A Revision of the GenusDiastolinusMulsant and Rey (Coleoptera: Tenebrionidae)
Author
Hart, Charles J.
Author
Ivie, Michael A.
text
The Coleopterists Bulletin
2016
2016-09-30
70
3
485
540
http://dx.doi.org/10.1649/0010-065x-70.3.485
journal article
10.1649/0010-065X-70.3.485
6954310
Diastolinus
Mulsant and Rey, 1859
Diastolinus
Mulsant and Rey 1859: 74
,
1860: 138
.
Type species:
Blaps clathrata
Fabricius, 1792
by subsequent designation of
Lucas 1920: 236
.
Gebien 1938: 294
[413];
Blackwelder 1945: 524
;
Marcuzzi 1986: 179
,
1989: 355
,
1998: 153
;
Iwan 2004: 739
.
Sellio
Mulsant and Rey 1859: 105
,
1860: 169
.
Type
species:
Blaps tibidens
Quensel, 1806
by subsequent designation of
Gebien 1938: 407
[444].
Blackwelder 1945: 525
;
Iwan 2004: 739
.
Ctesicles
Champion 1896: 7
.
Type
species:
Ctesicles insularis
Champion, 1896
by subsequent designation of
Lucas (1920)
.
Gebien 1938: 401
[438];
Blackwelder 1945: 524
.
Diagnosis.
As redefined by
Ivie and Hart (2016)
, this genus can be recognized and separated from other “blapstinoids” by a combination of the elytra fused together in fully developed specimens; the elytral striae are typically strongly punctate and impressed; the elytra have the anterior end of stria 8 displaced laterad, ending at the lateral stria, cut off from the base of the elytra by stria 7, which also curves laterad and ends either at the humeral angle or on the lateral stria (
Figs. 2
,
27
,
88
); the metathoracic wings are reduced or absent; the metaventrite is very short, usually shorter than the mesocoxal cavity (
Fig. 57
); intercoxal process of ventrite 1 broad, truncate anteriorly (
Figs. 5
,
9, 13
,
29
); ventrite 1 immediately behind the metacoxa is modified with a row of greatly enlarged deep pits (
e.g
.,
Figs. 5
,
9, 13
,
29
), and the aedeagus is strongly arched in lateral view (
e.g
.,
Figs. 11, 15
). The parameres are highly variable in dorsal view but are never of the truncate/flared
type
. Additionally, the genus can be separated from
Goajiria
because the male profemur is usually not armed; if so, the tooth is in the basal third and the male mesofemur is without a setose patch below in the basal half.
Redescription.
Length
4.8–10.6 mm
, width
1.5–5.3 mm
. Body (
Fig. 1
) black, except at least apical 3 antennomeres typically fuscous, sometimes entire antenna reddish black, palps reddish brown, sometimes tarsi reddish brown (teneral individuals may be reddish brown); typically matte, sometimes shiny, but never metallic; body variously rounded laterally either as a whole or prothorax and elytra separately; body convex; glabrous or with golden or light colored, erect setae.
Head (
Fig. 2
) small, somewhat trapezoidal, transverse, epistoma evenly convex or flattened, epistomal margin emarginate; variously punctate. Labrum visible dorsally; variously punctate; 2 tufts of golden setae on apical margin. Antenna (
Fig. 2
) 11-segmented, weakly clavate to clavate. Eyes small; divided by genal canthus; dorsal and ventral portions of eye roughly equal in size, variably shaped from perfectly rounded to ovate. Gula with transverse ridge at sides prolonged into erect, hornlike tubercles, especially enlarged in some species.
Pronotum (
Fig. 1
) usually widened posteriorly, sometimes widest at middle; apical margin usually evenly, broadly emarginate; sides variable; basal width greater than or equal to width across humeri; basal margin bisinuate; dorsal surface typically broadly, evenly convex; all margins narrowly beaded, except usually obsolete at middle of anterior margin; typically punctate, punctation of variable size and density; variously setose. Hypomeron smooth to rugulose, variously punctate. Prosternal process variable in shape and length, punctate.
Scutellum (
Fig. 4
) variable, triangular or rounded, wider than long. Elytra (
Fig. 2
) fused together; humeral angles narrowed; sometimes constricted in anterior 1/3 of elytra before humerus to less than basal width of pronotum; elytral striae 7 and 8 not both reaching base of elytra, anterior end of stria 8 curved laterad, ending at lateral stria, cut off from base of elytra by stria 7, which also curves laterad and ends either at humeral angle or at lateral stria; elytral striae variable from deeply impressed to effaced; typically strongly punctate; intervals usually convex.
