Sarmydus nicobarensis, Majumder & Drumont & Chandra & Dubey, 2019

Majumder, Amitava, Drumont, Alain, Chandra, Kailash & Dubey, Anil Kumar, 2019, A new species of Sarmydus Pascoe, 1867 (Cerambycidae: Prioninae: Anacolini) from Nicobar Island, India, Zootaxa 4674 (2), pp. 235-242 : 236-241

Sarmydus nicobarensis sp. nov. Majumder, Drumont & Chandra

( Figs. 1 , 2 and 4 )

Type material: HOLOTYPE: ♂, ‘ India: Nicobar Island / Great Nicobar / Laxmi Nagar / 6°55’33.7’’N 93°53’58.4’’E / 18.XI.2018 / K.C Gopi Coll. // HOLOTYPE / Sarmydus nicobarensis sp. nov. / des. Majumder, Drumont & Chandra, 2019’ (red label) (ZSI). PARATYPES (in addition to white locality label, with a second pink label: PARATYPE / Sarmydus nicobarensis sp. nov. / des. Majumder , Drumont & Chandra, 2019): 2 ♂, India: Nicobar Island / Great Nicobar / East West Road / 18.XI.2018 / 6°59’28.1’’N 93°52’18.6’’E / A.K Dubey Coll. (ZSI) ; 1 ♂, India: Nicobar Island / Great Nicobar / Laxmi Nagar / 18.XI.2018 / 6°55’33.7’’N 93°53’58.4’’E / K.C Gopi Coll. (ZSI) ; 1 ♂, India: Nicobar Island / Great Nicobar / Shastri Nagar / 14.XI.2018 / 6°48’29.9’’N 93°53’08.8’’E / K.C Gopi Coll. (ZSI) ; 2 ♂, India: Nicobar Island / Great Nicobar / Galathea end road/ 12.XI.2018 / 6°49’01.6’’N 93°52’30.3’’E / K.C Gopi coll. (ZSI) . ALLOTYPE (in addition to white locality label, with a second red label: ALLOTYPE / Sarmydus nicobarensis sp. nov. / des. Majumder, Drumont & Chandra, 2019), 1 ♀, India: Nicobar Island / Camorta Island, (MNHN) .

Description: Holotype, ♂: body length, 20 mm; width, 7 mm; elytra length, 13 mm; pronotal length, 2 mm; pronotal width, 5 mm; antennal length, 20 mm.

Male: Body not glossy, mostly dark blackish brown; legs, pronotum, antennal segments dark brown; elytra dark blackish brown, very little paler at apex; scutellum dark coloured; joints of femur and tibia darker in colour.

Head: Not pubescent with deep punctures, almost covered with eyes and antennal tubercles; mandibles deeply punctate; frons densely punctate, very narrow, distinctly transverse, with a few golden setae anteriorly. Vertex densely punctate, narrower between eyes and antennal tubercles. Eyes large, undivided, coarsely facetted, facets both brown and black; gena distinctly short; gulamentum depressed, with small wart.

Antennae: Eleven-segmented, flat, slightly shorter than body, antennomeres III-XI deeply, longitudinally striated, more so on outer surface; apex of inner margin of antennomeres III-X acute, with spine-shaped appearance; scape and pedicel slightly darker, shining, with deep punctures and fine golden setae; II short, base narrowed, slightly widened toward apex; III longest, somewhat shining at base of inner margin; segments IV-X very finely punctured, segments became gradually shorter in size; segment XI longer than X.

Pronotum: Middle of disk surface matt, slightly depressed, wrinkled; sides somewhat tumid; granulated laterally and anteriorly, background of surface between granules covered by fine punctation. Martins with dense, long golden setae; middle of lateral margin with moderate well-developed spine; just beneath lateral margin and spine there is rounded depression, deeply punctured centrally. Antero lateral margin of pronotum wider and almost round- ed than lateral part behind spine; posterolateral margins convergent. Posterior margin of pronotum strongly sinuous; anterior margin weekly curved.

Elytra: Matt, parallel-sided, not pubescent, apex rounded. Lateral margin fine, with short setae. Surface evenly, moderately punctured, punctures deep at basal one-fourth, becoming finer towards apex. Each elytron with four primary costae: innermost from near base to posterior fifth, nearly straight, oblique towards inner margin, connected with second one apically; third one small, starting after middle of elytron, extending to apex level of innermost costa, and very palely connected with second, sometimes disrupted; fourth and second almost reaching elytral apex, connected between them apically. With two additional small costae started from rounded apex of second and touching sutural margin. Cross vein are not prominent. Scutellum lingulate, coarsely granulated.

