Diastolinus leewardensis 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 leewardensis Hart and Ivie , new species

( Figs. 16–19 , 106 )

Diastolinus puncticollis: Marcuzzi 1957: 128 (in part, Saba, St. Eustatius, St. Kitts, Nevis records only), 1962: 26 (in part, Saba, St. Eustatius, St. Kitts, Nevis records only), 1977: 22 (in part, Barbuda, Nevis, St. Kitts, St. Eustatius, Saba records only), 1983: 244 (male genitalia, Saba, Antigua), 1984: 78 (in part, Nevis, St. Kitts, St. Eustatius, Saba, Antigua records only), 1987: 96 (female genitalia, St. Kitts); Ivie et al. 2008: 253 (Montserrat); Peck 2011a: 33 (in part, ∼ Antigua, Barbuda, Saba, St. Eustatius, St. Kitts, Montserrat, Nevis records only), 2016: 160 (in part, ∼ Antigua, Barbuda, Saba, St. Eustatius, St. Kitts, Montserrat, Nevis records only); Peck et al. 2014: 84 (in part, ∼ Antigua, Barbuda, Saba, St. Eustatius, St. Kitts, Montserrat, Nevis records only).

Diastolinus sallei ; Marcuzzi 1957: 128 (in part, St. Kitts, Barbuda, Antigua records only), 1962: 25 (in part, Antigua, Barbuda records only), 1977: 22 (in part, Antigua, Barbuda, Saba records only), 1984: 78 (in part, Antigua, Barbuda records only); Peck 2006: 189 (in part, Antigua, Barbuda records only), 2011a: 33 (in part, Antigua, Barbuda, Saba records only), 2016: 160 (in part, Antigua, Barbuda, Saba records only); Peck et al. 2014: 84 (in part, Antigua, Barbuda, Saba records only); Soldati and Touroult 2014: 99 (in part, Antigua, Barbuda, Saba records only).

Diastolinus costipennis ; Marcuzzi 1957: 128 (in part, St. Kitts records only), 1962: 27 (in part, St. Kitts records only), 1984: 77 (in part St. Kitts records only); Marcuzzi and D’ Aguilar 1971: 80 (in part, St. Kitts records only); Peck 2011a: 33 (in part, St. Kitts records only), 2011b: 29 (in part, St. Kitts records only), 2016: 159 (in part, St. Kitts records only); Soldati and Touroult 2014: 99 (in part, St. Kitts records only).

Sellio coarctatus Marcuzzi 1962: 31 (in part, St. Kitts records only), 1984: 82 (in part, St. Kitts records only); Garrido 2004b: 119 (in part, St. Kitts records only); Peck 2011a: 33 (in part, St. Kitts records only), 2016: 160 (in part, St. Kitts records only).

Diastolinus clavatus ; Marcuzzi 1977: 13 (in part, Nevis records only); Peck 2011a: 33 (in part, Nevis records only), 2016: 159 (in part, Nevis records only).

