Crematogaster marioni, BUREN, 1968

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 : 918

CREMATOGASTER MARIONI BUREN, 1968 , STAT. REV.

( FIG. 26 )

Crematogaster marioni Buren, 1968 b: 105 . Holotype worker, Morena Lake , San Diego Co., California (W. F. Buren) (LACM) (examined).

Junior synonym of C. emeryana: Morgan & Mackay, 2017: 171 ; here overturned.

Worker measurements (N = 18): HW 0.72–1.05, HL 0.71–0.98, SL 0.56–0.73, WL 0.81–1.14, MtFL 0.60– 0.82, MSC 4–15, A4SC 19–38, PP-SL/HW 0.08–0.14, CI 1.01–1.09, OI 0.24–0.28, SI 0.69–0.80, MtFL/HW 0.78–0.89, SPL/HW 0.16–0.23, SPTD/HW 0.43–0.56.

Discussion: Crematogaster emeryana and C. marioni exhibit notable differences in morphology, biology and distribution. They also have no close phylogenetic relationship to one another, with C. marioni being sister to C. coarctata , while C. emeryana appears to be a western offshoot of C. lineolata ( Fig. 1 ). The most noticeable distinctions between the two species are as follows:

• Scape length: shorter in C. marioni (SI 0.69–0.80, SL/HL 0.73–0.81, SL/WL 0.64–0.71; N = 18), longer in C. emeryana (SI 0.82–0.89, SL/HL 0.84–0.90, SL/ WL 0.74–0.79; N = 12) ( Fig. 46 ).

• Conspicuous striae on lower mesopleuron: usually present in C. marioni , absent in C. emeryana .

• Standing pilosity on gaster: common in C. marioni (A4SC 19–38), sparser in C. emeryana (A4SC 8–16).

• Nesting habits: arboreal ( C. marioni ) vs. grounddwelling ( C. emeryana ).

Distribution and biology: Crematogaster marioni is endemic to the California floristic province and occurs from northern California to northern Baja California. It has been recorded from a variety of low- to mediumelevation habitats, including oak woodland, riparian woodland, Quercus–Pinus–Pseudotsuga forest, pine forest/woodland, chaparral and coastal scrub. Nest site records include oak galls; dead branches of Arctostaphylos, Baccharis, Pinus and Quercus and rotten pine logs.

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 25–30. Crematogaster workers, showing lateral view of body (A), full-face view of head (B) and dorsal view of body (C). 25, C. opuntiae (CASENT0922738); 26, C. marioni (CASENT0922734); 27, C. coarctata (CASENT0005667); 28, C. hespera holotype (USNMENT00529501); 29, C. browni (CASENT0922722); 30, C. emeryana (CASENT0922729). Images courtesy of AntWeb (www.antweb.org); photographers Wade Lee (25, 26, 29, 30), April Nobile (27), Michele Esposito (28).

Figures 40–47. Bivariate plots of selected worker measurements in the Crematogaster scutellaris group. 40, PP-SL (postpetiole seta length) by HW (head width) in C. browni (N = 16) and C. cerasi (N = 17); 41, ED (eye diameter) by MtFL (metafemur length) in C. californica (N = 22) and C. coarctata (N = 21); 42, MtFL (metafemur length) by HW (head width) in C. californica (N = 22), C. colei (N = 12) and C. opuntiae (N = 10); 43, MtFL (metafemur length) by HW (head width) in C. depilis (N = 15), C. detecta (N = 11) and C. larreae (N = 5); 44, MtTL (metatibia length) by HW (head width) in C. depilis (N = 15), C. detecta (N = 11) and C. larreae (N = 5); 45, SPL (propodeal spine length) by HW (head width) in workers of C. hespera (N = 18), C. laeviuscula (N = 25) and C. parapilosa (N = 15); 46, SL (scape length) by HW (head width) in C. emeryana (N = 12) and C. marioni (N = 18); 47, SPTD (propodeal spine tip distance) by HW (head width) in C. lineolata (N = 26) and C. punctulata (N = 15).