Crematogaster maina Blaimer, 2013

Blaimer, Bonnie B. & Fisher, Brian L., 2013, Taxonomy of the Crematogaster degeeri-species-assemblage in the Malagasy region (Hymenoptera: Formicidae), European Journal of Taxonomy 51, pp. 1-64 : 39-43

Crematogaster maina Blaimer sp. nov.

urn:lsid:zoobank.org:act:A59911D0-2601-405F-91CF-355998892F4E

Figs 15-16

Diagnosis

Crematogaster maina sp. nov. is easily distinguished from other species in the C. degeeri -assemblage by its yellow body coloration. It is considerably smaller than C. bara sp. nov., which shares its yellow color (HW 0.60 - 0.86, WL 0.66 - 0.93 vs C. bara sp. nov. HW 0.87 - 1.03, WL 0.98 - 1.22) and shorter antennal scapes (SI 0.71 - 0.83 vs C. bara sp. nov. SI 0.91 - 1.01). Molecular sequence divergence to the remaining species ranges from 11.3 - 20.2 %.

Etymology

This species is named after its predominant distribution in the dry forests of Madagascar: maina is the Malagasy word for “dry.” The name is treated as a noun in apposition.

Type specimens

Holotype

Worker: pinned, CASENT0317758 , BBB246, ex dead twig above ground [imaged on AntWeb]; original locality label: M’dgascar: Toliara: PN Andohahela , p3: Ankasofotsy , 4.5 km W Ranopiso, S 25º00.820’, E 46º38.790’, 160 m, 21 Mar. 2010, transition forest, B.B. Blaimer, BBB#246; deposited at CASC.

Paratypes

4 workers, pinned, same collection and locality data as holotype. #1: CASENT0317789 , deposited at SAMC. #2: CASENT0317790 , deposited at MHNG. #3: CASENT0317791 , deposited at MCZC. #4: CASENT0317792 , deposited at UCDC.

Type locality

MADAGASCAR: Toliara: P.N. Andohahela (parcel 3): -25.0137, 46.6465, 160 m, dry forest/transition forest.

Other material examined

(BBBC, CASC, MCZC, PSWC): refer to Supplementary Material 1.

Worker

Measurements

(n = 21) [holotype] HW 0.60 - 0.86 [0.77]; HL 0.56 - 0.80 [0.74]; EL 0.13 - 0.20 [0.18]; SL 0.43 - 0.64 [0.59]; WL 0.66 - 0.93 [0.87]; SPL 0.05 - 0.12 [0.10]; PTH 0.12 - 0.21 [0.18]; PTL 0.19 - 0.27 [0.26]; PTW 0.26 - 0.36 [0.30]; PPL 0.10 - 0.19 [0.15]; PPW 0.21 - 0.34 [0.28]; LHT 0.44 - 0.64 [0.60]; CI 1.02 - 1.12 [1.04]; OI 0.20 - 0.26 [0.24]; SI 0.71 - 0.83 [0.80]; SPI 0.07 - 0.14 [0.11]; PTHI 0.63 - 0.81 [0.69]; PTWI 1.13 - 1.44 [1.13]; PPI 1.61 - 2.02 [1.84]; LBI 1.10 - 1.69 [1.45].

Description

( Fig. 15A - F ) Very small to small size (HW 0.60 - 0.86, WL 0.66 - 0.93).

Masticatory margin of mandibles with four teeth; head shape fairly quadrate or slightly wider than long (CI 1.02 - 1.12); posterior margin of head in full-face view laterally subangular or rounded, sometimes slightly medially depressed; occipital carinae distinct; antennal scapes usually about reaching head margin; midline of eyes situated at or slightly above midline of head in full-face view; eyes moderately large (OI 0.20 - 0.26) and only slightly protruding from head margin.

Pronotum laterally subangular, often carinate; usually promesonotal suture indistinct, and mesonotum forming a flat plane with respect to pronotum; in larger workers ( Fig. 15D - F ) promesonotal suture present, and mesonotum raised and anteriorly projecting over pronotum; mesonotum usually without a posterior face; mesonotum posterolaterally with raised carinae or sometimes small denticles, but not distinctly set off from propodeum, forming one convex outline with the latter in lateral view; metanotal groove very shallow, laterally bordered by carinae but not constricted; propodeal spines short (SPI 0.07 - 0.14), straight and spiniform; dorsal face of propodeum very short or absent; posterior face of propodeum usually gently sloping; petiole in dorsal view broadly or sharply flared and convex, dorsolaterally rounded, without posterolateral tubercules; subpetiolar process mostly present as sharp acute tooth; postpetiole very distinctly bilobed, separated by a broad median impression; subpostpetiolar process absent.

