Crematogaster parapilosa, Ward & Blaimer, 2022

Ward, Philip S. & Blaimer, Bonnie B., 2022, Taxonomy in the phylogenomic era: species boundaries and phylogenetic relationships among North American ants of the Crematogaster scutellaris group (Formicidae: Hymenoptera), Zoological Journal of the Linnean Society 194, pp. 893-937 : 919-922

CREMATOGASTER PARAPILOSA SP. NOV.

( FIG. 37 )

Zoobank registration: urn:lsid:zoobank.org:act:529E00DF-E3E5-4087-BA6E-0E9E037EFE6A .

Crematogaster atkinsoni ; Buren, 1968: 92 (nec Wheeler, 1919:108).

Crematogaster atkinsoni ; Johnson, 1988: 316 (nec Wheeler, 1919:108).

Crematogaster atkinsoni ; Deyrup 2017: 61 (nec Wheeler, 1919:108).

Crematogaster laeviuscula ; Morgan & Mackay, 2017: 197 (nec Mayr, 1870: 993) (in part).

Type material: Holotype worker, US, Florida, Sarasota Co.: Longino Ranch , 10 m, 27.15564 −82.11670 ± 3 m, 1 October 2016, P. S. Ward PSW17790, on low vegetation, Cephalanthus swamp (CASENT0863386) ( USNM) . Paratypes: ten workers, same data as holotype (CASENT0842343, CASENT0863137, CASENT 0863387, CASENT 0863388 CASENT 0863389, CASENT 0863390 CASENT0863391, CASENT0863392) (CASC, FSCA, LACM, MCZC, UCDC) .

Non-type material: US, Alabama, Baldwin Co.: Bon Secour River, 16 km SW Foley (D. E. Read) (CASC); US, Florida, Collier Co.: Big Cypress Natl. Preserve, Concho Billy Trail (D. M. Olson) ( UCDC); Collier Co.: Collier-Seminole State Park (P. S. Ward) ( UCDC); Leon Co.: Tall Timbers Plant. (B. V. Travers) ( LACM); Monroe Co.: Big Pine Key (T. Daccy) ( NCSU); Palm Beach Co.: West Palm Beach (W. F. Buren) ( LACM); Sarasota Co.: Albee Farm & Laurel Rd. (W. Rodriguez- Cayro) ( UCDC); Sarasota Co.: Myakka River St. Pk. (J. Longino) (CASC).

Worker measurements (N = 15): HW 0.83–1.13, HL 0.78–1.01, SL 0.67–0.85, WL 0.93–1.22, MtFL 0.74– 0.95, MSC 0–8, A4SC 11–24, PP-SL /HW 0.14–0.20, CI 1.04–1.12, OI 0.23–0.25, SI 0.76–0.87, MtFL /HW 0.84– 0.92, SPL/HW 0.26–0.34, SPTD/HW 0.56–0.71.

Worker diagnosis: Head broader than long, with convex sides, posterior margin straight to weakly concave; scapes moderately long, surpassing the posterior margin of head by distal scape width or more (SI 0.76–0.87, SL/HL 0.84–0.91, SL/WL 0.70–0.79); eye of moderate size (OI 0.23–0.25, ED/HL 0.24–0.27, ED/ MtFL 0.25–0.29); pronotal humeri weakly developed; anteromedial mesonotal carina prominent in profile; dorsal face of mesonotum flat, then rounding gently into mesonotal declivity; propodeal spines long and slender ( SPL /HW 0.26–0.34, usually> 0.27, SPL / WL 0.23–0.31), strongly divergent ( SPTD / HW 0.56–0.71); petiole subtrapezoidal, with moderate lateral expansion ( PTW / HW 0.35–0.41); postpetiole broad ( PPW / HW 0.31–0.35), with prominent median furrow; legs of moderate length ( MtFL /HW 0.84–0.92, MtFL /HL 0.92–1.00). Mandibles striate; head and mesosoma dorsum predominantly smooth and shiny, excepting usual anterolateral striae on head and weak reticulate to reticulate-striate sculpture on promesonotum, mostly laterally and on mesonotal declivity; mesopleuron reticulate-foveolate, opaque, overlain by rugulae on upper-third; petiole, postpetiole and gaster smooth and shining, with weak reticulation on postpetiole and side of petiole. Standing pilosity moderately developed, present as two to six hairs in a row on each side of the midline of the front of the head, as none to four hairs on each pronotal humerus ( MSC 0–8), as paired setae on the petiole and postpetiole ( PP-SL / PPW 0.38–0.54), and as scattered setae on the first gastric (fourth abdominal) tergite (A4SC 11–24). Pubescence present on most of body, appressed or decumbent and generally distinct from the standing pilosity (i.e. not becoming suberect). Medium to dark brown (workers in some populations bicoloured to reddish brown).

