Crematogaster
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publication ID |
https://doi.org/ 10.1093/zoolinnean/zlab047 |
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publication LSID |
lsid:zoobank.org:pub:6144DD31-0F7B-4589-86A3-F40994452C9 |
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persistent identifier |
https://treatment.plazi.org/id/039987E6-FFF6-FFDE-FF0A-7F55FECD6108 |
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treatment provided by |
Plazi |
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scientific name |
Crematogaster |
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Following Buren (1968), the nominate subgenus of Crematogaster View in CoL , represented in the Nearctic region by the Crematogaster scutellaris group, is divided by geography into those species occurring in eastern and western North America, here defined arbitrarily as east and west of 102°W longitude. Only two species ( C. cerasi and C. punctulata ) occur in both regions. The last portion of the key (couplets 31–35) covers the six species of Crematogaster (Orthocrema) occurring in the United States and is based on Longino (2003) and Shattuck & Cover (2016). Two other Neotropical species of the subgenus Orthocrema , C. sotobosque Longino, 2003 and C. curvispinosa Mayr, 1862, have been reported from the United States ( Morgan & Mackay, 2017), but we do not consider these records credible.
1. Petiole as wide as, or wider than, long and broadened anteriorly ( Fig. 3A View Figures 3–12 ); postpetiole bilobed, wider than long and with distinct median sulcus; Crematogaster (Crematogaster) .........................................................2
- Petiole rectangular or ovorectangular, longer than wide and not widened anteriorly ( Fig. 3B View Figures 3–12 ); postpetiole subglobular and lacking a distinct median sulcus, except in one species (C. corvina); Crematogaster (Orthocrema) ....................................................................................................................................................31
2. Species occurring in the western United States, west of 102°W .................................................................... 3
- Species occurring east of 102°W in the United States and Canada.............................................................22
3. Mesosoma dorsum densely reticulate-foveolate and opaque, with some overlying rugulae in larger workers; declivitous face of propodeum completely covered with reticulate-foveolate sculpture ( Fig. 4A View Figures 3–12 ); seta-bearing posterolateral extremity of petiole in form of small acute tooth; standing pilosity short and stout, relatively sparse on mesosoma (MSC 4–12), but abundant on gaster (A4SC 48–80) ( Fig. 13A View Figures13–18 ); relatively small species (HW 0.73–1.02), with broad petiole ( PTW /HW 0.37–0.41) ( Fig. 13C View Figures13–18 ); Arizona, New Mexico and Mexico........................................................................................................................................................ C. dentinodis
- Mesosoma sculpture variable, but declivitous face of propodeum usually weakly reticulate and sublucid, or smooth and shining ( Fig. 4B View Figures 3–12 ); seta-bearing posterolateral extremity of petiole usually blunter and not in the form of a small acute tooth; standing pilosity almost never in the combination of sparse on the mesosoma and abundant on the gaster, but if this condition applies (see couplet 4 below) then larger, on average (HW 0.96–1.27), with narrow petiole ( PTW /HW 0.32–0.34) ............................................................. 4
4. Mesosoma predominantly reticulate-foveolate and opaque, with overlying rugulae ( Fig. 14C View Figures13–18 ); promesonotum with short, standing hairs that grade into, and are sometimes difficult to distinguish from, uplifted pubescence (MSC 6–24); gaster with abundant, short, standing pilosity (A4SC 38–70) ( Fig. 14A View Figures13–18 ); larger species (HW 0.96–1.27) with moderately long scapes (SI 0.74–0.83, SL/HL 0.82–0.92) and propodeal spines (SPL/HW 0.20–0.23) and narrow postpetiole ( PPW /HW 0.27–0.30) ( Fig. 14C View Figures13–18 ); southern Arizona, Sonora .............................................................................................................................................................. C. vetusta
- Sculpture and pilosity variable but not in the above combination; if standing pilosity abundant on gaster (A4SC> 35) then species smaller, on average (HW 0.71–1.10), and either with more conspicuous mesosomal pilosity (MSC 16–30) and broader postpetiole ( PPW /HW 0.29–0.35) (C. navajoa, C. punctulata ) or mesosoma with reticulate-striate sculpture and scapes shorter (SL/HL 0.73–0.81) ( C. marioni )............ 5
5. Standing pilosity abundant, present on most of the dorsal surface of the mesosoma and gaster (MSC 16–30, A4SC 20–55) ( Figs 5A View Figures 3–12 , 15A View Figures13–18 ); scape and legs of moderate length relative to mesosoma length (SL/ WL 0.69–0.82, MtFL /WL 0.77–0.85) ................................................................................................................6
- Standing pilosity varying from sparse to common, but not present on the entire dorsal surface of the mesosoma and gaster (MSC 0–15, A4SC 0–38), if present on mesosoma dorsum then usually confined to the pronotal humeri and the mesonotal declivity ( Fig. 5B View Figures 3–12 ); rarely (some workers of C. marioni ) one or two standing hairs on middle of promesonotum but in that case scape and legs short relative to mesosoma length (SL/WL 0.64–0.69, MtFL /WL 0.72–0.76) ..............................................................................................7
