Eurhopalothrix, Brown & Kempf, 1961

Chaul, Júlio Cezar Mário, 2022, Redescription of Eurhopalothrix reichenspergeri (Santschi, 1923) stat. rev. (Hymenoptera: Formicidae), a Brazilian Atlantic Forest endemic species, Zootaxa 5182 (1), pp. 1-20 : 5-8

A list of the southern South American Eurhopalothrix

Eurhopalothrix bruchi Santschi, 1922

Eurhopalothrix clypeata Brown & Kempf, 1960

Eurhopalothrix depressa Ketterl et al., 2004

Eurhopalothrix lenkoi Kempf, 1967

Eurhopalothrix pilulifera Brown & Kempf, 1960

Eurhopalothrix reichenspergeri ( Santschi, 1923) stat. rev.

Eurhopalothrix speciosa Brown & Kempf, 1960

Eurhopalothrix spectabilis Kempf, 1962

Key to the southern South American Eurhopalothrix species

1 Dorsum of head, mesosoma and metasoma entirely covered on appressed squamose setae. Small species (HW 0.38–0.45) ( Fig. 3 )................................................. E. bruchi (ARG; BRA: SC, PR, SP, RJ, MG, ES, BA; PAR)

- Pilosity never as above, species either mostly glabrous having conspicuous standing setae, sparsely distributed, easily countable, forming symmetrical pairs and ground pilosity never squamose. Various sizes, usually larger than above................ 2 2 Transverse arched ridge present on face.................................................................... 3

- Transverse arched ridge absent on face.................................................................... 4

3 Transverse arched ridge on clypeal region ( Fig. 4 , A)...................................... E. clypeata (BRA: BA)

- Transverse arched ridge on frontovertexal region ( Fig. 4 , B).......................... E. depressa (BRA: SP, SC, RS) 4 Dorsum of head, mesosoma and metasoma devoid of standing setae ( Fig. 5 , A)................................................................................................. E. spectabilis (BRA: BA, MG, SP, PR, SC; PAR).

- Dorsum of head, mesosoma and metasoma having standing “pompon-like” setae ( Fig. 5 , B)......................... 5 5 Infradental propodeal lamella expanded at least in its upper portion ( Fig. 6 , A).................................... 6

- Infradental propodeal lamella small and adjunct to the curvature of the propodeal descending surface ( Fig. 6 , B).......... 7

6 Projecting setae on anterior margin of scape considerably different from those on its dorsal surface. Infradental lamella expanded across its entire length. Large species (HW 0.96)..................................... E. lenkoi (BRA: BA, ES, SP)

- Scape without differentiated setae on its anterior margin when compared to those on its dorsal surface. Infradental lamella becomes thin on its lowermost level ( Fig. 6 , A). Small species (HW 0.53–0.58)........ E. pilulifera (BOL; BRA: BA, GO)

7 Dorsum of head with three pairs of standing setae; promesonotum with two pairs (both at the mesonotal level). Eye large, easily larger than diameter of tip of pompon-like seta as seen from above ( Fig. 7 , A)......... E. speciosa (BRA: MG, RJ, SP, SC)

- Dorsum of head with nine pairs of standing setae; promesonotum with four pairs (two at the pronotum level and two at the mesonotum level). Eye small, not much larger than diameter of tip of pompon-like seta as seen from above ( Fig. 7 , B)......................................................................... E. reichenspergeri (BRA; MG, SP, SC)

With the revival of E. reichenspergeri , registers of E. gravis from southern South America which were not studied, such as that of Silva & Brandão (2014), might in fact represent E. reichenspergeri populations. Only two Eurhopalothrix species, E. clypeata and E. pilulifera , remain occurring both in the southern and in the northern portions of South America ( Fig. 8 ).

Figures

FIGURE 3. Eurhopalothrix bruchi with its unique pilosity among the Neotropical Eurhopalothrix composed of a dense cover of appressed squamosed setae. Scale bar is 1 mm.

FIGURE 4. Transverse arched carinae on head. A, carina on clypeus of Eurhopalothrix clypeata (UFV-LABECOL-000773, image by Jack Longino); B, carina on frontovertex of E. depressa (CASENT0636778, image by Jack Longino).

FIGURE 5. Presence (black arrowheads) and absence of large, spatulate setae on dorsum of body. A, E. spectabilis (UFV- LABECOL-008985); B, Eurhopalothrix reichenspergeri (UFV-LABECOL-000725).

FIGURE 6. Development of infradental lamella. A, expanded, subquadrate lamella of E. pilulifera (CASENT0618717, image by Brendon Boudinot); B, thin lamella, accompanying propodeal descending surface of Eurhopalothrix speciosa (CASENT0280767, image by Estella Ortega).

FIGURE 7. Full-face view of heads of A, E. speciosa (CASENT0280767, image by Estella Ortega) and B, E. reichenspergeri (UFV-LABECOL-010765) comparing head setation and evincing the relative size of the compound eyes by comparing the eyes with expanded tips of the specialized setae.

FIGURE 8. Eurhopalothrix species occurring in southern South America. E. pilulifera has a larger distribution, reaching Central America, which is not shown (see Longino, 2013 for that species and the remaining Neotropical Eurhopalothrix).