Zikanita Lane, 1943

Nascimento, Francisco E. de L., Santos-Silva, Antonio & Barclay, Maxwell V. L., 2019, On the tribal allocation of Cosmotomidius Melzerı 1931 ı descriptions of new taxa of Acanthoderini and notes on some tribes of Lamiinae (Coleoptera: Cerambycidae), Journal of Natural History 53 (11), pp. 705-723 : 713-717

On Zikanita Lane, 1943

( Figures 2 (a – d), 3(a – g), 4(a – f))

Zikanita Lane, 1943: 261 ; Monné, 2018: 310 (cat.).

According to Lane (1943, p. 261) on Zikanita (translated): ‘ Very close to Cosmotomidius Melzer, 1931 , from which differs as follows: 1) scape and antennomere IV subequal in length, the antennomere III the longest; 2) mesoventral process with a conspicuous, rounded tubercle ’. However, in the description of Z. perpulchra, Lane (1943, p. 264) pointed out (translated):

The specimen [paratype] from Santo Amaro shows signs of precarious [sic] development; the discal tubercles of the pronotum, the elytral carinae, and the tubercle of the mesoventral process are poorly developed; the antennomere III of the antennae is subequal in length to the scape and to the antennomere IV.

This specimen is considered by us to belong to a different species. Furthermore, the existence of a specimen that does not agree with the generic description of Zikanita makes it controversial.

Machado and Monné (2009, p. 332) reported:

Cosmotomidius is similar to Zikanita Lane, 1943 in respect to the presence of abundant long hairs covering the body, pronotum with median tubercles, sides of prothorax with tubercles, and elytra with a median crista near the base. Cosmotomidius differs from Zikanita by the pronotum with a row of coarse punctures on the posterior and anterior margins, the mesosternal process without tubercles, and the elytra with black suberect setae. In Zikanita [ Z. perpulchra Lane, 1943 ] the pronotum has moderately coarse and sparse punctures, but they are organized in a row only on the posterior margin; the mesosternal process has tubercles; and the elytra lack black suberect setae.

According to Touroult et al. (2010, p. 193), who transferred Cosmotomidius to Pogonocherini (translated): ‘ The original diagnosis of the genus Zikanita indicates two precise criteria of identification ( Lane 1943, p. 261): scape and antennomere IV subequal, III the longest, and mesoventral process provide with a rounded and conspicuous tubercle, which make it possible to distinguish it from the close genus Cosmotomidius Melzer, 1931 ’; and ‘ As observed by Lane (1943) and Machado and Monné (2009), Cosmotomidius is close to Zikanita , which we maintain for the moment in the tribe Acanthoderini . The differences are in the mesoventral process (tuberculate in Zikanita ) and the ratio between antennomere III and IV (III longer or subequal to IV in Zikanita ) ’ ( Touroult et al. 2010, p. 194). However, as pointed out by Machado and Monné (2011), and also in the original description of the genus, these two features are variable in Zikanita . For example, the tubercle of the mesoventral process is absent in Z. argenteofasciata ( Figure 2 (c,d)) ( Tippmann 1960), nearly absent in Z. biocellata ( Tippmann, 1960) ( Figure 2 (a,b)), slightly elevated in the new species described here, and extremely elevated in Z. perpulchra ( Lane, 1943) .

Later, Machado and Monné (2011, p. 67) reported:

Zikanita differs from Cosmotomidius in total length, which reaches almost 20 mm, the elytra are 1.6 × wider than the prothorax at the base and the antennae are longer, exceeding the elytral apices at antennomere VII in males and VIII in females. In Cosmotomidius ( Machado and Monné, 2009, Figs 2 , 5 ) the total length does not exceed 14 mm, the elytra are 1.4 × wider than the prothorax at the base and the antennae exceed the elytral apices at antennomere VIII or IX in males and IX or X in females.

In the key to species of Zikanita, Machado and Monné (2011, p. 67) clearly contradicted

Lane (1943), Machado and Monné (2009) and Touroult et al. (2010):

‘ 1. Intercoxal process of mesosternum tuberculate.. .... ……………………… 2

-Intercoxal process of mesosternum planar.. .. ………………………………… 3 ’

To summarise, following Machado and Monné (2011), Zikanita differs from Cosmotomidius , but not by the features pointed out in the original description, or by Machado and Monné (2009) and Touroult et al. (2010).

Actually, the antennae in males of Cosmotomidius reach the elytral apex before the apex of the antennomere VI ( C. setosus , C. nigrisetosus Touroult et al., 2010 , C. morvanae Touroult et al., 2010 , C. vincus Machado and Monné, 2009 ) or before the apex of antennomere V ( C. egregius ( Martins and Galileo, 2007)) . In females of Cosmotomidius ( C. setosus ), the antennae reach the elytral apex at the base of antennomere VII. In males of Zikanita , the antennae are proportionally shorter than in Cosmotomidius , and reach the elytral apex ( Z. perpulchra ) at the basal third of VIII (apparently, it is the same in the holotype male of Z. biocellata ( Tippmann, 1960)) . In females of Zikanita , the antennae are considerably variable in length, and may reach the elytral apex from the apex of antennomere VIII to the apex of antennomere X. As for the proportions between the width of the posterior area of the prothorax and the humeral area, we agree with Machado and Monné (2011). The only exception is found in C. egregius , originally described in Zikanita . In this species, the humeral width is about 1.53 times greater than posterior margin of the prothorax, being intermediate between those of the remaining species of Cosmotomidius and those of Zikanita . However, the antennae in males of C. egregius are proportionally much longer than in males of Zikanita . The other feature pointed out by Machado and Monné (2011) total length of the species, is now less reliable, since the new species of Zikanita described here is less than 14 mm long.

As an additional feature separating the current species placed in Zikanita from those of Cosmotomidius , we report that all species of the former have a sub-reniform dark pubescent macula on each side of the pronotum, which is absent in Cosmotomidius .

Figures

Figure 2. (a,b) Zikanita biocellata, female: (a) dorsal habitus; (b) ventral habitus. (c,d) Zikanita argenteofasciata, female: (c) dorsal habitus; (d) ventral habitus.

Figure 5. Cosmotomidius setosus: (a,b) lectotype: (a) dorsal habitus; (b) labels. (c,d) Cosmotomidius setosus, specimen deposited at BMNH, former Fry collection: (c) dorsal habitus; (d) labels.