Diastolinus shieli Hart and Ivie, 2016

Hart, Charles J. & Ivie, Michael A., 2016, A Revision of the Genus Diastolinus Mulsant and Rey (Coleoptera: Tenebrionidae), The Coleopterists Bulletin 70 (3), pp. 485-540 : 485-540

Diastolinus shieli Hart and Ivie , new species

( Figs. 20–23 , 106 )

Type Material. HOLOTYPE: Male. REDONDA BWI; 700 ft.; 17 IV 1958; J.F.G. Clarke / ex. dead agave/ WIBF 035570 ( NMNH) . PARATYPES (14 specimens): 1 female and 6 males sharing the same label data as the Holotype (from NMNH, WIBF 035571 – 035577 ). REDONDA, WEST INDIES:; 16°56.36′N, 62°20.75′W; 06AUG2005, 500– 900ft; I.A. Foley colr; under booby nests (4 females and 3 males, WIBF 035379, 035380, 035391, 035578 - 035581) .

Etymology. This species is named for the noted West Indian-born science fiction novelist Matthew Phipps Shiell (21 July 1865 – 17 February 1947), mostly known as M. P. Shiel, the first to claim the throne of the legendary Kingdom of Redonda. Note that his surname at birth had one “l” more than his pen name, and our epithet in his honor follows his use on his writings. Shiel assumed the title of King Felipe until, sans issue, he passed it to his appointed heir and literary executor, John Gawsworth. Though the control over the physical jurisdiction of the actual island is clear, the current succession of the title is disputed.

Diagnosis. This species can be distinguished from other species by the combination of the somewhat parallel-sided body, setose dorsal surface, matte black elytra with non-confluent strial punctures, two or fewer punctures evident on the sutural stria, small gular horns, evenly rounded lateral edges of the pronotum with the widest point appearing anterior of the hind angles, and male genitalia with weakly sinuate parameres that are subparallel with a bluntly rounded apex. This species closely resembles D. leewardensis , but can be distinguished by the denser and longer setae and abdominal ventrites 2–3 with shallow punctation on the anterior border. The status of the Redonda population as a species that differs from those of the islands surrounding it on three sides ( Fig. 106 ) is interesting, but apparently correct.

Description. Male. Length 9.0– 10.1 mm, width 3.9–4.2 mm. Body ( Fig. 20 ) black, except antennomeres reddish, apical 3 antennomeres testaceous; upper surface somewhat shiny, ventral surface somewhat shiny; oblong, almost parallelsided; widest at middle, moderately convex; with scattered yellowish setae.

Head ( Fig. 20 ) with epistoma broadly, evenly convex; punctures equal to diameter of ommatidium, covering dorsal surface, frons with shallowly, closely spaced punctures sometimes confluent, punctures deeper, more separate anterolaterally, separated by less than 1X puncture diameter; setae 2–3X length of puncture diameter. Labrum densely punctate. Antenna clavate. Dorsal and ventral portions of eye subequal in size and shape. Gular horns short.

Pronotum ( Fig. 20 ) widest at middle; apical margin evenly, broadly emarginate; apical corners rounded, lateral margin widened from apex in anterior 1/2, then sides narrowing to base; basal width subequal to width across humeri; basal margin bisinuate; dorsal surface broadly, evenly convex; all margins narrowly beaded, except obsolete at middle of anterior margin; densely punctate, puncture diameter subequal that of punctures on head, spaced 1–2X diameters of punctures on pronotal disc; yellowish setae typically 2–4X puncture diameter in length covering surface. Hypomeron rugulose, punctate shallowly. Prosternal process tongue-like, punctate.

Scutellum ( Fig. 20 ) small, subtriangular, about 2X wider than long. Elytron slightly broadening from base to widest point opposite abdominal ventrite 1, then evenly arcuate to apices; striae impressed; strial punctures deep, closely spaced, never confluent; intervals convex, punctation minute, even. Stria 7 ending in lateral stria slightly posterior to humeral angle.

Mesoventrite somewhat rugulose, punctate. Metaventrite short, punctate on anterior border behind mesocoxae.

Leg ( Fig. 20 ) surfaces densely setose and finely punctate. Protibia narrow, expanding gradually in distal 2/3; dorsolateral margin nearly straight; posteroventral surface with small, stout spines in apical 2/3; apex obliquely truncate, ringed by stout spines. Protarsus with tarsomeres 1–3 expanded, ventrally with golden, densely setose pads, tarsomere 2 widest, 1.5X width of tarsomere 4. Mesotarsus with tarsomeres 1–3 weakly expanded, ventrally with densely setose pads. Metatarsus narrow, about 1/2 as long as metatibia, without setose pads; 1 st tarsomere more than 2X length of 2 nd.

Abdominal ventrites ( Fig. 21 ) finely punctate and setose; ventrites 1–2 slightly concave medially; anterior border of ventrite 1, just behind hind coxae, with row of heavy punctures extending onto intercoxal process; ventrites 2 and 3 laterally with row of punctures on anterior edge, indistinct on medial concavity, punctures relatively shallow compared to punctures on ventrite 1, longitudinally rugulose areas posterior of punctures; ventrite 3 flattened medially; ventrite 5 depressed medially, posterior margin evenly rounded. Aedeagus ( Figs. 22, 23 ) with basal piece and parameres strongly arched, about 1/2 elytral length; parameres parallel in basal 2/3, narrowed in apical 1/3, tips bluntly rounded; parameres with weakly sinuate lateral margin, slightly upturned tips in lateral view.

Female. Length 9.5–10.1 mm, width 4.0– 4.5 mm. Similar to male except body typically larger, more robust than male. Pro- and mesotarsi not expanded. Abdominal ventrites 1–3 slightly convex medially; ventrite 5 slightly convex.

Biology. Adults have been collected in booby nests on the ground and from dead agave. Specimens have been found at elevations ranging 213– 274 m above sea level.

Distribution. Redonda * (NMNH, WIBF) ( Fig.106 ).

Discussion. The existence of this species is perhaps the most surprising finding of this study. Redonda is the apex of an extinct volcano between Nevis and Montserrat, rising steeply from the sea with no beach or landing. The entire island is cinder, with no sand areas like those where most Diastolinus are found. Redonda rises to a peak at 296 m and was never connected to any other island. The range of D. leewardensis surrounds it on three sides ( Fig. 106 ) and appears to be the sister-species.

Figures

Figs. 16–23. Diastolinus leewardensis, holotype: 16) Dorsal habitus; 17) Abdominal ventrites; 18) Aedeagus, dorsal view; 19) Aedeagus, lateral view. Diastolinus shieli, paratype: 20) Dorsal habitus; 21) Abdominal ventrites; 22) Aedeagus, dorsal view; 23) Aedeagus, lateral view.

Fig. 106. Map of the distributions of Diastolinus species in the Lesser Antilles.