20. Upper-third of head predominantly smooth and shiny, with relatively coarse punctures (> 0.01 mm diameter); standing pilosity long and abundant, especially on the gaster (A4SC 14–30) ( Fig. 29A View Figures 25–30 ); longest postpetiolar seta about two-thirds of postpetiole width ( PP-SL / PPW 0.59–0.75) ( Fig. 10A View Figures 3–12 ; see also Fig. 40 View Figures 40–47 ); west Texas, New Mexico, Arizona and adjacent Mexico........................................................... C. browni - Upper-third of head with smaller punctures (<0.01 mm diameter) and often with greater incursion of finely reticulate surface sculpture; standing pilosity shorter and less abundant on gaster (A4SC 4–16) ( Fig. 30A View Figures 25–30 ); longest postpetiolar seta about one-half of postpetiole width or less ( PP-SL / PPW 0.38–0.54) ( Fig. 10B View Figures 3–12 ).....21
21. Standing pilosity present on pronotal humeri and on mesonotal declivity (MSC 6–13) ( Figs 5B View Figures 3–12 , 30A View Figures 25–30 ); scape relatively long (SI 0.82–0.89); propodeal spines short (SPL/HW 0.18–0.22); Colorado and Utah to northern Mexico........................................................................................................................... C. emeryana - Standing pilosity on mesosoma restricted to pronotal humeri (MSC 2–7) ( Fig. 31A View Figures 31–36 ); scapes shorter (SI 0.72–0.81); propodeal spines longer (SPL/HW 0.22–0.25); eastern Canada, south to Florida and west to the Great Plains and Rocky Mountain foothills................................................................................ C. cerasi
22. Promesonotum with distinct rugulose sculpture, imparting a vermiculate (worm-like) appearance ( Fig. 32C View Figures 31–36 ); small species (HW 0.67–0.85), with short scapes and legs (SI 0.72–0.78, MtFL /HW 0.79–0.84) ( Fig. 32B View Figures 31–36 ); propodeal spines short and stout (SPL/WL 0.15–0.19), inwardly curved and directed posterad (SPTD/HW 0.39–0.48) ( Figs 32A, 32C View Figures 31–36 ); swamp-inhabiting species from south-eastern United States.................................................................................................................................................... C. vermiculata - Promesonotum lacking distinct rugulose-vermiculate sculpture; other characters variable ...................23
23. Pronotum with smooth or weakly sculptured median impression, flanked on each side by ruguloreticulate sculpture; in anterior view median impression of pronotum enhancing the distinctness of the median carina of the mesonotum (likened to a gun sight); small, dark-coloured arboreal species (HW 0.88–1.06) with conspicuous standing pilosity on mesosoma and gaster (MSC 12–17, A4SC 20–40) ( Fig. 33A, C View Figures 31–36 ); south-eastern Texas, north-eastern Mexico..................................................................................... C. rifelna - Pronotum without a smooth median depression, flanked by ruguloreticulate sculpture; size, pilosity and nesting habits variable .................................................................................................................................24
24. Propodeal spines short and distinctly incurved (SPL/HW 0.14–0.18; SPTD/HW 0.39–0.47) ( Fig. 6B View Figures 3–12 ); mesosoma smooth to weakly foveolate; standing pilosity relatively sparse on mesosoma and gaster (MSC 2–6, A4SC 5–13); small, arboreal species (HW 0.74–0.92)..........................................................................25 - Either propodeal spines longer and less incurved, or mesosoma more densely sculptured; standing pilosity and size variable..............................................................................................................................26
25. Uniformly dark brown (fresh specimens) ( Fig. 34 View Figures 31–36 ); arboreal species, with variable nesting habits, southeastern United States.................................................................................................................. C. ashmeadi - Bicoloured, gaster black and other body parts ferrugineus-red ( Fig. 35 View Figures 31–36 ); nesting in pine branches and under pine bark in open habitats; Florida and adjacent states ................................................... C. pinicola
26. Standing pilosity conspicuous on head ( Fig. 36B View Figures 31–36 ), with numerous short subdecumbent and suberect hairs (uplifted pubescence), in addition to several pairs of longer setae flanking the midline; standing pilosity also present as numerous fine hairs of varying degrees of inclination and length on mesosoma and gaster (MSC 10–30, A4SC 20–60) ( Fig. 36A View Figures 31–36 ); propodeal spines long (SPL/HW 0.22–0.29) ( Fig. 36C View Figures 31–36 ); south-eastern United States............................................................................................................... C. pilosa - Standing pilosity generally less common and more distinct from the appressed pubescence (at least on the mesosoma and gaster), or present as short bristle-like hairs; propodeal spine length variable........27
27. Propodeal spines long and divergent (SPL/HW 0.26–0.34, usually> 0.27) ( Fig. 37A, C View Figures 37–39 ); dorsal face of propodeum smooth or weakly sculptured; standing pilosity sparse (MSC 0–8, A4SC 11–24) ( Fig. 37A View Figures 37–39 ); marsh-inhabiting species from south-eastern United States, often building carton nests..... C. parapilosa - Propodeal spines shorter (SPL/HW 0.19–0.27); dorsal face of propodeum usually distinctly sculptured; standing pilosity variable; carton nests rarely or never constructed.........................................................28
