Species Paraphyly and Social Parasitism: Phylogenomics, Morphology, and Geography Clarify the Evolution of the Pseudomyrmex elongatulus Group (Hymenoptera: Author Ward, Philip S. Department of Entomology and Nematology, University of California, Davis, CA 95616, USA, Author Branstetter, Michael G. U. S. Department of Agriculture, text Insect Systematics and Diversity 2022 AIFB 2022-01-25 6 1 1 31 http://dx.doi.org/10.1093/isd/ixab025 journal article 10.1093/isd/ixab025 2399-3421 7182517 Pseudomyrmex veracruzensis sp. nov. Figs. 18 and 26 Zoobank LSID: urn:lsid:zoobank.org:act: BB9D186E-1313-44F6- A9A6-F63AB60653B2 Holotype Worker. MEXICO Veracruz : Ruiz Cortínez , 13 km NE San Andrés Tuxtla , 1,055 m , 18.53387 –95.13839 ± 4 m , 5 Jun 2016 , ex dead twig of Heliocarpus , montane rainforest edge, P. S. Ward PSW17618 ( UNAM ) ( CASENT0863542 ) . Paratypes : series of workers, same data as holotype (CASC, CZUG, IEXA, JTLC, MCZC, PSWC, UCDC, USNM). Other material examined (PSWC, UCDC). Mexico : Veracruz : 10 km NNE San Andrés Tuxtla, 1,010 m (Ward, P. S.); Ruiz Cortínez, 13 km NE San Andrés Tuxtla, 1,050 m (Ward, P. S.); Ruiz Cortínez, 13 km NE San Andrés Tuxtla, 1,055 m (Ward, P. S.). Worker measurements (n = 8) . HW 0.97–1.07, HL 1.13–1.30, MFC 0.035 –0.050 , LHT 0.84–0.94, CI 0.81–0.86, FCI 0.034 –0.048 , REL 0.46–0.48, REL2 0.55–0.58, FI 0.42–0.45, PLI 0.44–0.49, PWI 0.43–0.48, MSC 2-5. Worker Diagnosis. Medium-sized species ( HW 0.97–1.07) with moderately elongate head ( CI 0.81–0.86) and eyes ( REL 0.46– 0.48); frontal carinae separated by less than basal scape width; metanotal groove moderately impressed, evident in profile; dorsal face of propodeum more or less flat, rounding into declivitous face, the two subequal in length; petiole slender, elongate ( PLI 0.44–0.49, PL/HL 0.57–0.60, PL/LHT 0.76–0.82); petiole with slight anterior peduncle, in profile the anterodorsal face flat to convex, ascending gradually to summit in posterior half of node, then rounding into more steeply descending posterior face; profemur relatively slender ( FI 0.42–0.45); hind leg relatively short ( LHT /HL 0.71–0.76). Head subopaque, densely punctulate-coriarious, the punctures becoming less dense on vertex (separated by their diameters or more). Standing pilosity sparse, absent from propodeum and mesonotum ( MSC 2–5). Medium ferrugineus-brown, with darker and rather diffuse transverse bands on anterior half of abdominal tergites 4–6 (gastric tergites 1–3); metafemur and, to a lesser extent, mesofemur infuscated. Comments. Key features of this species are the ferrugineus-brown body, with darker transverse bands on the gaster; relatively large size (worker HW 0.97–1.07); and low, elongate petiole (worker PL 0.65–0.77, worker PLI 0.44–0.49). Workers of P. veracruzensis are superficially similar to those of the Costa Rican species, P. nimbus , but can be distinguished by their shorter legs ( LHT 0.84–0.94 and LHT/HL 0.71–0.76 vs LHT 0.96–1.09 and LHT/HL 0.76–0.82 in P. nimbus ), smaller eyes ( REL 0.46–0.48 vs 0.48–0.51 in P. nimbus ), less strongly impressed metanotal groove, differently shaped petiole (compare Figs. 16 and 18 ), and lighter coloration. An index combining PL, LHT and HW also separates the two species: ( PL / LHT )/HW 0.74–0.80 versus 0.62–0.71 in Pseudomyrmex nimbus . P. veracruzensis is somewhat isolated phylogenetically, as sister to