Diastolinus tibidens ( Quensel, 1806 )

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 tibidens ( Quensel, 1806)

( Figs. 61–67 , 104 )

Blaps tibidens Quensel 1806: 147 (type locality: Virgin Islands).

Sellio tibidens ; Mulsant and Rey 1859: 109, 1860: 173 (Antilles); Leng and Mutchler 1914: 460 (Antilles); Wolcott 1936: 234 ( Puerto Rico); Gebien 1938: 407 [444] (Antilles); Blackwelder 1945: 525 ( Puerto Rico?); Wolcott 1951: 326 ( Puerto Rico); Marcuzzi 1957: 129 (St. Thomas, Puerto Rico), 1962: 31 (in part, St. Thomas records only), 1984: 82 (in part, Puerto Rico, St. Thomas records only); Garrido 2003: 27 ( Puerto Rico), 2004b: 119 (in part, St. Thomas, Puerto Rico records only); Valentine and Ivie 2005: 279 (Guana).

Sellio probably tibidens Wolcott 1923: 96 ( Puerto Rico).

Sellio tibiensis ; Iwan 2004: 741, 749 (lapsus calami).

Type Material. The holotype ( NHRS- JLKB000041162 ) is mistakenly labeled “Africa,” here corrected to St. Thomas ( Figs. 61, 62 ). The specimen was photographed by Johannes Bergsten, NHRS, and the image was made available by NHRS under Creative Commons Attribution 4.0 International Public License (CC-BY 4.0).

Other Material Examined. See Appendix 1.

Diagnosis. This species can be distinguished from other species by the combination of the base of the elytra, including humeri, much narrower than pronotum, elytra costate with large strial punctation, scutellum large, distinct, and triangular, and body less than 7.5 mm in length. Males of this species are the only ones in the genus in which the profemur has a small basal spine on the posteroventral surface that nearly meets the large protibial spine when the leg is retracted.

Note. This species is widespread throughout Puerto Rico and the Virgin Islands, but there seems to be little morphological difference between island populations.

Redescription. Male. Length 6.3–7.3 mm, width 2.4–3.0 mm. Body ( Fig. 63 ) black, except last 3 antennomeres testaceous; somewhat dull on upper surface, somewhat shiny on ventral surface; oblong; widest on pronotum, moderately convex; scattered white to golden setae typically short.

Head ( Figs. 61, 63 ) with epistoma evenly convex; punctures greater than diameter of ommatidium, covering dorsal surface, evenly spaced, separated by 1 puncture diameter posteriorly, separated by less than 1 puncture diameter anteriorly; setae 2–3X length of puncture diameters. Labrum densely punctate. Antenna clavate. Dorsal and ventral portions of eye roughly equal in size and shape. Gular horns short.

Pronotum ( Fig. 63 ) widest at anterior 1/3; apical margin evenly, broadly emarginate; apical corners rounded, lateral margin widened from apex in anterior 1/3, then sides narrowing slightly to base; base wider than 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 equal to puncture diameters on head, spaced 2–3X puncture diameter pronotal disc; setae 4X puncture diameter in length. Hypomeron feebly rugulose, shallowly and sparsely punctate. Prosternal process somewhat convex, tongue-like, punctate.

Scutellum ( Fig. 63 ) triangular, about 2X wider than long. Elytra constricted in anterior 1/3. Elytron gradually broadening from base to widest point opposite abdominal ventrite 2, then evenly arcuate to apices; striae heavily impressed; strial punctures deep and not confluent; intervals convex, punctation minute, even. Stria 7 ending in lateral stria posterior to humeral angle.

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

Leg ( Figs. 61, 63 ) surfaces setose and finely punctate. Femora expanded; profemur especially inflated, anterodorsal margin arcuate; small basal spine on posteroventral surface, nearly meeting large protibial spine when leg retracted ( Fig. 64 ). Protibia narrow basally, then suddenly expanded in apical third into large, triangular spine on posterventral surface ( Figs. 63, 64 ); stout spines after major spine; apex obliquely truncate, ringed by stout spines. Protarsus with tarsomeres 1– 3 expanded, ventrally with golden, densely setose pads, tarsomere 2 widest, more than 2X width of tarsomere 4. Mesotarsus with tarsomeres 1– 3 weakly expanded, ventrally with densely setose pads. Metatarsus narrow, about 2/3 as long as metatibia, without setose pads; 1 st tarsomere more than 2X length of 2 nd.