Mesoventrite (
Fig. 2
) short, deeply impressed to receive prosternal process; variously punctate or rugulose or glabrous. Metathoracic wings extremely reduced or absent. Metaventrite (
Fig. 2
) short, usually equal to or shorter than mesocoxal cavity; typically with punctate on anterior border behind mesocoxae.
Leg (
Fig. 2
) surfaces variably setose and punctate; relatively short. Femora sometimes swollen, bulging. Male profemur not armed, except rarely with small spine basally, male mesofemur without setose patch below in basal 1/2. Protibia typically expanding gradually in distal 2/3; surface with variably stout spines. Male protarsus with tarsomeres 1–3 expanded, tarsomere 2 widest, typically 1.5–2.0X width of tarsomere 4, ventrally with golden, densely setose pads; female protarus not expanded. Mesotarsus in male sometimes with tarsomeres 1–3 expanded or weakly expanded, ventrally with densely setose pads; female mesotarsus not expanded. Metatarsus narrow, without setose pads.
Abdominal ventrites variably punctate; intercoxal process of ventrite 1 broad, truncate anteriorly; male ventrites 1–3 typically slightly concave medially; female ventrites 1–3 slightly convex or flattened medially; anterior border of ventrite 1 with row of distinct heavy pits at anterior edge bordering posterior margin of hind coxae, sometimes punctures extending onto intercoxal process (sometimes ventrites 2 and 3 with similar punctation). Aedeagus (
Figs. 3, 7
) with basal piece strongly arched in lateral view; parameres relatively stout, often curved and otherwise modified, never truncate/flared
type
; lateral margin of parameres straight or undulate; tips often upturned.
Larvae.
Some purported larvae have been described (
Marcuzzi and Cravera 1981
). However, we have not confirmed the association between the adult and larvae, and given the massive misidentifications discovered in Marcuzzi’ s work (
Ivie and Hart 2016
), none of these descriptions can be trusted to even belong to this genus.
Biology.
Diastolinus
are commonly collected under stones, driftwood, and other debris in relatively dry habitats. It appears that the most common habitats for
Diastolinus
species
are seasonally dry tropical woodlands. Specimens have been found mostly by unspecified general hand collecting, though some have been taken in pitfall traps, leaf litter samples, under fallen vegetation such as cacti, or in nests of the brown booby nests,
Sula leucogaster
(Boddaert)
. Collecting localities vary from low lying coastal thorn scrub, dunes and beaches at 0 m, and up to
2,100 m
above sea level in dry tropical forest.
Distribution.
Species of
Diastolinus
are known from the Greater Antilles (Hispaniola,
Puerto Rico
,
US Virgin Islands, British Virgin Islands
), and the Lesser Antilles (Sombrero to
Grenada
).
Recognition of Informal Species-Groups within
Diastolinus
The members of
Diastolinus
currently recognized are diverse in form and size, however, they can be separated into three informal speciesgroups that are useful in discussing specimens, although they probably do not all constitute monophyletic groups. The “clathratus” speciesgroup (
Table 1
) includes some of the oldest names originally associated with
Diastolinus
, including the
type
species of the genus. The “clathratus” species-group is distributed throughout
Puerto Rico
, the
Virgin Islands
, and the northern Lesser Antilles south to
Dominica
. The species in this group (
Figs. 1–29
) are oval, moderate to large in size (
6.9–10.6 mm
long), with the anterior third of the elytra not constricted, the base of the elytra equal to or subequal to the width of the base of the pronotum, and the male protibiae never armed.
The “sellio” species-group (
Table 2
) is distributed in southern Hispaniola,
Puerto Rico
, and the
Virgin Islands
. The members of this species-group (
Figs. 30–79
) are small to large (
6.1–10.6 mm
in length) and characterized by the constriction of the anterior third of the elytra, anterior of the point where stria 8 joins the lateral stria, to less than the basal width of the pronotum. The elytra may expand anterior of the constricted point to subequal the width of the posterior edge of the pronotum, or the posterior edge of pronotum may be wider than the base of the elytra. The femora are typically swollen and clavate, especially in the male fore legs. The male protibiae are often armed with a distinct, stout spine.
The “ctesicles” species-group (
Table 3
) is distributed in the Lesser Antilles from
Martinique
south to
Grenada
. They are small in size (
4.8– 6.5 mm
in length), elongate, with the pronotum widest before the mid-point, and the elytra slightly broader across the humeri than the base of the pronotum and entirely covered in large, evenly spaced punctures (
Figs. 80–97
).
KEY TO THE SPECIES OF
DIASTOLINUS
Note. Specimens should be cleaned prior to using the key (see Material and Methods).
