Strumigenys caiman, Booher & Prebus & Lubertazzi, 2019

Booher, Douglas B., Prebus, Matthew & Lubertazzi, David, 2019, A taxonomic revision of the Strumigenys nitens and simulans groups (Hymenoptera: Formicidae), two Caribbean radiations of leaf litter ants, Zootaxa 4656 (2), pp. 335-358 : 338-340

Strumigenys caiman sp. nov.

( Figs. 1 & 2 )

urn:lsid:zoobank.org:act:900DA333-C7F6-4CCE-A2E4-E9D6753BEE8F

Pyramica nitens: Bolton 2000: 208 , figs. 144, 184 (misidentification).

Holotype worker: CUBA: Camagüey: Soledad, L.V., Blanco’s Woods, E.O. Wilson, #Berl., VII.20–53 [ MCZC: MCZ-ENT00644268].

Paratypes: CUBA: same data as holotype: 1 worker (MCZ-ENT00644267) [ MCZC]; 1 worker (MCZ- ENT00644269) [ LACM] .

Non-type material examined: CUBA: Camagüey: Baragua, Bates & Fairchild, # 137, 1932 (MCZ- ENT00644270) [ MCZC] .

Diagnosis. Strumigenys caiman can be distinguished from congeners in the nitens group by the dental count of six. This species is closely related to S. nitens and S. hubbewatyorum , but can be distinguished by the following additional characters: inner mandibular margin with two teeth; apex of mandibles with four teeth vertically arranged: the uppermost two are spiniform, while the lowermost are shorter and triangular ( Fig. 2c ); mandibles longer (MI 38–39 vs. 31–33 in S. nitens and S. hubbewatyorum ); antennal scape is shorter (SI 56–60 vs. 61–74); mesosoma slightly more compact (WL 2.1–2.2 times PW vs. 2.3); eye smaller, less than or equal to the maximum width of the antennal scape. The following characters separate S. caiman from S. zemi and S. convexiceps : mandibles relatively long (MI 24–29 in S. zemi and S. convexiceps ), petiolar node narrow in dorsal view, approximately half the width of postpetiole; mesosoma relatively elongate (WL 1.7–1.8 times PW in S. zemi and S. convexiceps ).

Worker measurements (n=4). HL = 0.45–0.48 (0.46); HW = 0.33–0.36 (0.34); ML = 0.17–0.18 (0.17); PW = 0.22–0.24 (0.23); SL = 0.19–0.20 (0.20); FL = 0.29–0.33 (0.31); HT = 0.30–0.33 (0.31); EL = 0.04–0.05 (0.04); TL = 2.01–2.07 (2.04); WL = 0.46–0.52 (0.49); CI = 74–75 (75); MI = 38–39 (39); SI = 56–60 (58).

Worker description. Adapted from the description of Pyramica nitens in Bolton (2000) . Mandibles in full face view and at full closure elongate-triangular and strongly tapering apically; MI 38–39. Extreme apices of mandibles alone engage, and a broad subovate gap is present between them through which the broad labral lobes are visible. Inner mandibular margin with two small conical teeth whose apices are widely separated at full closure; the first about one-third of the margin length from the base, the second about two-thirds the way along the margin. Apices of mandibles with a more or less vertical series of four teeth, the upper two longer and spiniform, the lower two shorter and triangular, giving a total dental count of six (see Fig. 2c ). Clypeus and upper scrobe margins have fine faint longitudinal striolate sculpture, traces of which are also present on the cephalic dorsum between the frontal carinae. Antennal scapes long: SI 56–60. Lateral margins of the head roughly parallel and the posterior margin shallowly concave in full-face view. Dorsum of head with elongate, spatulate setae which curve toward the midline. Compound eye small: diameter less than or equal to the maximum width of the antennal scape. In profile view, dense punctate sculpture present between the compound eye and the postbuccal impression.

Mesosoma elongate: WL 2.1–2.2 times PW. Uniformly smooth and shining. Dorsal surface of pronotum and mesonotum 4–5 pairs elongate, simple to blunt setae which shallowly curve toward the midline.

Petiolar node narrow, roughly 1/2 as broad as postpetiole in dorsal view. Postpetiole 1.75–2.10 times as broad as long. Petiolar peduncle covered in dense punctate sculpture, but dorsal surface of petiole and postpetiole smooth and shining. Dorsal surfaces of petiole and postpetiole with 2–3 pairs long, fine, tapering setae.

Six to ten basigastral costulae present only on the limbus and the extreme base of the first gastral tergite, covering less than 0.15 of the length of the first gastral tergite, the remainder of which is smooth and shining. First gastral tergite with four to five rows of four long, fine, filiform to flagellate tapering setae.

Head, mesosoma, and gaster uniformly dark reddish brown. Appendages lighter brown.

Distribution and ecology. Known from two localities in Cuba, both of which were lowland mature coastal forest in south-central Cuba ( Figure 9 ). The holotype worker and two paratypes were collected from leaf litter extracted in a Berlese funnel.

Taxonomic notes. Originally described in Bolton (2000) as S. nitens , this species differs from the original description and illustration by Santschi (1932); see Fig. 2c and the taxonomic notes for S. nitens below.

Etymology: a small ant with long mandibles armed with many slender teeth, this species is reminiscent of the crocodilians of the genus Caiman. The name is a noun in apposition.

Figures

FIGURE 1. Holotype worker of Strumigenys caiman (MCZ-ENT00644268): a) dorsal view b) profile view c) full-face view. Scale bars 0.2 mm.

FIGURE 2. Comparison of full-face view and mandibles in oblique antero-dorsal view of: a) reproduction of original Santschi (1932) illustration of Strumigenys nitens b) Strumigenys nitens (CASENT0914607) c) Strumigenys caiman (MCZ- ENT00644270).

FIGURE 9. Distribution of the species of the Strumigenys nitens group and Strumigenys economoi.