Mariconitermes Fontes and Vulcano

Grimaldi, David A., Engel, Michael S. & Krishna, Kumar, 2008, The Species of Isoptera (Insecta) from the Early Cretaceous Crato Formation: A Revision, American Museum Novitates 3626 (1), pp. 1-32 : 3-5

Genus Mariconitermes Fontes and Vulcano

Mariconitermes Fontes and Vulcano, 1998: 269 . Type species: M. talicei Fontes and Vulcano, 1998: 270 . By original designation.

DIAGNOSIS (REVISED): Imago: Easily distinguished from other Crato Formation termites by the broad, rounded head, the characteristic, trapezoidal-shaped pronotum, and the large size (12–15 mm body length). Only Cratomastotermes wolfschwenningeri (below) is larger than M. talicei , by approximately 3–4 mm, but Cratomastotermes has a distinctive, extremely broad pronotum. Tarsi pentamerous, pretarsus with arolium; cercus with three segments, length of apical cercomere more than twice that of basal ones; wing with extensive reticulations and well-developed radial field having five large branches.

TABLE 1 Measurements of Crato Formation termites (in millimeters)

DESCRIPTION: Head: Robust, rounded, posterior border apparently gently rounded, lateral borders convex, gently rounded. Right mandible apparently with two marginal teeth, second larger than first and separated from first by distance greater than its length; subsidiary tooth not evident (preservation poor, so not definitively absent); apical tooth longer than either marginal tooth. Left mandible with long apical tooth and at least one sharply pointed marginal tooth (remainder of mandibular margin poorly preserved so presence of a second marginal tooth cannot be determined with confidence, but apparently with a putative base for second marginal tooth). Antenna moniliform, with $ 32 antennal segments (left antenna of AMNH- SAI2 with 31 segments, right one with 32); first article (scape) slightly longer than combined lengths of second and third articles. Compound eye circular to semicircular, moderate-sized, separated from posterior border of head by more than 1.5 X length of eye. Yshaped coronal ecdysial line present. Ocelli and fontanelle apparently absent. Thorax: Pronotum flat and subtrapezoidal, anterior margin about as wide as head, posteriorly narrower than head; anterior margin relatively straight, with anterolateral corners pronounced and acute; lateral margins relatively straight to slightly concave, converging posteriad, posterolateral corners gently rounded, posterior margin relatively straight. All tarsi completely pentamerous; tibial spur formula possibly 3-3-3, tibial macrosetae (‘‘spines’’) unapparent; arolium small (evident in some specimens). Forewing relatively long and broad; membrane with extensive network of coarse, raised reticulations throughout, especially on apical half of wing. Forewing scale quite large, with humeral (anterior) margin gently but distinctly arched, basal suture slightly convex, claval fissure (CuP) meeting basal suture before posterior margin, all veins originating within wing scale, slight reticulations within scale between posterior vein stems. Vein Sc simple, terminating on costal margin near one-third wing length; radial field relatively broad, gradually and gently expanding to encompass wing apex; R 1 simple, terminating on costal margin just beyond wing midlength; R 2 simple for most of its length, either simple or with a single branch near costal margin shortly before termination along costal margin, termination near apical third of wing length; Rs branching near wing midlength, branches with some secondary branches; course and branching of M not completely evident in preserved material, apparently terminating slightly posterior to wing apex and with a few branches in at least apical half of wing; course and branching of CuA not evident in preserved material. Abdomen: Abdominal styli not evident, possibly absent. Cerci short, trimerous, segments relatively elongate; distal segment approximately twice the length of either proximal segment, cylindrical in form.

COMMENTS: Fontes and Vulcano (1998) indicated that the holotype of M. talicei had apparently five cercal segments, although SEM revealed that only three segments are present in the two AMNH specimens where cerci are exposed (fig. 2C, D) (Fontes and Vulcano may have assumed that the basalmost article was actually three separate articles). The presence of three cercomeres was cited by Bechly (2007), though none of the SMNS specimens have the cerci preserved. In some primitive termite species the number of cercal segments sometimes varies by one or two (e.g., Archotermopsis wroughtoni Desneux with 5–7 articles: Emerson, 1933), but this is uncommon and does not appear to be the situation for M. talicei . Scanning electron microscopy has revealed that the apical cercal segment can have some annulations, making it appear as if it were divided into several articles (fig. 2C). The apical cercal segment of M. talicei is also characteristically elongate relative to the preceding articles (present across all of the specimens, including the holotype). Cercal segmentation has particular phylogenetic significance (Engel, Grimaldi, and Krishna, in prep.), so it is important to scrutinize this feature in fossils.

Mariconitermes talicei Fontes and Vulcano

Figures 1–4

Mariconitermes talicei Fontes and Vulcano, 1998: 270 . By original designation. Bechly, 2007: 259.

DIAGNOSIS: As for the genus (see above).

HOLOTYPE: No. 5006 in the private collection of M. A. Vulcano, São Paulo, Brazil . Paratype no. 5007, ibid.

DESCRIPTION: Imago: The above description characterizes the genus and species (ICZN, 1999: Art. 13.4). To the generic account can be added the metrics provided in table 1.

MATERIAL EXAMINED: Six imagoes: AMNH Sa-I2, Sa-I5, ROM 1767, ROM 1749 (possibly ROM 1754, but poorly preserved), SMNS 66193, SMNS 66194 ( SMNS 66198 labelled as? Mariconitermes but is far smaller (forewing length 9.3 mm, vs. 12–14 mm, and too poorly preserved for definitive identification], ZMHB MBI.2062 [possibly ZMHB MBI.2209 and 2063, but poorly preserved]). Early Cretaceous (Aptian), Crato Formation, Brazil, Araripe Basin.

Figures

Fig. 1. Mariconitermes talicei Fontes and Vulcano. Photomicrographs of well-preserved specimens, with select details. A. AMNHSaI-2. B. AMNHSaI-2 head. C. AMNHSaI-5 legs. D. AMNHSaI-5. E. AMNHSaI- 5 cerci. F. SMNS 66192. G. SMNS 66193.

Fig. 2. Mariconitermes talicei, scanning electron micrographs of select details. A. Right eye and inner border, showing absence of ocellus. B. Mid left tarsus and tibial apex of AMNHSaI-5. C. Right cercus, AMNHSaI-3, showing fine annulations. D. Right cercus, AMNHSaI-5.

Fig. 3. Mariconitermes talicei, variation in wing venation. A. SMNS 66193, left forewing. B. SMNS 66193 right forewing. C. SMNS 66194, right forewing (reticulations omitted, with anal margin of left forewing shown as preserved). All to the same scale.

Fig. 4. Mariconitermes talicei. A. Reconstruction of habitus based on a series of specimens (hind wings not shown). B. Base of forewing of AMNHSaI-4. C–D: Details of tarsi. C. AMNHSaI-5. D. AMNHSaI-2.