Taxonomy of the Crematogaster degeeri-species-assemblage in the Malagasy region (Hymenoptera: Formicidae)

We revise the species-level taxonomy of the Crematogaster (Crematogaster) degeerispecies-assemblage, a group of related ants occuring in Madagascar and the wider Malagasy region, and further provide an identification key to all species-groups of the genus Crematogaster in this region. Within the C. degeeri-assemblage, we recognize twelve species based upon morphological data from worker, queen and male ants, as well as genetic data from the barcode region of cytochrome oxidase I. Seven new species are described: Crematogaster alafara Blaimer sp. nov., C. bara Blaimer sp. nov., C. mafybe Blaimer sp. nov., C.maina Blaimer sp. nov., C. malahelo Blaimer sp. nov., C. masokely Blaimer sp. nov., C. ramamy Blaimer sp. nov. Crematogaster tricolor Gerstäcker, 1859 (stat. rev.) and C. dentata Dalla Torre, 1893 (stat. nov.) are raised to species level, and the following new synonymies are proposed: Crematogaster degeeri lunaris Santschi, 1928 as a synonym of C. degeeri Forel, 1886; Crematogaster sewelli improba Forel, 1907 and C. sewelli mauritiana Forel, 1907 as synonyms of C. dentata Dalla Torre, 1893, and C. pacifi ca Santschi, 1919 as a synonym of C. lobata Emery, 1895. Species descriptions, images, and distribution maps and identification keys based on worker ants, as well as on queen ants where available, are presented for all twelve species. In addition, we present a molecular gene tree for cytochrome oxidase I and summarize levels of sequence divergence within and between species of the C. degeeri-species-assemblage. Our findings are discussed in the light of previous work on Malagasy Crematogaster ants

The Chalcidoidea bush of life: evolutionary history of a massive radiation of minute wasps.

Chalcidoidea are mostly parasitoid wasps that include as many as 500 000 estimated species. Capturing phylogenetic signal from such a massive radiation can be daunting. Chalcidoidea is an excellent example of a hyperdiverse group that has remained recalcitrant to phylogenetic resolution. We combined 1007 exons obtained with Anchored Hybrid Enrichment with 1048 ultra-conserved elements (UCEs) for 433 taxa including all extant families, >95% of all subfamilies, and 356 genera chosen to represent the vast diversity of the superfamily. Going back and forth between the molecular results and our collective knowledge of morphology and biology, we detected bias in the analyses that was driven by the saturation of nucleotide data. Our final results are based on a concatenated analysis of the least saturated exons and UCE datasets (2054 loci, 284 106 sites). Our analyses support an expected sister relationship with Mymarommatoidea. Seven previously recognized families were not monophyletic, so support for a new classification is discussed. Natural history in some cases would appear to be more informative than morphology, as illustrated by the elucidation of a clade of plant gall associates and a clade of taxa with planidial first-instar larvae. The phylogeny suggests a transition from smaller soft-bodied wasps to larger and more heavily sclerotized wasps, with egg parasitism as potentially ancestral for the entire superfamily. Deep divergences in Chalcidoidea coincide with an increase in insect families in the fossil record, and an early shift to phytophagy corresponds with the beginning of the "Angiosperm Terrestrial Revolution". Our dating analyses suggest a middle Jurassic origin of 174 Ma (167.3-180.5 Ma) and a crown age of 162.2 Ma (153.9-169.8 Ma) for Chalcidoidea. During the Cretaceous, Chalcidoidea may have undergone a rapid radiation in southern Gondwana with subsequent dispersals to the Northern Hemisphere. This scenario is discussed with regard to knowledge about the host taxa of chalcid wasps, their fossil record and Earth's palaeogeographic history

