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Research Article
Schievitermes globicornis, a new genus and species of Termitinae (Blattodea, Termitidae) from French Guiana
expand article infoYves Roisin‡
‡ Université Libre de Bruxelles, Brussels, Belgium

Corresponding author: Yves Roisin ( yves.roisin@ulb.be )

Academic editor: Eliana Cancello
© 2022 Yves Roisin.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation: Roisin Y (2022) Schievitermes globicornis, a new genus and species of Termitinae (Blattodea, Termitidae) from French Guiana. ZooKeys 1125: 103-114. https://doi.org/10.3897/zookeys.1125.91124
ZooBank: urn:lsid:zoobank.org:pub:4E1FBE4F-E1C9-46C2-89AE-28794DD229F7
Open Access

Abstract

Asymmetrical snapping mandibles have evolved several times in termites. In the Neotropics, asymmetrical snapping mandibles are found in soldiers of four genera: Neocapritermes, Planicapritermes, Cornicapritermes and Dihoplotermes. Here, I describe Schievitermes globicornis, new genus and species, from French Guiana. This genus is characterized by an absence of a frontal prominence and slightly asymmetrical mandibles in the soldier caste. The morphology and anatomy of the worker reveal a wood-based diet, and suggest that Schievitermes, Planicapritermes and Neocapritermes constitute a monophyletic group, which is consistent with mtDNA data.

Keywords

Isoptera, Neocapritermes, Neotropical region, new species, Planicapritermes, termite

Introduction

Soldiers with snapping mandibles are commonplace in termites, and there is growing evidence that this defensive device evolved several times in the family Termitidae (Inward et al. 2007), as well as once in Kalotermitidae (Scheffrahn et al. 2018). When the soldier presses its mandibles against each other, they accumulate elastic energy, which is converted into kinetic energy as soon as the mandible shafts slip past each other, delivering a very quick and powerful strike (Seid et al. 2008). Although termite mandibles always display some degree of asymmetry, some snapping soldiers can be catalogued as symmetrical because their mandibles both show a similar elongated shape and can deliver a symmetrical blow (Deligne 1971). In asymmetrical snappers, the left mandible is bent outwards in its basal part before straightening apically, whereas the right mandible is almost straight, or slightly bent inwards. When mandibles are pressed against each other, the curved part of the left mandible functions as a spring, concentrating elastic energy in preparation for an asymmetrical blow (Deligne 1971).

Snappers are especially diverse in the Oriental region, but several genera are known from the Neotropics: Termes (also present in the Old World tropics), Cavitermes, Palmitermes, Crepititermes and Inquilinitermes are symmetrical snappers, whereas Neocapritermes, Planicapritermes, Cornicapritermes and Dihoplotermes are asymmetrical ones (Krishna 1968). Asymmetrical snappers appeared separately in the Old World (Pericapritermes and related genera), in Madagascar (Capritermes) and in the Neotropics, where Inward et al. (2007) suggested that they evolved independently twice, once in Planicapritermes and once in Neocapritermes. Although more recent studies have established a close relationship between Planicapritermes and Neocapritermes, forming the sister clade to the symmetrical snapper Crepititermes (Bourguignon et al. 2017), it remains that asymmetrical snapping must also have evolved independently in the neotropical Termes group (Dihoplotermes and probably Cornicapritermes). Bourguignon et al.’s (2017) study included a taxon from French Guiana provisionally labelled “G683 Neocapritermes sp. H”, which displayed only slightly asymmetrical snapping mandibles and whose mtDNA appeared closer to Planicapritermes than to Neocapritermes. Reexamination of this sample with more recent collections from French Guiana revealed that this species does not fit into any of the abovementioned genera. I describe it hereunder as Schievitermes globicornis, gen. nov., sp. nov., and discuss its relationships.

Material and methods

Dissections were made in alcohol. Guts in situ were drawn with a camera lucida. Detached pieces such as mandibles or enteric valves were directly mounted on microscope slides in PVA medium (BioQuip Products Inc.).