Venter: Prosternal process elongated, curved and rounded at tip, with small tubercles throughout. Mesosternal process somewhat tongue-shaped, depressed at middle, with small tubercle covered with long, sparse setae. Metasternum, rough, slightly shining, covered with long golden setae. Abdomen faintly covered with golden setae, which are smaller in size than those on metasternum, not punctured. Legs densely covered with golden setae; femur flattened, slightly channeled underneath; tibia with two spur; profemur and tibia equal in length; mesotibia slightly longer than mesofemur, and hind tibia much longer than hind femur.

Male genitalia: Median struts 1.5 times longer than median lobe; medial part slightly longer than tegmen; median struts distant from each other; apex of median lobe projected and pointed centrally. Ring portion of tegmen converging throughout, pointed at tip. Lobes of parameres long, much closer and covered with sparse, long setae. Internal sac tube like with small plate-shaped wrinkle structure.

Female: length: body measured from clypeus to elytral apex: 26 mm; elytral length, 18 mm; pronotal length, 3.5 mm; width measured at humeri, 8.5 mm. Shape of female body is rather similar to males. Colour of female looks paler because specimen is old and faded.

Antennae: reaching posterior fifth of body. Antennal segments more elongated and thin; anterior half of segment III covered with punctures and longitudinal carinae, margin with short erected yellow setae.

Pronotum: lateral spine located at middle of its length less defined and not so much sharp.

Legs: thin with same pilosity as in males but with setae shorter and sparser.

Differential diagnosis: The males from Nicobar Island were different from the other two known Indian species, S. antennatus and S. subcoriaceus in having dull body colour and completely dark brown antennae against glossy body colour and antenna brown to yellow in subsequent segments in both the species. These males showed antennal resemblance with S. paukstadtorum , which was described from Indonesia (northern Sumatra), but differed from it significantly. Superficially, males of the new species resemble those of S. paukstadtorum , but differ in having dull blackish-brown body; pronotum longer, margin not wide and spines are relevantly small; elytra parallel-sided and without abundant transverse veins; antennal segment III longer (ratio length / width: around 3.1). Males of S. paukstadtorum have shining and dark brown body; wide pronotum, more angulated, armed with large and broader spines which is distinctly differentiable; elytral sides gradually and slightly convergent; elytra with prominent small interconnected coarse veins on punctures; and antennal segment III shorter in length (ratio length / width: around 2.5). The new species is different from the species recorded from mainland India, but closer to Indonesian species. This may indicate their evolutionary assemblage coupled with geographical isolation; however, genetic studies may reveal their relationship.

Etymology: The name nicobarensis refers to the collection locality Nicobar group of islands.

Distribution: India: Nicobar group of Islands: Great Nicobar and Camorta.

Discussion

In his “Fauna of British India,” Gahan (1906) mentioned the distribution of S. antennatus from Andaman and Nicobar Island, but the specific location of Nicobar was not mentioned. We are not aware of any subsequent work on this genus from India or these islands. We found individuals of the new species only from the Nicobar Islands. We did not find any specimen of Sarmydus in collections of the Zoological Survey of India from Nicobar. Probably, citations of S. antennatus in Nicobar Islands ( Mukhopadhyay & Biswas, 2000; Mukhopadhyay & Halder, 2004; Mitra et al., 2014, 2016, 2017) followed Gahan (1906) as those citations never mentioned any locality data. Therefore, it is not certain that S. antennatus occurs in Nicobar Islands. We believe the new species described herein is likely endemic to Nicobar Islands.

Figures

FIGURE 1. Sarmydus nicobarensis sp. nov. Holotype, male: A, dorsal; B, ventral; D, elytra; E, pronotum; F, head and mandible; G, antennal segments. C, allotype female, dorsal.

FIGURE 2. Sarmydus nicobarensis sp. nov. Holotype, male, genitalia: A, Dorsal; B, Ventral; C, Lateral; D, Apex of median lobe and lateral lobes.

FIGURE 4. Sarmydus nicobarensis sp. nov. A: Map of collection localities; B: Photograph of live specimen; C: Habitat of Nicobar.