Type Material. HOLOTYPE: Male. SABA: NETH.ANT.: Dancing; Place Tr. Trailhead el. 328m; 17.62452°N, 63.23713°W ± 23m; dry forest leaf litter, Berlese; 13MAR2008 D.S. Sikes / WIBF 034011 (from WIBF, deposited in NMNH). PARATYPES (36 specimens): SABA: NETH.ANT.: Dancing; Place Tr. Trailhead el. 401m; 17.62452°N, 63.23713°W ± 23m; dry forest, uv light/hand coll.; 13MAR2008 D.S. Sikes (7 females and 11 males, WIBF 034510 - 034527 ). SABA: NETH.ANT.: Dancing ; Place Tr. Trailhead el. 291m; 17.6245°N, 63.2371°W ± 9m; roadside, headlamp 2100-2200; 13MAR2008 J.A. Slowik (1 female, WIBF 034757 ). SABA: NETH.ANT.: Mt. Scenery ; Tr. Trailhead el. 339-350m; 17.62873°N, 63.23348°W; ± 10.5m wet forest, night coll. Uv; 12MAR2008 D.S. Sikes (1 male, WIBF 034101 ). SABA: NETH.ANT.:; Windwardside , Scout’ s Place ; Hotel el. 405m, 17.62789°N; 63.23143°W ± 20m at lights; 9MAR 2008 D.S. Sikes (3 females and 2 males, WIBF 034198 – 034201 , 034210 ). SABA: NETH.ANT.: Fort Bay ; Beach , Giles Quarter Trail ; 17.6151°N, 63.2454°W ± 9m; rocky beach, flip rocks 830-910; 12MAR2008 J.A. Slowik (1 female, WIBF 034754 ). SABA: NETH.ANT.: Jan’ s House ; Boobie Hill el. 359m, 17.6232°N; 63.2267°W ± 6m shrubs, 10; pitfalls, 13-15MAR2008 J.A.; Slowik (1 male, WIBF 034761 ). SABA: NETH.ANTL.; Near Boobie Hill , 401m; 17.62318°N, 63.22675°W; 13MAR-01APR2008, D. Sikes; J. Slowik, FIT w/ pitfall (1 female, WIBF 057789 ). SABA: NETH. ANTL.; Near Boobie Hill , 401m; 17.62318°N, 63.22675°W; 01APR-01MAY2008, D. Sikes; J. Slowik, FIT w/ pitfall (1 male, WIBF 057209 ). SABA: NETH.ANTL.; Dancing Place Trail , 346m; 17.62551°N, 63.23464°W; 23MAY2008 M.A. Ivie; beating dead trees (1 female, WIBF 057071 ). WEST INDIES: SABA; Windwardside ; 25 March 1986; R.S. Miller colr. (2 females, WIBF 035565 – 035566 ). WEST INDIES: SABA; Windwardside ; 19 March 1986; R.S. Miller colr. (1 male, WIBF 035567 ). WEST INDIES: SABA; SW. Windwardside; 21 March 1986; R.S. Miller colr.; xeric scrub (1 female, WIBF 035568 ). WEST INDIES: SABA; Gut W. Hells Gate; 24 March 1986; mesic forest; R.S. Miller colr. (1 male, WIBF 035321 ). SABA, NETH.ANT.; Mountain Road; 24 OCT 2010; M. Gillet colr; SB0339 (1 female, WIBF 035569 ).

Other Material Examined. See Appendix 1.

Etymology. This species is named for its broad distribution throughout the Leeward Islands of the Lesser Antilles.

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 hind angles, and male genitalia with weakly sinuate parameres that are subparallel with a bluntly rounded apex. This species closely resembles D. shieli , but can be distinguished by the less dense and shorter setae and abdominal ventrites 2–3 with larger, deeper punctation on the anterior border.

Note. The elytral striae are somewhat less impressed and the strial punctures shallower in Barbuda and Antigua specimens.

Description. Male. Length 7.5–9.1 mm, width 3.1–4.0 mm. Body ( Fig. 16 ) black, except last 3 antennomeres testaceous; upper surface dull, ventral surface somewhat shiny; oblong, almost parallelsided; widest at middle, moderately convex; scattered pale, short setae.

Head ( Fig. 16 ) with epistoma evenly convex; punctures equal to diameter of ommatidium, covering dorsal surface, evenly spaced, separated by 1X puncture diameter posteriorly, separated by less than 1X puncture diameter anteriorly; setae 2X longer than puncture diameter. Labrum densely punctate. Antenna clavate. Dorsal and ventral portions of eye subequal in size and shape. Gular horns short.

Pronotum ( Fig. 16 ) 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; punctate, puncture diameter subequal to that of punctures on head, spaced 1X diameter of punctures on pronotal disc; fine pale setae typically 2–4X puncture diameter in length covering surface. Hypomeron feebly rugulose, punctate shallowly. Prosternal process tongue-like, punctate.

Scutellum ( Fig. 16 ) 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, 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 surfaces 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 2X length of 2 nd.

Abdominal ventrites ( Fig. 17 ) finely punctate; 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 heavy punctures on anterior edge, indistinct on medial concavity; ventrite 5 flattened medially, posterior margin evenly rounded. Aedeagus ( Figs. 18, 19 ) with basal piece and parameres strongly arched, less than 1/2 elytral length; parameres subparallel 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 8.0–10.0 mm, width 3.6– 4.4 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 dry and moist forest, at night with UV lights, beating dead trees, and under bark. They have been collected at night on the ground as well as from the pitfall portion of a FIT and Berlese samples. Specimens have been found at elevations ranging 0–400 m above sea level.

Distribution. Antigua, Barbuda, Saba, St. Eustatius, St. Kitts, Nevis, Montserrat ( Fig. 106 ).

