucayali, Coronel Portillo, Yarinacocha, 150m, 08-15.VII.2001, D. Curoe col.— 3 males and 1 female (CEMT).

Figures

FIGURE 66. Distribution map of the five species of Gromphas.

FIGURES 11 – 12. 11: Holotype of Gromphas lemoinei. 11 a) Dorsal view. 11 b) Lateral view. 11 c) Labels. 12: Lectotype of G. amazonica from Tefé (former Ega). 12 a) Dorsal view. 12 b) Labels.

FIGURES 13 – 15. 13: Gromphas amazonica Bates, 1870. 13 a) Dark blue specimen. 13 b) Reddish-brown specimen. 13 c) Dark green specimen. 14: Gromphas dichroa Blanchard, 1846. 14 a) Red-blue specimen. 14 b) Intermediate yellow-blue specimen. 14 c) Green specimen. 15: Gromphas inermis Harold, 1869. 15 a) Coppery specimen. 15 b) Dark green specimen. 15 c) Black specimen. Scale = 5 mm.

FIGURES 24 – 28. Dorsal view of head. 24) Gromphas aeruginosa (only one pair of clypeal lobes and tegument smooth adjacent to eyes). 25) G. lemoinei (same). 26) G. dichroa (clypeus truncate and strong granulation around eyes). 27) G. amazonica (margin of clypeus with two pairs of lobes; strong granulation around eyes). 28) G. inermis (same).

FIGURES 29 – 33. Frontal view of cephalic projections. 29: Gromphas aeruginosa. 29 a) Major specimen with cephalic projection extremely broad. 29 b) Major specimen with apical notch. 29 c) Worn major specimen. 29 d) Medium specimen. 29 e) Minor specimen. 30: G. lemoinei. 30 a) Major specimen. 30 b) Medium specimen. 30 c) Minor specimen. 31) G. amazonica. 32) G. inermis. 33) G. dichroa.

FIGURES 34 – 48. 34: Sixth visible abdominal sternite of Gromphas aeruginosa. 34 a) Male. 34 b) Female. 35) Margined pygidium of G. dichroa. 36) Non-margined pygidium of G. aeruginosa. 37) Elytral striae of G. aeruginosa. 38) Elytral striae of G. amazonica. 39) Curved metatibial spur of G. aeruginosa. 40) Straight metatibial spur of G. inermis. 41) Robust metatibia of G. aeruginosa. 42) Thin metatibia of G. d i c h ro a. 43) Posterior pronotal fossae present in some G. i n e rm i s. 44) Antennal club of G. dichroa. 45) Protarsus and expanded protibial spur of G. amazonica. 46) Protarsus and straight protibial spur of G. aeruginosa. 47) Metatarsus of G. dichroa with apical tarsomere strongly curved. 48) Metatarsus of G. aeruginosa with apical tarsomere only slighty curved at apex.

FIGURES 49 – 52. Anteromedian angle of metasternum. 49) Gromphas dichroa. 50) G. inermis. 51) G. amazonica. 52) G. aeruginosa (arrow indicates median carina of mesosternum).

FIGURES 21 – 23. Protibiae. 21: Dorsal view of protibia of Gromphas amazonica. 21 a) Female. 21 b) Male (arrow indicates non-articulating spur). 22) Ventral view of female protibia of G. aeruginosa. 23: Ventral view of protibia of G. inermis. 23 a) Female. 23 b) Male (white arrow indicates tubercle of inner apical angle and blue arrow indicates row of tubercles on ventral carina of protibia).

FIGURES 53 – 56. Schematic drawings of aedeagi (a—dorsal view, b—lateral view, c—ventral view; dashed lines delimit ventral groove). 53) Gromphas aeruginosa. 54) G. dichroa. 55) G. inermis. 56) G. amazonica.

FIGURES 57 – 62. Schematic drawings. 57 – 61: Medial sclerite of internal sac. 57) Gromphas aeruginosa. 58) G. lemoinei. 59) G. inermis. 60) G. amazonica. 61) G. dichroa. 62) Internal sac of G. aeruginosa (TE = temones; MS = medial sclerite; AS = apical sclerites).