28. Standing pilosity relatively sparse on mesosoma dorsum, confined to a clump of flexuous setae on the pronotal humeri and occasionally one or two setae on the mesonotal declivity, always lacking on propodeum (MSC 2–14) ( Figs 31A View Figures 31–36 , 38A View Figures 37–39 )......................................................................................................29 - Standing pilosity common and well distributed across the mesosoma dorsum, often including the propodeum (MSC 15–28) ( Figs 5A View Figures 3–12 , 39A View Figures 37–39 ) .....................................................................................................30
29. Side of pronotum and dorsum of promesonotum smooth and shining ( Fig. 38A, C View Figures 37–39 ); midwestern species, occurring from Kansas and Missouri to north-eastern Mexico C. laeviuscula
- Side of pronotum usually distinctly foveolate-striate, dorsum of mesosoma striate ( Fig. 31A, C View Figures 31–36 ); widely distributed, from eastern Canada, south to Florida and west to the Great Plains and Rocky Mountain foothills................................................................................................................................................ C. cerasi
30. Mesosoma dorsum reticulate-foveolate and opaque, lacking striae or rugulae ( Fig. 16C View Figures13–18 ); propodeal spines directed posteriorly, such that SPTD/HW 0.39–0.46 and SPTD/ PPW 1.11–1.36 ( Fig. 47 View Figures 40–47 ); Great Plains south to northern Mexico, west to Arizona; see remarks under ‘Species accounts’ ................. C. punctulata - Mesosoma dorsum usually with longitudinal rugulae or striae, on a weak reticulate or reticulate-foveolate sublucid background ( Fig. 39C View Figures 37–39 ); propodeal spines directed more posterolaterally such that SPTD/HW 0.46–0.63 and SPTD/ PPW 1.38–1.76 ( Fig. 47 View Figures 40–47 ); eastern Canada to southern United States and west to the Great Plains ................................................................................................................................... C. lineolata
31. Dorsum of head with dilute appressed pubescence and six or fewer standing hairs ( Fig. 11A View Figures 3–12 ................ 32 - Dorsum of head with abundant standing pilosity and no underlying short, appressed pubescence ( Fig. 11B View Figures 3–12 ) ......................................................................................................................................................34
32. Postpetiole bilobed, much wider than long and with a distinct median sulcus; head reticulate-foveolate and opaque ..................................................................................... C. corvina (southern Texas to Honduras) - Postpetiole globular to subquadrate, slightly broader than long, and lacking a distinct median sulcus; head less densely sculptured, mostly smooth and shiny, at least medially ............................................... 33
33. In profile promesonotum usually broadly convex ( Fig. 12A View Figures 3–12 ); anteroventral petiolar tooth relatively well- developed and sharp; gaster with abundant, evenly distributed standing pilosity; southern Texas to Argentina........................................................................................................................................... C. crinosa - In profile promesonotum tending to be somewhat flattened ( Fig. 12B View Figures 3–12 ); anteroventral petiolar tooth usually less well-developed, forming a right or weakly acute angle; standing pilosity moderately common on gaster, denser anterolaterally and often leaving a median strip relatively clear of setae; southern United States to South America ........................................................................................................ C. torosa
34. Standing pilosity on head short and bluntly clavate; body dark brown; Florida and Texas, south to Venezuela....................................................................................................................................... C. obscurata - Standing pilosity on head long and flexuous; body yellow to orange-brown, sometimes with darker head 35
35. Queen small (4–4.8 mm long); worker with short propodeal spines (SPL/HW 0.10–0.19); promesonotum with scattered longitudinal carinulae; mesopleuron predominantly smooth and shiny; eastern United States, west to Texas, south to Costa Rica.............................................................................. C. minutissima - Queen larger (5–6 mm long); where sympatric with C. minutissima in eastern United States, worker with longer propodeal spines (SPL/HW 0.20–0.24), promesonotum tending to have fewer carinulae, mostly on sides, and mesopleuron often reticulate-foveolate and opaque (in allopatry these worker differences do not apply; further study required); eastern United States, west to Utah, Arizona and northern Mexico................................................................................................................................................ C. missouriensis
SPECIES ACCOUNTS
In this section we discuss species for which taxonomic clarification is required, mostly those that were synonymized in Morgan & Mackay (2017) but that are here reinstated. We document differences between these species and their closest relatives and the species with which they were synonymized (usually not the same thing), using quantitative criteria whenever possible. We also discuss a few other taxa, and describe three new species. A full treatment of all species is beyond the scope of this paper, but current understanding of the remaining North American species is captured in the preceding worker-based key.
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