Images of entire specimens are multi-layer compilations obtained with a Zeiss Discovery V12 steromicroscope equipped with an AxioCam ICc3 camera and controlled by AxioVision release 4.8.3 software. Images are compilations of series of successive stepwise focused photographs. Images of microscope slide preparations were taken with a Leica DFC450C camera mounted on a Leica DM5500B microscope and operated with Leica Application Suite v.4.12.0 software. Enteric valves and hindgut wall sections were observed under phase-contrast illumination.

Terminology follows that of Sands (1972) for mandible dentition and that of Noirot (1995, 2001) for gut anatomy. Measurements, as described in Roonwal (1969), were taken to the nearest 0.005 mm with a Wild MMS 235 length-measuring set fitted to a Wild M6 stereomicroscope.

Taxonomy

Schievitermes gen. nov.

https://zoobank.org/9B8C1A8B-047A-4CEC-A182-0288A0593CF4

Remark

This genus is presently monotypic.

Type species

Schievitermes globicornis sp. nov.

Description

Imago : only known from a single queen. See species description.

Soldier (Figs 1–4): Head capsule (Figs 1–3) subquadrangular with rounded corners, about twice as long as broad, bearing numerous (~100) setae. Mandibles approximately as long as head capsule, rather thick, of the snapping type. Right mandible almost straight, only slightly curved inwards. Left mandible slightly but distinctly sinuous: outer margin slightly concave near base, convex in middle, then concave again at level of contact with right mandible, then curved inwards at tip. Tips of both mandibles hooked, turned about 60° inwards. Antennae of 13 articles, apical article reaching beyond left mandible tip; article 3 distinctly globular, as broad as article 1 and broader than all other articles. Labrum (Fig. 4) with nearly parallel sides, anterior margin sinuous, convex in middle, bearing a few long bristles, anterior corners rounded. Frons without projection.

Worker (Figs 5–9, 12–13, 15–17): Monomorphic. Head capsule whitish, bearing many setae. Mandibles (Fig. 5) of the wood-feeding type. Left mandible: distance between teeth A–M1+2 approximately half the distance M1+2–M3. M3 well-marked, premolar tooth (sensu Deligne 1999) blade-like, molar ridges well developed. Right mandible: distance between teeth A–M1 short, M2 well-marked, molar ridges well developed. Crop moderately developed, gizzard (Figs 6, 7) of the generalized type (Noirot 2001), cuticular armature limited to small pectinated scales on the pulvilli (Fig. 7). Mixed segment long, mesenteric tongue bilobate distally (Fig. 8). Ileum (P1) slightly dilated, narrowing into P2. Enteric valve (P2) funnel-like, conical at end of P1, becoming a narrow tube at junction with P3. Enteric valve armature (Fig. 9) consisting in two rings of spine-bearing areas, the proximal one in the conical section of P2, formed by three ovoid cushions alternating with elongated ones, all bearing small triangular spines; distal ring within the narrow tubular section, formed by six alternating short and long cushions bearing thin, curved spines. Paunch (P3) voluminous, with wall bearing numerous small spines, longer in rounded posterior section near entrance of P2 (Fig. 12), short and often pectinated in anterior section narrowing towards P4 (Fig. 13).

Etymology

From local Brussels dialect schieve = not straight, askew, and Latin termes = termite. The name refers to the slight grade of asymmetry displayed by soldier mandibles.

Diagnosis

Soldier : Among neotropical snappers, the absence of a frontal projection distinguishes Schievitermes from Termes, Inquilinitermes, Cavitermes, Palmitermes, Dihoplotermes, and Cornicapritermes. Planicapritermes has a characteristic flattened head capsule and strongly asymmetrical mandibles. Schievitermes differs from Crepititermes by its thicker mandibles with a slight, but distinct asymmetry, and globular third antennal article. Neocapritermes species are consistently larger (head width > 1 mm), have more antennal articles (15–16 vs 13) and their mandible asymmetry is always more pronounced (Krishna and Araujo 1968; Constantino 1991; Bandeira and Cancello 1992).

Figures 1–3. 

Schievitermes globicornis sp. nov.: soldier head 1 from above 2 from below 3 from left.

Figures 4–7. 

Schievitermes globicornis sp. nov.: 4 labrum of soldier 5 worker mandibles, from above 6 gizzard of worker, complete, spread on slide (phase-contrast illumination) 7 gizzard of worker, detail of pulvillus (phase-contrast illumination).