Abdominal ventrites ( Fig. 65 ) shallowly 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, longitudinally rugulose areas posterior of punctures; ventrites 2–4 with row of heavy punctures on anterior edge, longitudinally rugulose areas posterior of punctures; ventrite 5 flattened medially, posterior margin evenly rounded. Aedeagus ( Figs. 66, 67 ) with basal piece and parameres strongly arched, more than 2/3 elytral length; parameres subparallel for basal 1/2, then widened broadly apically, then broadly rounded to apex; expanded area slightly concave; parameres with sinuate lateral margin, undulate with slightly upturned tips in lateral view.

Female. Length 6.5–7.4 mm, width 2.5– 3.1 mm. Similar to male except pro- and mesotarsi not expanded. Abdominal ventrites 1–2 slightly convex medially; ventrite 5 slightly convex.

Biology. Adults have been collected in leaf litter, under trash, under bark, on the ground at night, and at light, as well as in FIT and Berlese samples. Specimens have been found at elevations ranging 0–104 m above sea level.

Distribution. Puerto Rico, Culebra * (AMNH), St. Thomas, St. John* (WIBF), Jost van Dyke (WIBF), Tortola * (WIBF), Guana (TOR), Prickly Pear Is.* (VG, BMNH, WIBF), St. Croix* (AMNH, WIBF), Buck Is.* (STX, WIBF) ( Fig. 104 ).

Diastolinus tibidens (Quensel)

VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; on Ridge Trail; 25 AUG 1995, M.A.; Ivie & M. Dunnington (47 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; 24 AUG 1995, at light; M.A. Ivie &; Z.M. Hillis colrs (10 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; Diedrick’ s shack; 06 SEP 1996; A. Poponi. Berlese (2 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; 17 FEB 1997; A. Poponi colr; flight intercept trap (3 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; North side trail; 23 AUG 1996; A. C. Poponi, F.I.T. (1 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; northside hike trail; 09 AUG 1996, FIT; A. C. Poponi colr (1 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; 28 NOV 1995, F.I.T.; Z.M. Hillis colr. (1 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; 28 NOV 1995; Z.M. Hillis colr. (2 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; 28 NOV-09 FEB 1996; Z.M. Hillis colr; flight intercept trap (3 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; Northside, trail; 09 AUG 1996; Z.M. Hillis, F.I.T. (6 WIBF). VIRGIN IS: Buck Is.; B.I. Reef Nat. Mon; trail at 340′; 25 AUG 1995, uv light; Berlese under Bursera (1 WIBF). VIRGIN IS: Buck Is.; Buck Is. Reef N.M.; 08NOV1994 – 19JAN1995; flight intercept#15; 340ft., Z.M. Hillis (1 WIBF). VIRGIN IS: Buck Is.; Buck Is. Reef N.M.; 19JAN-30 MAR 1995; flight intercept#15; 340ft., Z.M. Hillis (3 WIBF). VIRGIN IS: Buck Is.; Buck Is. Reef N.M.; 30 MAR-29 JUNE 1995; flight intercept#15; 340ft., Z.M. Hillis (5 WIBF). VIRGIN IS: Buck Is.; Buck Is. Reef N.M.; SEP-OCT 1993; flight intercept#14; 140ft., Z.M. Hillis (1 WIBF). VIRGIN IS: Buck Is.; Buck Is. Reef N.M.; 08–29 JAN 1993; flight intercept#15; 340ft., Z. Hillis (2 WIBF). VIRGIN IS: Buck Is.; Buck Is. Reef N.M.; 01–31MAR 1993; flight intercept#15; 340ft., Z. Hillis (2 WIBF). VIRGIN IS: Buck Is.; Buck Is. Reef N.M.; 08JAN 1993. general; coll. VIBFP colrs (1 WIBF). St. Croix; V.I., W.I.; H.A.Beatty (1 WIBF). St. Croix VI; HABeatty (2 WIBF). VIRGIN IS: St. Croix; Christiansted; Spring Gut, 15FEB; 1983. J.A. Yntema; under trash (1 WIBF). VIRGIN IS: St. Croix; Estate Cotton Garden; S.E.T.I. Station; 12JAN1993. R.S.Miller; night collecting (9 WIBF). VIRGIN IS: St. Croix; Estate Cotton Garden; S.E.T.I. Station; 12JAN1993. at night; D.S. Sikes colr (8 WIBF). VIRGIN IS: St. Croix; Estate Cotton Garden; nr. S.E.T.I. Station; 11JAN1993. D.S. Sikes; grass/xeric litter (1 WIBF). VIRGIN IS: St. Croix; Est. Jerusalem &; Figtree Hill, MARCH; 1993. B.Wilhelm (1 WIBF). VIRGIN IS: St. Croix; Est. Cotton Garden; nr. Sugarloaf Hill; 11JAN1993, D.S. Sikes (1 WIBF). VIRGIN IS: St. Croix; Est. A Piece of Land; East End, 09JAN1993; VIBFP colrs (3 WIBF). F5D18; St. Croix, V.I.; III.1.1925 (2 AMNH). VIRGIN IS: St. Thomas; Estate Nazareth. Sea; Horse-Secret Harbor; 02JAN1993. K.B. Reeves; & D.H.Chadwick colrs (4 WIBF). VIRGIN IS: St. Thomas; Estate Nazareth. Sea; Horse Cottages; 01–04JAN 1993. 120ft; VIBFP colrs (2 WIBF). VIRGIN IS: St. Thomas; Est. Nazareth. 40ft; 01JAN1993 – 06JUL1994; VIBFP colrs; flight intercept#9 (2 WIBF). VIRGIN IS: St. Thomas; Est. Nazareth. 40ft; 06JULY-26JULY1994; Ivie, Becker & Bucklin; flight intercept#9 (1 WIBF). Charlotte Amilia; St. Thomas, D.W.I.; June 2, 1911 (1 AMNH). F.5134c; St. Thomas, V.I.; III.12.1925 (1 AMNH). F5D11; St. Thomas, V.I.; II.25.1925 (2 AMNH). F5029; St. Thomas, V.I.; II.11.1925 (1 AMNH). St. Thomas / Sellio tibidens ; Quens. (1 NHMB). St. Thomas/ tibidens ; Quens.; det. Marcuzzi (1 HNHM). St. Thomas/ coll R. Oberthür; ex coll Deyrolle/ Sellio ; tibidens Sch / tibidens ; det. Marcuzzi (1 HNHM). Ins:Amer; Smidt; Mus: Sc&J.L. (3 ZMUC). St. Thomas/ Coll Rosenberg (1 ZMUC). M. Cameron; Journal; W. I. 1053 / W. INDIES; Prickly Pear Is.; 9August1908; Dr. M. Cameron; B.M. 1936-555 (1 WIBF). BRITISH VIRGIN IS; Jost Van Dyke; White Bay; 23–24 JULY 1994; M. A. Ivie colr. (1 WIBF). BRITISH VIRGIN IS; Guana Island; Hotel to Palm Ghut; 20 OCT 2002; M. A. Ivie, at night (1 WIBF). BR.VIRGIN IS: Tortola; East End. Queen; Elizabeth Bridge; 23OCT1992. under bark; M. A. Ivie colr. (2 WIBF). VIRGIN IS: St. John; Estate Concordia; Ramshead Pt. Trail; 18– 19JULY1994, leaf; litter, M.S. Becker (9 WIBF). VIRGIN IS: St. John; Est. Caneel Bay; CaneelBay to LindPt; 0–75m, 02JAN1993; Ivie, Miller & Sikes (1 WIBF). VIRGIN IS: St. John; Cruz to Lind Pt; 02JAN1993. at night; Ivie, Miller & Sikes (4 WIBF). VIRGIN IS: St. John; Rams Head, nr. Point; 07FEB1986; W.B. Muchmore colr (2 WIBF). Lameshur Bay; St. John, Virgin I.; Jan.4,1966; coll.R.T.Bell –A (1 WIBF). CulebraVI; Mch 4. 06; WheelerColl (1 AMNH). CulebraVI; Mch 5. 06; WheelerColl (5 AMNH). Aguirre,P.R.; Acc#282-1923/ G.N. Wolcott ; Coll (2 AMNH). Ponce, P.R.; July20–22,’14 (2 AMNH). Guanica; I.12.15. P.R.(1 AMNH). Coamo Sprs.P.R.; June 5–7, 1915 (1 AMNH).

Figures

Figs. 61–67. Diastolinus tibidens, holotype. 61) Head and pronotum (Photograph by Johannes Bergsten, NHRS; made available by NHRS under Creative Commons Attribution 4.0 International Public License CC-BY 4.0); 62) Labels; 63) Dorsal habitus; 64) Fore leg; 65) Abdominal ventrites; 66) Aedeagus, dorsal view; 67) Aedeagus, lateral view.

Fig. 104. Map of the distributions of the “sellio” species-group of Diastolinus species on Puerto Rico and Virgin Islands. Symbols on Puerto Rico represent collecting localities, and symbols on the Virgin Islands represent island distributions, not all collection events.