Head sculpture aciculate; pronotum costulate, carinulate or reticulate, propodeum often carinulate; rest of mesosoma, petiole, postpetiole reticulate; face usually with <ten erect longer setae, and regular shorter appressed pubescence; erect pilosity on promesonotum usually restricted to lateral margins, usually <ten setae; otherwise promesonotum dorsally with sparse appressed to subdecumbent pubescence; petiole and postpetiole usually with a pair of short erect setae posterolaterally, and shorter appressed pubescence; abdominal tergites and sternites four to seven with abundant, short, erect pilosity, and sparse appressed to decumbent pubescence throughout. Color uniformly yellow.

Queen

Measurements

(n = 5) HW 0.98 - 1.13; HL 1.04 - 1.17; EL 0.29 - 0.34; SL 0.66 - 0.73; MSNW 0.86 - 1.02; MSNL 0.96 - 1.05; WL 1.65 - 1.82; SPL 0.00; PTH 0.31 - 0.34; PTL 0.36 - 0.41; PTW 0.45 - 0.50; PPL 0.22 - 0.30; PPW 0.40 - 0.47; LHT 0.72 - 0.87; CI 0.94 - 1.00; OI 0.27 - 0.31; SI 0.61 - 0.66; MSNI 0.85 - 0.99; SPI 0.00; PTHI 0.83 - 0.90; PTWI 1.18 - 1.28; PPI 1.50 - 1.79; LBI 2.14 - 2.38.

Description

( Fig. 16A - C ) Very small to small size (HW 0.98 - 1.13, WL 1.65 - 1.82). With worker characters, except as follows.

Masticatory margin of mandibles with five teeth; antennal scapes usually not surpassing level of lateral ocelli; eyes moderately large (OI 0.27 - 0.31), situated slightly below midline of head in full-face view; head shape square or rectangular-elongate (CI 0.94 - 1.00); posterior margin straight.

Mesoscutum in dorsal view usually longer than wide (MSNI 0.85 - 0.99); dorsal face of propodeum short; propodeal spines or tubercules absent; petiole moderately to greatly flared, postpetiole with a complete, but superficial impression; subpetiolar process variable, usually absent.

Sculpture aciculate throughout; face usually with <ten longer erect setae and abundant, shorter, erect to suberect pilosity; mesonotum with abundant short, and scattered longer, erect setae; petiole and postpetiole with dense short suberect to decumbent pilosity, and postpetiole with additional longer dorso-posterior setae; abdominal tergites and sternites four to seven with sparse, scattered erect pilosity and regular appressed pubescence. Color as in workers; wings clear.

Male

Measurements

(n = 3) HW 0.57 - 0.59; HL 0.45 - 0.48; EL 0.22 - 0.23; SL 0.10 - 0.11; MSNW 0.67 - 0.74; MSNL 0.61 - 0.66; WL 1.19 - 1.24; SPL 0.00; PTH 0.17 - 0.20; PTL 0.22 - 0.24; PTW 0.22 - 0.25; PPL 0.12 - 0.15; PPW 0.25 - 0.27; LHT 0.60 - 0.64; CI 1.23 - 1.31; OI 0.48; SI 0.20 - 0.25; MSNI 1.02 - 1.18; SPI 0.00; PTHI 0.81 - 0.84; PTWI 0.93 - 1.17; PPI 1.74 - 2.02; LBI 1.94 - 2.03.

Description

( Fig. 16E - F ) Very small (HW 0.57 - 0.59, WL 1.19 - 1.24).

Mandibles very short and reduced, with one singular apical tooth; clypeus not much protruding; eyes fairly large (OI 0.48) and protruding, midline of eyes situated well below midline of head, almost extending to clypeal margin; antennae 12-segmented; head wider than long (CI 1.23 - 1.31); in full-face view ocellar triangle situated below posterior head margin, elevated with respect to rest of face; occipital carinae distinct.

