Strumigenys moreauviae, Booher, 2021

Booher, Douglas B., 2021, The ant genus Strumigenys Smith, 1860 (Hymenoptera: Formicidae) in western North America North of Mexico, Zootaxa 5061 (2), pp. 201-248 : 237-239

Strumigenys moreauviae sp. nov.

Figure 41

Distribution. USA; New Mexico

Holotype worker: USA, New Mexico, Sandoval County, Coronado Island in Rio Grande , 35.331059 - 106.55382 ± 1000 m, 24 May 1999, 1544 m, pitfall trap, Collector E.R. Millard, Site 10PB4. unique specimen identifier (casent0799753) [transferred from CWEM to CUIC].

Holotype worker measurements: HL = 0.585; HW = 0.408; ML = 0.099; PW = 0.256; SL = 0.323; FL = 0.339; HT = 0.286; EL = 0.045; WL = 0.562; CI = 69.7; MI = 17.1; SI = 79.2.

Diagnosis. Of western species, S. moreauviae shares a similar dentition pattern with S. chiricahua and S. reliquia ( Ward, 1988) (tooth one and four of similar size and much shorter than similarly long teeth two, three, and five) but can be distinguished from these two species by head pilosity. Strumigenys moreauviae has no flagellate setae on head whereas S. chiricahua and S. reliquia have a pair at apicoscrobal position and a pair straddling the midline just anterior of the posterior margin of head. Strumigenys reliquia also has another pair about midlength of the upper scrobal margin and is the only western species with a fringe of simple fine and elongate setae on the anterior margin of clypeus. Otherwise, general head and clypeal pilosity is similar to western species S. arizonica , S. californica ( Brown, 1950) , and S. mendezi , but dentition differs. The diastema is absent or shorter than the length of the first basal tooth in S. arizonica , S. californica , and S. mendezi ; in S. moreauviae it is longer.

Description of worker. Mandible with five main teeth followed by two smaller teeth nearly as large as first tooth. These teeth are followed by two smaller denticles (these teeth are very difficult to see in closed mandible holotype) and ending with a slightly longer apical tooth. The first principle tooth is about half as long as second tooth. These first two teeth do not overlap in closed position; diastema is about equal or subequal to first tooth and longer than length of second tooth; teeth two through five alternating in length with teeth one through three progressively increasing in size. Of the first four teeth, only the third touches or overlaps, teeth one and four each with an obvious space between teeth when closed, denticles at apices are the only teeth to fully overlap. Eye with six pigmented ommatidia. Head in dorsolateral view flat without a noticeably higher vertex and only raised slightly at antennal insertion and posterior border of clypeus. Clypeus is 1.14 times wider than long and pentagonal in shape, having angular junctions on free margins where anterior and anterolateral margins meet. Anterior margin generally flat but having a slight concave impression between inner margins of mandibles (excluding basal mandibular process). Upper scrobal margin weakly marginate and ending at level of eye. Anterior of scape marginate, enlarged and flattened at sub-basal bend but not strongly angulate, subcylindrical in cross section, and with ventral glandular bulla of scape apparent as an elongate narrow oval patch located in apical third scape. In profile, dorsal surfaces of pronotum and mesonotum are flat and join at a broadly rounded angle. Propodeal tooth lamellate, triangular, and not well differentiated from subtended lamella of declivitous face.

Pilosity. No flagellate setae present on any surface of the body. Head with short spatulate setae that bend and point towards the midline of head and with 2–3 pairs of elongate simple and shallowly curved setae near the posterior vertex border beyond the vertex of head. Dorsum of clypeus with similar and slightly larger spatulate to spoonshaped setae directed toward the mandibles or toward the midline. Lateral and anterior border of the clypeus also fringed with short spatulate to spoon-shaped that are slightly larger than those on the clypeal dorsum; lateral fringe of setae are spoon-shaped and are directed anteriorly; anterior fringe of setae limited to two pair of spatulate setae that are smaller than lateral setae and are directed ventrally and slightly towards the midline of mandibles. Scape sparsely covered with short simple to shallowly expanded appressed setae; anterior margin with a row of differentiated spatulate setae with 2–3 spatulate setae curving toward the base of scape. Dorsum of mesosoma with four pair of suberect to shallowly curved elongate simple to slightly expanded setae; one pair at humeral angle; two pair on pronotal dorsum; and a smaller pair of curved simple setae at anterior edge of metanotal suture. Node of petiole and postpetiole with long simple setae that closely follow their surfaces. First gastral tergite with a row of four elongate simple setae arising near the margin of the limbus; first gastral sternite without standing pilosity; short appressed pubescence sparsely scattered on tergite and present only on lateral surfaces of tergite. No standing setae on legs.

Sculpture. Head and clypeus strongly punctate to reticulopunctate with lateral scrobal margins punctate. Dorsum of mesosoma without or with a weakly developed medial carina that is covered by reticulopunctate sculpture; flanked by weak irregular striae that are more strongly developed on dorsum of propodeum. Side of pronotum is reticulopunctate and having a large smooth and shining medial band without sculpture. Side of mesonotum and propodeum smooth and shining except for a small punctate sculpture present at the base of the mesopleurae; covering the bulla of the mesopleural gland and the small area between the propodeal spiracle and the lamella of the propodeum. Node of petiole heavily reticulopunctate. Exposed disc of postpetiole free of sculpture. Gaster smooth and shining without sculpture between and posterior basigastral costulae that extend about 1/3 of the first gastral tergite.

Spongiform appendages. Lateral lobe of petiole as long as length of petiolar node; ventral curtain as on postpetiole and present as a ventral curtain on the peduncle of petiole that is as deep as the base of the peduncle; disc of postpetiole encircled by a fringe of spongiform cuticle; ventral lobe of postpetiole deeper than exposed height of disc in lateral view; margin of lamella following the declivitous face of propodeum is irregular and projecting further than length of propodeal tooth in basal half above bulla of metapleural gland.

Taxonomic notes: The holotype is missing some body parts (the last funicular segment of the right antenna, the left foreleg beyond the trochanter, the right hind leg, and the left tarsal segments, and likely some pilosity). However, complementary body parts or setae are present to appear to represent a full description.

Etymology. Named after distinguished scientist and myrmecologist Dr. Corrie S. Moreau for her significant contributions as an evolutionary biologist. I met Dr. Moreau as a student at the first Ant Course in 2001 and was infected, as many other myrmecologists have been, by her viral enthusiasm of the ant world and unapologetic inclusiveness. The name was created by adding the singular Latin genitive case suffix -ae to the last name of a female person, this ending preceded by the infix -vi- inserted for ease of pronunciation. The orthography of an eponym is an unchangeable genitive noun and does not depend on the generic name in which the epithet is used.

Comments. Known only from the holotype worker collected by a student, E. R. Millard on a riparian island of the Rio Grande in late Spring.

Figures

FIGURE 41. Holotype worker of Strumigenys moreauviae [CAS: casent0799753]. Photographed by Michele Esposito (Ant- Web 2021).