Orthocrema

Key to the subgenera <i>Orthocrema</i> and <i>Crematogaster</i> <p>1 Postpetiole globular, lacking median impression (Figs 7, 24), or merely impressed posteriorly (Figs 8, 21 b, 25)........... 2</p> <p>– Postpetiole bilobed, with a broad or sharp, more or less distinct median impression (Figs 9, 14 b–19b, 22b, 23)............ 4</p> <p> 2(1) Petiole rectangular or ovo-rectangular (Figs 3 and 4); dorsoposterior setae and/or denticles usually present on petiole; propo- deal spiracle circular or subcircular (Fig. 11); <i>global</i>.................................................. <i>Orthocrema</i></p> <p>– Petiole of different form (Figs 5, 14 a–19a, 20, 21a–22a); dorsoposterior setae and denticles present or absent; propodeal spira- cle variable.......................................................................................... 3</p> <p> 3(2) Petiole elongate rectangular (Fig. 5); propodeal spiracle circular or subcircular (Fig. 11); <i>global.............. Orthocrema</i></p> <p> – Petiole of variable form (Figs 14 a–19a, 20, 21a–22a), <b>if</b> elongate rectangular (Fig. 20), <b>then</b> propodeal spiracle compressed oval (Fig. 26); <i>Old World</i>.................................................................... <i>Crematogaster</i></p> <p> 4(1) Petiole rectangular or ovo-rectangular (Figs 3 and 4); dorsoposterior setae and/or denticles usually present on petiole; <i>Neotro- pical and Malagasy region</i>...................................................................... <i>Orthocrema</i></p> <p> – Petiole of different form (Figs 14 a–19a, 20, 21a–22a); dorsoposterior setae and denticles present or absent; <i>global</i>................................................................................................... <i>Crematogaster</i></p>Published as part of <i>Blaimer, Bonnie B., 2012, A subgeneric revision of Crematogaster and discussion of regional species-groups (Hymenoptera: Formicidae), pp. 47-67 in Zootaxa 3482</i> on page 54, DOI: <a href="http://zenodo.org/record/209409">10.5281/zenodo.209409</a&gt

