Obtusitermes monomorphus Scheffrahn, Roisin, Wang, Bourguignon & Hellemans, 2025, sp. nov.

Obtusitermes monomorphus sp. nov. Scheffrahn Holotype. Soldier from University of Florida Termite Collection (UFTC) no. PN153. Type locality. PANAMA: Coclé, El Cope Natl. Park; 8.6790, -80.5972; 841 m asl; 30-May-2005; J Chase coll.; UFTC PN153; many soldiers and workers taken from under horse dung. Paratypes. PANAMA: Guna Yala (formerly San Blas), Kuna Rd. Stop 4; 9.3261, 78.9992; 360 m asl; 5-Jun-2010; R Scheffrahn coll.; UFTC PN1415; many soldiers and workers taken from under a decaying branch. Etymology. Named for the monomorphic soldier caste which is exclusive to Obtusitermes. Imago. Unknown. Soldier (Fig. 2, 6; Table 1). Monomorphic, small size. Head capsule reddish brown, nasus darker. Antennal articles and palps reddish brown. Head capsule pyriform from above, constricted at anterior one-third. Lateral view of head capsule convex behind antennal sockets. Vertex with two long setae at summit of convexity and four long setae at posterior half of vertex. Nasus broadly conical, upturned about 10°. Antennae with 11 articles; antennal article formula 2<3>4≤5. Mandibles with small points. Comparisons. The soldier of O. monomorphus sp. nov. differs from the major soldiers of O. panamae (Fig. 8A, B) and O. formosulus (Fig. 9A, B) in that O. monomorphus sp. nov. soldier has six long setae on the vertex while the other two species have numerous scattered long and short setae. The head capsule of O. monomorphus sp. nov. is more pyriform in dorsal view than the other two species of the genus. The soldier of O. monomorphus sp. nov. differs from the other monomorphic small nasutes of Panama in having the head capsule, antennal articles, and palps reddish brown instead of yellowish (Fig. 7). The nasus of the O. monomorphus sp. nov. soldier is more broadly conical with the exception of Coatitermes clevelandi (Figs. 7G, H). Among this group, only Obtusitermes and Atlantitermes kirbyi (Figs. 7D, E) have six long setae on the head capsule versus dozens or more on the other species. Worker (Figs. 3–6, 10; Table 2). Monomorphic. Head capsule yellowish brown; vertex with concavity behind postclypeus; postclypeus slightly inflated.Antennae with 12 articles; antennal article formula 2>3≥4=5. Mesenteron and P1 tubular, mixed segment lacking; P1 divided near middle by slight darkened constriction. Enteric valve armature very long, tubular, curved 180°; armature at both ends; EVA seating simple. Enteric valve armature composed of two rings separated by nearly 1 mm of smooth cuticle. Proximal EVA ring at the terminus of P1 consists of six triangular cushions with their apex directed distally with food stream. Each cushion contains about 20 to 30 scales terminating in short spines. Distal ring at insertion of P3 consists of six cushions alternating in pairs of triangular and elongate scaled cushions; scale texture as in the proximal ring. Left mandible with apical and first marginal teeth equal; molar prominence small; distal margin of the M1+2 forms a long, slightly concave cutting edge longer than apical tooth distance to molar prominence. Right mandible with apical tooth narrower than first marginal. Molar plates with ridges. Comparisons. The worker head capsule width of O. monomorphus sp. nov. is somewhat larger (0.95– 0.85 mm) than the major worker of O. panamae (0.64–0.78 mm, UFTC PN1076; 0.60–0.62, Snyder 1924) or the major worker of O. formosulus (0.70–0.85 mm, Cuezzo & Cancello 2009). Mandibular dentition of all three are identical. The worker hindgut of Obtusitermes spp. is unique among termites in having the P1 joined to the P3 by a very long and tubular P2 with a curvature of 180° and weak armature at both ends (Figs. 5, 10).