Worker : Mandibles are of the wood-feeding type, as in Neocapritermes and Planicapritermes, with a short space between apical and anterior marginal teeth, and well-developed molar ridges. Termes (with the exception of the wood-feeding species, T. hispaniolae (Banks, 1918)), Crepititermes, Inquilinitermes, Cavitermes, Palmitermes, Dihoplotermes and Cornicapritermes have mandibles of the soil feeding type, with a broad space between apical and anterior marginal teeth, and reduced molar ridges. The digestive tube of Schievitermes is similar to that of Planicapritermes, but the bilobed apex of the mesenteric part of the mixed segment is distinctive. Neocapritermes also possesses two mesenteric lobes, but the mixed segment is shorter and the mesenteric lobes are larger and more widely separated (Constantino 1998; Almeida-Azevedo et al. 2021). The enteric valve armature of Schievitermes is similar to that of Planicapritermes (Figs 10, 11), apart from minor differences in the ornamentation of spiny areas. Cuticular differentiations within P3 of Schievitermes are intermediate between the long spines and filaments observed in Neocapritermes (Noirot 2001) and the tiny spines present in Planicapritermes (Noirot 2001; Fig. 14).

Figure 8. 

Schievitermes globicornis sp. nov.: camera lucida drawings of worker gut in situ. From left to right: viewed from above, right, below, left. Mesenteron stippled.

Most workers show signs of dehiscence between metanotum and first abdominal tergite, ranging from a short slit-like aperture bordered by brown sclerotic marks (Fig. 15) to a broad opening through which the whole anterior part of the gut protrudes (Figs 16, 17).

Schievitermes globicornis sp. nov.

https://zoobank.org/6D760044-34C4-47E0-8FB9-C3542473928B

Material examined

Holotype : soldier. French Guiana, Petit Saut Dam Road, Carbet Maman Lézard, 05.0672°N, 52.9992°W, from nest among tree roots, 20.i.2012 (coll. Y. Roisin – accession G683). Paratypes: soldiers and workers from same colony as holotype. Worker’s mtDNA sequence deposited in GenBank under label Neocapritermes sp. H TB-2017 isolate G683, accession KY224444 (Bourguignon et al. 2017). From other colonies than holotype: French Guiana, Laussat (N1 road, PK194), forest on white sands, 05.4698°N, 53.5748°W, small nest in rotten stump, with queen, soldiers and workers, 27.i.2020 (coll. Y. Roisin, N. Fontaine, A. Dumortier – accession G20-12); Mana Road (D8, PK1-2), forest on white sands, 05.5125°N, 53.5504°W, soldiers and workers in dead wood on the ground, 27.x.2021 (coll. Y. Roisin, N. Fontaine, J. Timmermans – accession G21-54). Type material to be deposited in the Royal Belgian Institute for Natural Sciences, Brussels, Belgium.

Figures 9–14. 

Proctodeal wall ornaments under phase-contrast illumination 9 Schievitermes globicornis sp. nov., worker enteric valve, spread on slide 10, 11 Planicapritermes planiceps (Emerson, 1925), worker enteric valve, spread on slide; proximal spiny areas and detail of distal spiny ridges, respectively 12, 13 Schievitermes globicornis sp. nov., ornamentation of worker paunch wall, in bulbous posterior part and narrower anterior section, respectively 14 Planicapritermes planiceps, ornamentation of worker paunch wall.

Description

Imago (Figs 18–20): caste only known from single queen from colony G20-12. This individual was physogastric, with partly depigmented eyes indicating a long underground life. Other body parts were probably of paler pigmentation than in swarming alates as well. Head capsule medium brown, postclypeus, pronotum and other tergites lighter. Antennae broken, 9–11 articles remaining, article 3 narrower and shorter than 2 and 4. Fontanelle hyaline, ovoid, about 45 µm long by 30 µm wide. Head capsule regularly rounded behind. Compound eyes medium-sized, ocelli large, separated from eyes by less than their own width. Pronotum rounded laterally and posteriorly, with a distinct notch behind. Measurements (in mm; numbers between brackets refer to list of measurements proposed by Roonwal 1969): Head length to anterior margin of postclypeus [8]: 0.770; head width, with eyes [17]: 0.810; head width, between eyes [52]: 0.595; eye maximum diameter [48]: 0.260; ocellus maximum diameter [55]: 0.115; ocellus-eye distance [57]: 0.035; pronotum length [65]: 0.425; pronotum width [68]: 0.635; hind tibia length [85]: 0.820.