Crematogaster sisa Blaimer, 2010, NEW SPECIES

<i>Crematogaster sisa</i> NEW SPECIES <p>(Fig. 33 & 39)</p> <p> <b>Holotype worker.</b> MADAGASCAR: R.S. Manongarivo, -14.02167, 48.41833, 1580m, 27.x.1998, sifted litter (leaf mold, rotten wood), montane rainforest, B.L.Fisher#1970(49)-2 (CASENT0193556, specimen image on antweb) (deposited in CASC).</p> <p> <b>Paratypes.</b> 4w, same locality and collection data as holotype (B.L.Fisher#1970(49)-2, CASENT0193557, CASENT0193542 and CASENT0193543; #1972(11)-1, CASENT0193009) (deposited in MCZC, SAMC, MHNG, UCDC).</p> <p> <b>Material examined.</b> (CASC) MADAGASCAR: <i>Antsiranana</i>: R.S. Manongarivo: -14.02167, 48.41833, 1580m; -14.04667, 48.40167, 1860m (B.L.Fisher).</p> <p> <b>Worker measurements</b> (n=10). HW 0.89–1.14; HL 0.81–1.08; EL 0.21–0.27; SL 0.73–0.84; WL 0.91– 1.12; SPL 0.16–0.24; PTH 0.16–0.23; PTL 0.24–0.31; PTW 0.26–0.35; PPL 0.17–0.22; PPW 0.24–0.33; LHT 0.71–0.90; CI 1.05–1.17; OI 0.22–0.28; SI 0.78–0.90; SPI 0.17–0.21; PTHI 0.65–0.83; PTWI 0.91–1.24; PPI 1.33–1.53; LBI 1.23–1.30.</p> <p> <b>Worker description.</b> Medium to large species (HW 0.89–1.14, WL 0.91–1.12).</p> <p>Masticatory margin of mandibles with 5 teeth; posterior margin of head straight or medially depressed, laterally forming gentle round corners; 1–3 ocelli sometimes present on large workers; antennal scapes just surpassing posterior margin of head; midline of eyes situated at midline of head in full face view.</p> <p>Pronotum laterally angular; promesonotal suture usually complete, and distinctly and broadly impressed, continuing laterally to mesopleural spiracle and thereby constricting mesonotum in relation to pronotum; dorsum of promesonotum more or less flat in lateral view; antero-medial portion of mesonotum slightly raised with respect to pronotum, but not tuberculate; dorsum of mesonotum flat, lateral portion broadly angular; mesonotum postero-laterally angular or tuberculate, and with a distinct to indistinct posterior face; propodeal spines small to medium sized (SPI 0.17–0.21), half as long to as long as width between their bases, evenly tapering, straight or weakly down-curved, in dorsal view weakly diverging; petiole in dorsal view trapezoidal or suboval, weakly lobed or rounded, laterally weakly carinate, with weak postero-lateral tubercle; dorsum of petiole weakly concave; subpetiolar process articulated as acute and distinct antero-ventral tooth, but rarely may be present as only a minute tooth.</p> <p>Head sculpture aciculate; mesosoma with mesopleuron costulate, and metapleuron partly costulate, partly aciculate; dorsal face of propodeum weakly carinulate; posterior face largely shiny; otherwise mesosoma largely aciculate; dorsal face of petiole mostly shiny; lateral and ventral face of petiole coarsely reticulate; postpetiole dorsally and ventrally rugulose; helcium carinulate; face usually with 4-6 erect setae; promesonotum with 0-2 erect humeral setae; petiole and postpetiole lacking erect pilosity.</p> <p>Colour brown to dark brown.</p> <p> <b>Variation.</b> There seems to be considerable gradual size variation in workers, but sampling of this species is too sparse to give a general statement.</p> <p> <b>Comments.</b> This species is easily distinguished morphologically by its uniquely shaped subpetiolar process in form of an acute tooth. The species status of <i>C. sisa</i> is further well supported by both mitochondrial and nuclear DNA sequences.</p> <p> <b>Distribution and biology.</b> <i>Crematogaster sisa</i> has to be regarded as a high-elevation endemic, known to date only from two localities in the rugged and isolated Manongarivo massif (<b>Fig. 59</b>) that were visited during a biological inventory in 1998 by B.L. Fisher (see Fisher, 2002). Collections of foraging workers were made while sifting litter and beating vegetation in montane rainforest habitats at 1580 and 1860 m. No nest collections have yet been recorded for this species, thus reproductives and natural history are entirely unknown. The Manongarivo massif lies in the Sambirano Region of Madagascar’s northwest and is part of a mountain complex spanning much of northern Madagascar (Gautier & Goodman, 2002) – probably one of the least accessible and least studied regions of the island. Further inventory efforts in this region may therefore result in expanding the known distribution of <i>C. sisa</i> and lead to the discovery of colonies and their nesting habits. The species occurs in sympatry with the <i>C. hova</i> -complex, but appears to be parapatric in distribution to <i>C. nosibeensis</i> by virtue of elevation, since the latter is found in northwest Madagascar only in lowland forests.</p> <p> <b>Etymology.</b> “ Sisa ” is Malagasy for “remnant” and this species is named in allusion to its isolated distribution. “ Sisa ” is used in this combination as a noun in apposition.</p>Published as part of <i>Blaimer, Bonnie B., 2010, Taxonomy and Natural History of the Crematogaster (Decacrema) - group (Hymenoptera: Formicidae) in Madagascar, pp. 1-39 in Zootaxa 2714</i> on pages 29-37, DOI: <a href="http://zenodo.org/record/199681">10.5281/zenodo.199681</a&gt

Crematogaster browni Buren 1968

CREMATOGASTER BROWNI BUREN, 1968, STAT. REV. (FIGS 10A, 29)Published as part of 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), pp. 893-937 in Zoological Journal of the Linnean Society 194 on page 907, DOI: 10.1093/zoolinnean/zlab04

Figures 31–36 in Taxonomy in the phylogenomic era: species boundaries and phylogenetic relationships among North American ants of the Crematogaster scutellaris group (Formicidae: Hymenoptera)

