Copelatus (Bemaraha): sp. 1

Ranarilalatiana, Tolotra, Raveloson Ravaomanarivo, Lala Harivelo & Bergsten, Johannes, 2019, Taxonomic revision of the genus Copelatus of Madagascar (Coleoptera, Dytiscidae, Copelatinae): the non- erichsonii group species, ZooKeys 869, pp. 19-90 : 19

Copelatus (Bemaraha): sp. 1 Fig. 8C

Type material studied

[of C. nodieri & C. nodieri var. somalicus for comparison with sp1]: -LT♀ (MNHN, "coll. Guignot"): // Data in NHRS | JLKB | 000065417 // Haut Sénégal | Khayes | Dr. Nodier | 11-12. 1881 // Type [red label] // ♀ [female symbol] // nodieri // Coll. Guignot // -PLT♀ (MNHN, "coll. Régimbart”): // Data in NHRS | JLKB | 000065418 // Khayes | H Senegal // Nodieri Reg // Coll. Régimbart // -PT♀ (MNHN, "coll. Guignot"): // Data in NHRS | JLKB | 000065419 // SOMALIA IT. | Belet Amin. | (Giuba) Apr. 1923 | Patrizi // Paratype [red label] // ♀ [female symbol] // Museo Civico | di Genova // Copelatus | nodieri | var. ♀ somalicus | Guign. Paratype // var. somalicus | Det. J. Bergsten, 2011 //

Additional material studied.

Mahajanga. Melaky: Antsalova: -1♀ (CAS): // CASENT 8135000 // Madagascar: Mahajanga | Prov Parc National Tsingy | de Bemaraha, 10.6 km ESE | 123° Antsalova, Elev 150 m | 16-20 November 2001 // 19°42'34"S, 44°43'5"E |coll: Fisher, Griswold et al | California Acad. Of Sciences | sifted litter - tropical dry forest | on Tsingy, BLF4432 // Copelatus sp. nov. | C. pulchellus complex | Det. Ranarilalatiana | & Bergsten, 2019 //

Description.

This species is broad and oval in body shape and belongs to the pulchellus complex. Three species of the pulchellus complex are known from Madagascar, C. pulchellus , C. marginipennis , and C. mahajanga . It is most similar to C. marginipennis based on its very short and broad body shape. However, it differs in being almost entirely black dorsally, only slightly rufous laterally on the elytra, pronotum, and part of head. As such it is most similar in colouration to the dark form of C. pulchellus on Madagascar, but the body is shorter and broader. A second distinguishing characteristic is the very abbreviated first stria, present only in the posterior third, hence abbreviated even more than in C. mahajanga . Finally, this female specimen has fine but dense striolations mediolaterally on the elytra, and is densely punctured in the posterolateral corners of the pronotum ( Fig. 8C ). This undoubtedly represents a fourth species of the group present on Madagascar, which was confirmed based on the DNA data sequenced from this unique dry-preserved female specimen ( Figs 2 , 3 ). It is intriguing that it was collected through litter sifting on the tsingy (stone carst formations) of Tsingy de Bemaraha NP.

It is plausible that it was one or several female specimens of this species that Guignot (1960:101) referred to as Copelatus nodieri var. ♀ somalicus , a species described from Mali, continental Africa. He recorded it from "Andobo, 190 m, foret Antsingy, dct Antsalova", the same locality as for our female ( Fig. 11D ). We consider Guignot’s record as based on a misidentification and remove C. nodieri from the list of Copelatus species known from Madagascar after having studied the type material of both C. nodieri Régimbart, 1895, described from Somalia and of C. nodieri var. somalicus Guignot, 1952. These were synonymised in the world catalogue by Nilsson (2001). We are not convinced that they should be synonyms, but we do not formally elevate var. somalicus here as we have not seen enough continental material to evaluate character variations. We have studied female type specimens of both species and compared them with the new female referred to here as Copelatus sp. 1: it is similar to C. nodieri in that the first stria is present only in the posterior third. It differs from C. nodieri in that the elytra are largely black and lack a basal transverse testaceous band. It also differs in having a large lateral patch of anastomosing striolations not found in C. nodieri . Copelatus sp. 1 is similar in colour to C. nodieri var. somalicus and in having anastomosing striolation on the elytra. The striolation type differs markedly in expanse on the elytra, in impression, and in density. The striolations of the elytra reach the base in C. nodieri var. somalicus but starts first after the anterior third or fourth in Copelatus sp. 1. The striolation is formed by shorter, shallower, and denser strioles in Copelatus sp. 1 so that there are approx. ten parallel strioles medially across the width of the fourth interval on elytra. The strioles are longer and more deeply impressed in C. nodieri var. somalicus and only 5-6 strioles fit across the fourth interval medially on elytra. Finally, the posterolateral corners of the pronotum are striolated in C. nodieri var. somalicus but punctated in Copelatus sp. 1. Therefore, we conclude that Copelatus sp. 1 cannot be conspecific with either C. nodieri Régimbart or C. nodieri var. somalicus Guignot. It is more likely a new endemic species of Madagascar, the male of which should be sought for SE of Antsalova, Tsingy de Bemaraha NP, western Madagascar. We managed to sequence partial CO1 (311 bp) of this female which differed substantially from the three other species in the complex (K2P: 8.2-13.6%). DNA matching of the male, once discovered, would be straightforward.

Figures

Figure 2. Majority-rule consensus tree from Bayesian analysis of CO 1. Values next to nodes indicate posterior probabilities.

Figure 3. Result of the single-locus GMYC species delimitation using an ultrametric CO 1 genetree from BEAST. Black branches indicate interspecific divergences, red branches represent intraspecific coalescence events. Values above interspecific nodes indicate posterior probability from the Beast analysis under a strict clock model. The * indicates two nodes of further splitting from the GMYC analysis that is within the confidence interval of 2 Log likelihood units from the optimal solution.

Figure 8. Habitus, dorsal view. A Male: Copelatus marginipennis B Female: Copelatus mahajanga C Female: Copelatus sp. 1 (Bemaraha) D Male: Copelatus pulchellus.

Figure 11. Distribution maps of Copelatus species. A C. marginipennis (circle), C. baculiformis (square) B C. mahajanga (circle), C. sp. 2 (square) C C. pulchellus (circle), C. peridinus (square) D C. distinguendus (circle), C. sp. 1 (square).