Mesoscutum in dorsal view as wide as to a little wider than long (MSNI 1.02 - 1.18); scutellum in dorsal view broadly tapering from anterior to posterior end, dorsoposterior part rounded; metanotum protruding from below scutellum; dorsal face of propodeum short; propodeal spines absent; petiole in dorsal view oval, laterally rounded, in lateral view anteriorly greatly tapering; subpetiolar process absent; postpetiole fairly flat and short, lacking median impression.

Head sculpture reticulate; mesoscutum with very fine longitudinal carinulae; otherwise sculpture more or less shiny to aciculate; sparse appressed to decumbent pubescence on head and mesosoma, a few short erect setae on face may be present; rest of pilosity similar to queens. Color pale to light brown.

Distribution and biology

MADAGASCAR, COMOROS, MAYOTTE. Crematogaster maina sp. nov. is a very abundant species at low elevations throughout the dry forests, littoral forests and spiny forests of Madagascar, the Comoros Islands and Mayotte ( Fig. 16D ). It has also been collected at higher elevations in more humid habitats (up to 1410 m), but we suspect that some of these occurrences could represent tramp-like introductions to suboptimal habitats. Crematogaster maina sp. nov. is commonly found in sympatry with C. dentata stat. nov., C. ramamy sp. nov., C. tricolor stat. rev. and C. lobata , and at some locations is also known to co-occur with C. mafybe sp. nov., C. sewellii , C. bara sp. nov. and C. masokely sp. nov. The species is most often encountered nesting arboreally in dead twigs or branches. This species has only been found at baits during the night and has never been observed foraging during the day. We conclude that it is nocturnal, which would explain its pale coloration.

Comments

As discussed above, the two individuals of C. maina sp. nov. sampled for the genetic analysis are highly divergent from all but one of the rest of the Madagascar samples (13.3 % maximal distance; Table 3 ), and further do not group as closest relatives to these in our analysis ( Figs 1 and 2A ). However, since we cannot find conclusive morphological evidence to distinguish the island population from the one on Madagascar, we refrain from splitting the two. With only three individuals sampled, spurious sequences (discussed below) are a possibility.

Figures

Fig. 15. Crematogaster maina sp. nov., workers. A-C. Worker (CASENT0317758). A. Full-face. B. Profile. C. Dorsal. D-F. Worker (CASENT0317760). D. Full-face. E. Profile. F. Dorsal.

Fig. 16. Crematogaster maina sp. nov., queen, male and distribution. A-C. Queen (CASENT0485040). A. Full-face. B. Profile. C. Dorsal. D. Species distribution. E-F. Male (CASENT0455252). E. Full-face. F. Profile.

Fig. 1. Mitochondrial phylogeny of species in the Crematogaster degeeri-assemblage. Results of Bayesian inference based on 592 bp of COI, summarized as a consensus tree in MrBayes. Support values in black represent posterior probabilities (pp), those in blue ML (Maximum Likelihood) bootstrap values>70, and those in red ML bootstrap values<70. Values pp <0.96 are not shown; nodes not present in the ML analysis are represented by a dash instead of a bootstrap value. The scale bar shows nucleotide changes per base pair. Long branches subtending the outgroup taxa C. madecassa Emery, 1895, C. ranavalonae Forel, 1887 and C. hova-complex have been shortened. Appended numbers on taxon labels represent CASENT#’s of respective voucher specimens.

Fig. 2. Relatedness of populations between Madagascar and the wider Malagasy region. Subsets of the same phylogeny as shown in Fig. 1, with broad geographical origin of sequenced individuals mapped onto the tree for: A. Crematogaster maina sp. nov. B. Crematogaster dentata stat. nov. C. Crematogaster tricolor stat. rev. Support values in black represent posterior probabilities (pp), those in blue ML bootstrap values> 70 and those in red ML bootstrap values <70. Values pp <0.96 are not shown; nodes not present in the ML analysis are represented by a dash instead of a bootstrap value. The scale bar shows nucleotide changes per base pair. Distance between Madagascar and Islands is not drawn to scale. Appended numbers on taxon labels represent CASENT#’s of respective voucher specimens.