Figures 31–36. Crematogaster workers, showing lateral view of body (A), full-face view of head (B) and dorsal view of body (C). 31, C. cerasi lectotype (USNMENT00529078); 32, C. vermiculata (CASENT0914534); 33, C. rifelna holotype (LACMENT164556); 34, C. ashmeadi (CASENT0922720); 35, C. pinicola (CASENT0172943); 36, C. pilosa (CASENT0914530). Images courtesy of AntWeb (www.antweb.org); photographers Michele Esposito (31, 33), Zach (Ziv) Lieberman (32, 36), Wade Lee (34), April Nobile (35).Published as part of <i>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), pp. 893-937 in Zoological Journal of the Linnean Society 194</i> on page 921, DOI: 10.1093/zoolinnean/zlab047, <a href="http://zenodo.org/record/10115063">http://zenodo.org/record/10115063</a&gt

Crematogaster larreae Buren 1968

CREMATOGASTER LARREAE BUREN, 1968, STAT. REV. (FIG. 22) Crematogaster larreae Buren, 1968: 117. Holotype male, Franklin Mts., El Paso, Texas (W. F. Buren) (LACM) (examined). Junior synonym of C. depilis: Morgan & Mackay, 2017: 155; here overturned. Worker measurements ( N = 5): HW 0.74–1.05, HL 0.71– 0.99, SL 0.59–0.78, WL 0.80–1.09, MtFL 0.63–0.87, MSC 0, A4SC 0, PP-SL/HW 0.10–0.13, CI 1.00–1.06, OI 0.27–0.31, SI 0.74–0.80, MtFL/HW 0.83–0.85, SPL/ HW 0.19–0.23, SPTD/HW 0.48–0.53. Discussion: Crematogaster larreae was described by Buren (1968) as a ‘cryptic’ species closely related to and sympatric with C. depilis, having distinctive queens and males but workers that are very similar to those of C. depilis. The primary difference between the workers of the two species is their colour: C. larreae workers have the head and mesosoma dark brown and the gaster brownish-black, while in C. depilis the head and mesosoma vary from yellowish-brown to reddishbrown (the head may be darker than the mesosoma), and the gaster is medium to dark brown. However, this distinction is tenous and difficult to ascertain in older, faded specimens. Buren (1968) also provided evidence of differences in biology, with C. larreae apparently confined to nesting at the base of creosote bush (Larrea tridentata), in contrast to the generalized ground-nesting habits of C. depilis. Because they could not distinguish the workers of these two forms, Mackay & Morgan (2017) synonymized C. larreae under C. depilis, while making no comment about the male and queen differences. We have sequenced sympatric samples taken in Chihuahuan desert near Portal, Arizona, corresponding to the C. depilis colour phenotype (PSW14684) and the C. larreae colour phenotype (PSW15960 and PSW16636), and we find that they are positioned in different parts of the UCE phylogeny (Fig. 1). The C. larreae -like samples are sister to C. mutans, while the C. depilis - like sample clusters with other C. depilis populations from New Mexico, Arizona and California. Thus we have provisional evidence that there are indeed two species, with C. larreae actually being more closely related to C. mutans (with which it is allopatric) than to C. depilis. On the basis of univariate observations and bivariate plots we have been unable to discover diagnostic morphometric differences between the workers of C. depilis and C. larreae, but it is possible that a more detailed, multivariate analysis would permit discrimination of the workers of these two species. This was found to be effective, for example, to separate two closely similar sister-species in Europe, C. scutellaris and C. schmidti (Mayr, 1853) that also differ subtly in colour (Seifert, 2018). Distribution and biology: Crematogaster larreae was recorded by Buren (1968) from desert localities in west Texas, Arizona and California, nesting in the lower stems and roots of Larrea divaricata. The one nest series that we have collected (PSW15960) was in a similar situation in south-eastern Arizona. Buren (1968) further noted that C. larreae was often absent from localities with Larrea, and he suggested that competition with other desert-dwelling ants may restrict it to harsher, rockier sites. It is also interesting to note that the queens and males of C. larreae are smaller and shinier than those of C. depilis, suggesting perhaps an unusual mode of colony foundation.Published as part of 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), pp. 893-937 in Zoological Journal of the Linnean Society 194 on pages 917-918, DOI: 10.1093/zoolinnean/zlab04