Discussion. Echoing the situation for D. chalumeaui above, this species also has an extensive literature history based entirely on misidentifications. None of the five species whose names have been used for populations belonging to this species actually occur on the Leeward Islands. Although the islands where this species occurs were not a single Pleistocene bank, they were all very close during the eusatastic minima. Antigua and Barbuda were connected on the Barbuda- Antigua Shelf, as were adjacent St. Eustatius, St. Kitts, and Nevis on the Statia Shelf. Saba was very close to both these large islands. Only Montserrat is a geographic outlier, as it would have been expected to have D. chalumeui , rather than D. leewardensis . The existence of the singleisland endemic D. shieli on Redonda, located between Montserrat and Nevis and in sight of both, is also a surprise. Since Redonda stands between the D. leewardensis populations on Nevis and Montserrat, it would be expected to either have the Nevis-Montserrat species, share one with Montserrat, or predict an endemic on Montserrat. Nature is most interesting when it provides these conundrums.

Diastolinus leewardensis Hart and Ivie

WEST INDIES: SABA; SW. Windwardside; 21 March 1986; R.S. Miller colr.; xeric scrub (2 OSUC). WEST INDIES: SABA; Windwardside to; Ft. Bay Gut E. Bottom; 21 March 1986; R.S. Miller colr. (1 OSUC). WEST INDIES: SABA; Windwardside; 25 March 1986; R.S. Miller colr. (1 OSUC). ST. EUSTATIUS: 234m; Quill Trail The Bench; 17.47461°N, 62.96896°W; 27MAY 2008 in logs; and beating, M.A. Ivie (1 WIBF). ST. EUSTATIUS: Venus Bay; Boven Sec Natl Park 0–6m; 17.51544°N, 62.98960°W; 26MAY2008 beach/beating; M.A. Ivie & N. Esteban (1 WIBF). EUSTATIUS, Quill; Glass Bottle, 12.VII; 1949, No.471/ Diastolinus ; puncticollis M&R; det. Marcuzzi (1 HNHM). WestIndies:; Nevis; 24-26.ii.1931; Lt.Com.R.H.S.Roger.; B.M.1931-181 (1 BMNH). BARBUDA BWI; Derby Cave; 26 IV 1958; J.F.G. Clarke (44 NMNH). BARBUDA BWI; nr. Martello; Tower 7-IV’56; J.F.G. Clarke (3 NMNH). W.Indies 1959; Barbuda 23 IV; papaya tree (3 NMNH). Barbuda; West Indies/ 22/ Diastolinus ; puncticollis M&R; det. Marcuzzi (1 HNHM). Barbuda; West Indies/ Diastolinus ; perforatus Sahlb. ; det. Marcuzzi (1 HNHM). Antigua; W. Indies; June 26-18; L. Stoner (10 AMNH). Antigua; W. Indies; June 24–18; L. Stoner (12 AMNH). Antigua; W. Indies; June 24; L. Stoner (7 AMNH). Antigua; W. Indies; June; L. Stoner (1 AMNH). Antigua; W. Indies; June 1918; L. Stoner (2 AMNH). Antigua; W. Indies/ June 20; L. Stoner (3 AMNH). Antigua; W. Indies/ June 21; L. Stoner (1 AMNH). Antigua; W. Indies; July 1–18; L. Stoner (5 AMNH). Antigua; BWI; 28-VIII-36/ Sta.282; Chapin and; Blackwelder (8 NMNH). Antigua; W.9.; MarcsRall./ Diastolinus sp. ; near puncticollis Muls ; J.B./ G.C. Champion Coll.; B.M.1927-409 (1 BMNH). Antigua / ∼ F.Chev./ F.Bates; 81-19/ Diastolinus ; sallei M&R (1 BMNH) . BWI: ANTIGUA: St. Mary; Par., Darkwood Beach; 21 Jan 1986 / u.rock; leg. D.M.Field; & W.Setter/ Opatrinus ; clathratus (Fab.) ; det. C.A.Triplehorn’00 (1 FMNH). ANTIGUA: SE of; English Harbor Town; 21 NOV 1999; M.A. Ivie. und.rocks (2 WIBF). MONTSERRAT: Woodlands Ghaut, 43m; 16°45.99’N, 69°13.34′W; 03JAN2002, M.A. Ivie; beating & under bark (2 WIBF).

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.