Comments: This is a marsh-inhabiting species of the south-eastern United States that has been masquerading under the name of a different species, Crematogaster atkinsoni (here considered a junior synonym of C. pilosa – see below). It has been recognized for some time that workers of C. parapilosa , going by the name ‘ C. atkinsoni ’, can be distinguished from those of the closely related species, C. pilosa , by their lesser amount of standing pilosity and more consistently appressed pubescence, especially on the head ( Johnson, 1988; Deyrup, 2017). A lateral or posterodorsal view of the head is the best way to appreciate this difference: in C. parapilosa there are two to six pairs of long, standing hairs flanking the midline of the head, and these stand apart from the shorter appressed and decumbent pubescence, whereas in C. pilosa the pubescence tends to be uplifted (suberect or subdecumbent), contrasting less with the longer paired setae, and imparting a hairier appearance to the head (see Johnson, 1988; Fig. 6 ). Examination of the type workers of C. atkinsoni reveals that they have the pilosity characteristics of C. pilosa , and a new name is therefore required for the less pilose species. The two species are broadly sympatric in much of Florida ( Deyrup, 2017) and they apparently co-occur – or previously co-occurred – at the type locality of C. atkinsoni (Fort Myers, Florida). Wheeler (1919) described the biology of what is probably C. parapilosa – in particular, the carton nest construction – yet the workers that were designated type specimens appear to be C. pilosa .

Morgan & Mackay (2017: 197) considered C. parapilosa (as ‘ C. atkinsoni ’) to be a junior synonym of C. laeviuscula , a midwestern species that nests in dead stems, branches and logs, and occurs from Kansas and Missouri south to Texas and north-eastern Mexico ( Creighton, 1950; Buren, 1968; Johnson, 1988). Apart from biological and distributional differences, all but the smallest workers of C. parapilosa can be distinguished from those of C. laeviuscula by their disporportionately longer propodeal spines ( Fig. 45 ) (for worker HW> 0.85 mm, SPL/HW 0.29–0.34 in C. parapilosa vs. 0.21–0.27 in C. laeviuscula ). Our phylogenomic (UCE) data indicate that C. parapilosa is sister to C. laeviuscula + C. pilosa ( Fig. 1 ).

Distribution and biology: Crematogaster parapilosa is an arboreal species found in marsh habitats of the south-eastern United States. We have examined material from Florida and Alabama, and there are also records (as ‘ C. atkinsoni ’) from as far north as North Carolina ( Guénard et al., 2012). This species typically constructs carton nests on vegetation ( Wheeler, 1919; Deyrup, 2017), but Johnson (1988: 317) reported variation in this behaviour, with some nests being found in plant cavities without the use of carton. The apparent biological and morphological differences between C. parapilosa and C. pilosa , and the extent of intraspecific variation in both taxa, need further study.

Etymology. The name ‘ parapilosa ’ alludes to the close relationship of this species to C. pilosa , using the Greek preposition παρα -, meaning near or beside.

Figures

Figure 1. Phylogeny of the North American Crematogaster scutellaris group. Maximum likelihood phylogenetic tree estimated from the 90% taxon completeness matrix after application of spruceup trimming with a 0.98 cut-off (90%-0.98-spruceup), using a combined best tree and ultrafast bootstrap (N = 1000) search in IQ-TREE v.1.6.12 and implementing 746 partitions. The analysis was rooted using the most distantly related outgroup taxon C. cf.rogenhoferi; the long branch leading to this taxon has been shortened for space-saving purposes. All nodes have bootstrap support = 100% unless labelled otherwise. Species images courtesy of AntWeb (www.antweb.org).

Figures 37–39. Crematogaster workers, showing lateral view of body (A), full-face view of head (B), and dorsal view of body (C). 37, C.parapilosa holotype (CASENT0863386); 38, C. laeviuscula (CASENT0104828); 39, C.lineolata (CASENT0922733). Images courtesy of AntWeb (www.antweb.org); photographers Zachary Griebenow (37), April Nobile (338), Wade Lee (39).

Figures 3–12. Crematogaster worker features useful for identification. 3, petiole shape, dorsal view, C. lineolata (CASENT0863235) (3A) and C. torosa (CASENT0795540) (3B); 4, sculpture on declivitous face of propodeum, C. dentinodis (CASENT0863070) (4A) and C. depilis (CASENT0863478) (4B); 5, mesosomal pilosity, C. punctulata (CASENT0863277) (5A) and C.emeryana (CASENT0863099) (5B); 6, position and shape of propodeal spines, dorsal view, C.isolata (CASENT0863072) (6A) and C.pinicola (CASENT0882129) (6B); 7, petiole shape, dorsal view, C.mutans (CASENT0862488); 8, subpetiolar tooth, lateral view, C.mutans (CASENT0862488); 9, promesonotal sculpture, C.californica (CASENT0221085)(9A) and C.coarctata (CASENT0221962) (9B); 10, postpetiolar seta, C. browni (CASENT0863144) (10A) and C. cerasi (CASENT0795541) (10B); 11, cephalic pilosity, C. torosa (CASENT0795540) (11A) and C. missouriensis (CASENT0221041) (11B); 12, mesosomal profile, C. crinosa (CASENT0795543) (12A) and C. torosa (CASENT0863226) (12B).