Chasitermes pax, a new genus and species of soldierless termite (Termitidae, Apicotermitinae) from the island of Trinidad Author Scheffrahn, Rudolf H. Fort Lauderdale Research and Education Center, Institute for Food and Agricultural Sciences, University of Florida, 3205 College Avenue, Davie, Florida 33314, USA rhsc@ufl.edu Author Carrijo, Tiago F. https://orcid.org/0000-0001-6308-7252 Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, Rua Arcturus 03, Jardim Antares, 09606 - 070, Sao Bernardo do Campo, SP, Brazil text ZooKeys 2023 2023-01-11 1139 127 136 http://dx.doi.org/10.3897/zookeys.1139.94972 journal article http://dx.doi.org/10.3897/zookeys.1139.94972 1313-2970-1139-127 DEE0DCAA03484B4A9990A989D913651E 5B80349D09755BAEB75A9F3087D7CF92 Chasitermes Scheffrahn & Carrijo gen. nov. Type-species. Chasitermes pax Scheffrahn & Carrijo, sp. nov. Diagnosis. The combination of unsclerotized rectangular EVA cushions, a tubular extension of EVS, and a prominent spherical mesenteric tongue make C. pax unique among all Apicotermitinae genera. Description. Imago unknown. Worker. (Figs 1 - 4 ). Monomorphic. Head capsule and antennae light yellowish. Head covered with ca 50 longer (0.1 mm) setae and a few shorter ones (Fig. 1 ). In lateral view, dorsal surface of the head capsule slightly convex; postclypeus is moderately inflated. Antennae with 14 articles (formula 2>3≈4<5). Pronotum with about 20 long setae concentrated mainly at the borders and a few shorter ones. Mandibles with apical teeth very prominent; left mandible with M1 triangulate, shorter than apical; premolar process longer than M3 (Fig. 2A ). Apical tooth of right mandible as long as that of left but narrower; M1 as long as M2. Fore tibia moderately inflated (Fig. 2C ) with about a dozen thick posterior setae concentrated at the distal half; lateral and anterior surfaces with thinner long and shorter setae. Digestive tube (Fig. 3 with abbreviations) with voluminous crop; mesenteron forming half circle; mixed segment with prominent spherical mesenteric tongue. First proctodeal segment (P1) widens to maximum diameter before P2, enteric valve seating (EVS) slightly trilobed. Third proctodeal segment (P3) with long tubular extension of the EVS seating to main reservoir (Fig. 4C ) then narrowing again toward P4 (Fig. 3D ). Cuticle of EVA without sclerotization (Fig. 4A, B ) forming six rectangular cushions with about 100 scales each (Fig. 4A ). Scales proximal to P1 subrectangular, each with 5-10 creases; scales in distal one-third lacking creases, more scale-like with long fringes (Fig. 4B ). Measurements are provided in Table 1 . Table 1. Measurements (mm, N = 10) of Chasitermes pax gen. et sp. nov. workers.

-	Max.	Min.	Mean
Length of head to lateral base of mandibles	0.77	0.70	0.73
Maximum head width	0.93	0.82	0.85
Length of hind tibia	0.77	0.67	0.72
Length of postclypeus	0.25	0.18	0.21
Width of postclypeus	0.44	0.39	0.40
Length of fore tibia	0.67	0.53	0.60
Width of fore tibia	0.18	0.12	0.15
Fore tibia width:length ratio	0.30	0.21	0.25

Figure 1. Chasitermes pax gen. et sp. nov. A right lateral habitus of worker B lateral and C dorsal views of head. Figure 2. Chasitermes pax gen. et sp. nov. A mandibles (abbreviations: a = apical, m1-m3 = marginal teeth, mp = molar process, arrow = premolar process (Constantini et al. 2020) B right fore tibia. Figure 3. Chasitermes pax gen. et sp. nov. digestive tube A dorsal B right C left, and D ventral (abbreviations: C = crop, EVS = enteric valve seating, MS = mesenteron, MT = mesenteric tongue, P1-P5 = proctodeal segments). Figure 4. Chasitermes pax gen. et sp. nov. A spliced whole mount of enteric valve armature (rightmost cushion torn) B close-up of two cushions C region encompassing EVS (abbreviations as in Fig. 3 ). Remarks. The single most diagnostic character of the C. pax worker is the enteric valve armature which has unsclerotized rectangular cushions composed of creased or fringed scales. The tubular extension of the EVS in C. pax is closest to Patawatermes nigripunctatus (Emerson, 1925) but is much longer in the former and P. nigripunctatus lacks a trilobed enteric valve seating. The left mandible of C. pax has prominent premolar process closest to Patawatermes turricola (Silvestri, 1901) but it is narrower and longer in the former. Etymology. Named in honor of the collector, James A. Chase.