Crematogaster opaca Mayr 1870

CREMATOGASTER OPACA MAYR, 1870 Crematogaster opaca Mayr, 1870: 992. Syntype worker, Tabukaya, Mexico, 1865 (Bilimek) (NHMW) (examined via AntWeb image: CASENT0919705) and syntype worker, Mexico (Sichel) (BMNH) (examined via AntWeb image: CASENT0902152); latter here designated lectotype. Crematogaster lineolata subsp. opaca Mayr; Emery, 1895: 283. Crematogaster opaca Mayr; Wheeler, 1919: 111. Crematogaster (Acrocoelia) lineolata subsp. opaca Mayr; Emery, 1922: 141. Crematogaster (Acrocoelia) opaca Mayr; Wheeler, 1934a: 139. Crematogaster (Crematogaster) opaca Mayr; Smith, 1958: 126. Discussion: Morgan & Mackay (2017) refer to a syntype worker of C. opaca in NHMW ‘collected by Professor Bilimek and Dr Sichel in México’. This statement is misleading because there is no single syntype collected by Bilimek and Sichel; their collections were separate. In the BMNH there is a syntype worker (here designated lectotype) (CASENT0902152) labelled ‘Mex.|Sichel’, while the NHMW syntype (now paralectotype) is labelled ‘ Mexico |Takubaya|Bilim. 65’. However, the important point is that these two specimens are almost certainly not conspecific. The Sichel specimen has the head, mesosoma, petiole and postpetiole densely reticulate-foveolate and opaque, and the gaster finely reticulate and sublucid; the promesonotum is evenly convex in profile and broad in dorsal view (pronotum width/head width ~0.62); the propodeal spine distance is relatively large (SPTD/HW ~0.49); and standing pilosity appears to be sparse (not visibly present on the mesosoma dorsum). The Bilimek specimen is more weakly sculptured with a correspondingly shinier integument, especially on the petiole, postpetiole and gaster; the promesonotum is somewhat flattened in profile and narrower in dorsal view (pronotum width/ head width ~0.53); the propodeal spine tips are less distant (SPTD/HW ~0.44); and standing pilosity is more conspicuous, being present on the mesosoma dorsum on both the pronotal humeri and the mesonotal declivity. Although in this study we are concerned primarily with the Crematogaster of America north of Mexico, we have decided to select a lectotype of C. opaca to assist future work. We designate the BMNH specimen as lectotype because it better matches the original description, which emphasizes the densely reticulate-punctate sculpture and the scarcity of standing pilosity (Mayr, 1870). Unfortunately the provenance of this specimen – other than Mexico – is unknown. Sichel evidently supplied the specimen to Mayr, but there is no evidence that he visited Mexico or anywhere else outside Europe during his lifetime (Mulsant, 1869), so the specimen would have been acquired from another collector, possibly de Saussure. The non-conspecific paralectotype is from Takubaya (= Tacubaya), a district of Mexico City, near Bilimek’s place of residence during his stay in Mexico (Roth, 1965: 346). There is a confusing array of C. opaca -like forms found in Mexico and Central America, showing considerable variation in sculpture, pilosity, configuration of the promesonotum, size of propodeal spines and petiole shape. More comprehensive sampling and careful study is necessary to determine how many species are present in this complex. These ants just barely enter the United States, in southern Arizona. Because of taxonomic uncertainty, we refer to the Arizona populations as Crematogaster sp. cf. opaca. These specimens are similar to the C. opaca lectotype with respect to integument sculpture, promesonotal shape (pronotum width/head width 0.59–0.62) and propodeal spine distance (SPTD/ HW 0.45–0.51), but they have more abundant standing pilosity (MSC 2–5, A4SC 10–18).Published as part of 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), pp. 893-937 in Zoological Journal of the Linnean Society 194 on pages 918-919, DOI: 10.1093/zoolinnean/zlab04

Taxonomy in the phylogenomic era: species boundaries and phylogenetic relationships among North American ants of the Crematogaster scutellaris group (Formicidae: Hymenoptera)

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: 893-937, DOI: 10.1093/zoolinnean/zlab04