Figures 15–17. 

Workers of Schievitermes globicornis sp. nov. fixed at various stages of abdominal dehiscence 15 linear crack (arrow) behind rear margin of metanotum 16 gut protruding through crack 17 anterior part of the gut completely extruded.

Figures 18–20. 

Queen of Schievitermes globicornis sp. nov. 18 head from above 19 oblique view of head 20 pronotum. The three figures are at the same scale.

Soldier (Figs 1–4): Head capsule yellow-brown. Mandibles black, turning brown near base. Antennae yellow-brown. Tibial spurs 3:2:2, anterior spur of fore leg about half the length of the other two.

Measurements of 10 soldiers from three colonies (in mm; numbers between brackets refer to list of measurements proposed by Roonwal 1969): Total head length, including mandibles (held straight forward in measured individuals) [4]: 2.535–2.775; length of head to lateral base of mandibles [5]: 1.320–1.470; head width [17]: 0.700–0.755; length of left mandible [37]: 1.255–1.330; length of right mandible [37]: 1.205–1.295; length of postmentum along median line [61]: 0.800–0.930; maximum width of postmentum [62]: 0.235–0.280; minimum width of postmentum [63]: 0.145–0.175; pronotum width [68]: 0.470–0.510; length of hind tibia [85]: 0.575–0.635.

Worker (Figs 5–9, 12–13, 15–17): Antennae of 13 articles. Tibial spurs 2:2:2. Head width of 20 workers from three colonies: 0.640–0.700 mm.

Etymology

from Latin globus = globe, sphere, and cornu = horn, antenna; the specific epithet refers to the globular shape of the third antennal article of the soldier.

Discussion

Morphologically, Schievitermes appears closest to either Planicapritermes or Neocapritermes. The three genera share asymmetrical snapping mandibles and absence of a frontal projection in the soldier, and worker mandibles revealing wood- or soil-wood interface-feeding habits. Schievitermes soldier head and mandible shape appears plesiomorphic with respect to the conspicuously asymmetrical mandibles of Planicapritermes and Neocapritermes, and the flattened head and body of the former. In the worker, Schievitermes is very similar to Planicapritermes by its long mixed segment, but the mesenteric lobes at the end of the mixed segment appear intermediate between Planicapritermes and Neocapritermes. The well-separated lobes of Neocapritermes probably represent a derived condition, but the partially bilobed mesenteric tongue of Schievitermes might be plesiomorphic, as it appears similar to the condition observed in Microcerotermes (Roisin and Pasteels 2000). The enteric valve armature is also very similar in Schievitermes and Planicapritermes, whereas distal cushions in Neocapritermes species are swollen and heavily armed with spines, which probably constitutes a derived trait. The three genera share the presence of numerous spines on the internal wall of P3, although this armature is more complex and comprises longer spines in Neocapritermes (Noirot 2001).

Complete mitochondrial DNA sequences have now confirmed the close relationship between Neocapritermes and Planicapritermes (Bourguignon et al. 2017), as proposed by earlier authors (Krishna 1968; Constantino 1998) but in contrast with the preferred tree of Inward et al. (2007), in which Planicapritermes joined a morphologically and zoogeographically improbable lineage including Orthognathotermes and Globitermes; however, several nodes among the Termitinae were weakly supported, and Inward et al. (2007) did not discard the possible monophyly of Neocapritermes + Planicapritermes. This new genus Schievitermes clearly belongs in the Neocapritermes + Planicapritermes clade, in which it seems to come closer to Planicapritermes in accordance with morphological and anatomical characters.

Acknowledgements

I thank the staff of the HYDRECO lab at Petit Saut (R. Vigouroux and the late P. Cerdan) for logistic help in French Guiana. G. Josens (ULB) and P. Martin (RBINS) helped with microphotography. Funding was provided by the F.R.S.-FNRS, Belgium (grants 2.4594.12 and J.0180.20).

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