Rhopalothrix isthmica (Weber, 1941)

Guerrero, Roberto J., Grajales-Andica, Andres F., Fernandez, Fernando, Tocora, Maria C., Fiorentino, Gianpiero & Garcia, Delly R., 2024, The ants of the genus Rhopalothrix Mayr, 1870 (Hymenoptera, Formicidae, Myrmicinae) in Colombia, ZooKeys 1191, pp. 129-150 : 129

Rhopalothrix isthmica (Weber, 1941)

Figs 2 , 6

Worker measurements

(N = 8). MdL 0.28-0.3, MdbW 0.08-0.09, ClyL 0.14-0.19, ClyW 0.4-0.43, HL 0.51-0.53, HW 0.54-0.59, WL 0.51-0.56, PrnW 0.29-0.32, PetL 0.23-0.3, PpetL 0.12-0.15, PetW 0.16-0.17, PpetW 0.28-0.31, T4L 0.49-0.55, GL 0.55-0.58.

Geographic range.

Colombia, Honduras, Guatemala, Panama. In Colombia, this species is known from Antioquia, Bolívar, Santander and Sucre.

Examined material.

Colombia • 1 worker; Antioquia, Amalfi, cañon del Porce, La Cancana ; 6.76667°N, 74.91667°W; 1000 m a.s.l.; 30 Jul. 1997; F. Serna leg.; ex sifted leaf litter mini-Winkler, low vegetation (stubble); MEFLG 11112. • 1 worker; Bolívar, SFF Los Colorados, La Yaya; 9.92611°N, 75.10583°W; 280 m a.s.l.; 3-5 Jul. 2001; ex sifted leaf litter, dry forest; IAvH-E-263435. • 3 workers; La Guajira, Dibulla, Bello Horizonte, rio Canas ; 11.25687°N, 73.44852°W; 6 m a.s.l.; 12 Oct. 2015; ex sifted leaf litter, dry forest; IAvH-E-172164. • 3 workers; La Guajira, Dibulla, Alto San Jorge, rio Canas ; 11.218°N, 73.428°W; 73 m a.s.l; 12 Oct. 2015; ex sifted leaf litter, dry forest; IAvH-E-172162, IAvH-E-172163, IAvH-E-172165. • 1 worker; Santander, Rionegro, Vereda Galapagos, Km 32 vía al mar, C.I. La Zuiza; 7.370278°N, 73.17762°W, 537 m a.s.l.; 2020; J.M. Montes leg.; CTNI 8304. • 2 workers; Santander, Puerto Wilches, Platero; 7.3483°N, 73.8960°W; 28 m a.s.l.; 10-15 Nov. 2021; ex sifted leaf litter Winkler No. 4; L. Perez leg.; CBUMAG:ENT:35949. • 1 worker; Santander: Puerto Wilches, Vereda Puente Sogamoso; 7.30537°N, 73.82779°W; 87 m a.s.l.; 22 Jul. 2022; L. Velázquez leg.; IAvH-E-226990. • 14 workers; Santander, Puerto Wilches, Vereda Centro, 7.32972°N, 73.84256°W; 88 m a.s.l.; 8 Jul. 2022; L . Arcila leg; ex sifted leaf litter, riparian forest; IAvH-E-226992, IAvH-E-226993, IAvH-E-226994, IAvH-E-226995, IAvH-E-226996, IAvH-E-232292, IAvH-E-233744, IAvH-E-238973, IAvH-E-238974, IAvH-E-238975, IAvH-E-238976, IAvH-E-243661, IAvH-E-243688. • 1 worker; Santander: Puerto Wilches, Vereda San Claver ; 7.34831°N, 73.76817°W; 93 m a.s.l.; 8 Jul. 2022; C. Quevedo-Vega leg.; ex sifted leaf litter, riparian forest; IAvH-E-226997. • 1 worker; Santander: Puerto Wilches, Vereda San Claver; 7.34792°N, 73.76817°W; 77 m a.sl.; 8 Jul. 2022; C. Quevedo-Vega leg.; ex sifted leaf litter, riparian forest; IAvH-E-226998 .

Natural history.

Rhopalothrix isthmica workers inhabit dry forest in northern Colombia and both in open grassland and riparian forest in eastern Colombia. In the latter it is a relatively abundant species, being found in 8 of 20 MiniWinkler litter samples. Rhopalothrix isthmica populations have an elevational distribution from near sea level to 1000 m.

Comments.

The morphology of the workers matches the diagnostic characters of R. isthmica , including HW 0.57-0.61 (N = 6) recorded by Longino and Boudinot (2013). In the workers of populations from La Guajira (northern Colombia), the portion of the lamella ventral to the propodeal tooth (infradental lamella) is relatively straighter on the outer margin than described by Longino and Boudinot (2013).

Figures

Figure 2. Distribution map of Rhopalothrix species in Colombia.

Figure 6. Rhopalothrix isthmica worker (IAvH-E- 172166) A full-face view B lateral view C mandible distinguishing the teeth of the apical fork; drawing inserted showing the arrangement of the teeth of the apical fork of the mandible D dorsal view. Scale bars: 0.3 mm.