1. Anterior 1/3 of elytra, anterior of the point where 8
th
stria joins lateral stria, constricted to less than basal width of pronotum (
Figs. 30
,
36
,
61
,
68
), elytra sometimes slightly expanded anteriorly from constricted point to subequal width of posterior edge of pronotum, or posterior edge of pronotum wider than base of elytra; femora typically swollen (
Fig. 61
), especially in male forelegs, somewhat less so in females. Hispaniola,
Puerto Rico
,
Virgin Islands
...... 2
1′. Anterior 1/3 of elytra not constricted, base of elytra equal in width to base of pronotum (
Fig. 1
); femora not swollen.
Puerto Rico
,
Virgin Islands
, Lesser Antilles .................. 10
2. Elytra not distinctly costate (
Fig. 56
); interstriae not convex; base of elytra, including humerus, much narrower than pronotum. Hispaniola..................................................3
2′. Elytra costate (
Fig. 2
), interstriae convex; base of elytra subequal to pronotal width or if narrower, elytra with deep punctures. Hispaniola,
Puerto Rico
,
Virgin Islands
....4
3. Upper surface dull with short yellowish pubescence (
Fig. 56
); elytra with strial punctation equal to interstrial punctation, punctation dense, small and shallow; male protibia armed with multiple short teeth, not a single distinct spine (
Fig. 57
).
Dominican Republic
(
Pedernales Province
) .................
D. gladiator
Table 1.
List of species included in the “clathratus” species-group. * indicates WIBF specimen to be deposited in NMNH.
|
Species name
|
Taxonomic status
|
Type repository
|
|
Diastolinus chalumeaui
Hart and Ivie
|
NEW SPECIES |
WIBF* |
|
Diastolinus clathratus
(Fabricius)
|
VALID SPECIES |
ZMUC |
|
Diastolinus clavatus
Mulsant and Rey
|
VALID SPECIES |
MNHN? |
|
Diastolinus hummelincki
Marcuzzi
|
JUNIOR SYNONYM |
HNHM |
|
Diastolinus mulsanti
Marcuzzi and D’ Aguilar
|
JUNIOR SYNONYM |
HNHM |
|
Diastolinus leewardensis
Hart and Ivie
|
NEW SPECIES |
WIBF* |
|
Diastolinus perforatus
(Schönherr)
|
VALID SPECIES |
NHRS |
|
Diastolinus shieli
Hart and Ivie
|
NEW SPECIES |
NMNH |
Table 2.
List of species included in the “sellio” species-group. * indicates WIBF specimen to be deposited in NMNH.
|
Species name
|
Taxonomic status
|
Type repository
|
|
Diastolinus azuaensis
Hart and Ivie
|
NEW SPECIES |
WIBF* |
|
Diastolinus coarctatus
(Mulsant and Rey)
|
VALID SPECIES |
MNHN? |
|
Diastolinus estebani
Garrido
|
JUNIOR SYNONYM |
MNHC |
|
Diastolinus desecheo
Hart and Ivie
|
NEW SPECIES |
OSUC |
|
Diastolinus doyeni
Hart and Ivie
|
NEW SPECIES |
AMNH |
|
Diastolinus espoloni
Garrido
|
VALID SPECIES |
HPPR |
|
Diastolinus gladiator
(Garrido)
|
VALID SPECIES |
MNHC |
|
Diastolinus tibidens
(Quensel)
|
VALID SPECIES |
NHRS |
|
Diastolinus vaderi
Hart and Ivie
|
NEW SPECIES |
FSCA |
|
Diastolinus victori
Garrido
|
NEW SPECIES |
MSNG |
3′. Upper surface shiny, glossy, without setae (
Fig. 68
); elytra with large, deep strial punctation, interstrial punctation minute and sparse; male protibia armed with a single distinct spine.
Haiti
.........................
D. vaderi
4. Upper surface covered in relatively long yellowish pubescence; elytral pubescence subequal to or longer than width of interstriae ......................................... 5
4′. Upper surface with few setae, if present, setae short and sparse; elytral pubescence, if present, less than 1/2 width of interstriae........................................... 7
5. Base of elytra subequal to width of pronotum (
Figs. 30
,
36
); scutellum short, mostly hidden and crescent-shaped if visible; body robust, very convex, greater than
8.5 mm
in length. Hispaniola ......................6
5′. Base of elytra, including humeri, much narrower than pronotum (
Fig. 63
); scutellum large, distinct, and triangular; body less robust, not as convex, less than
7.5 mm
in length.
Puerto Rico
,
Virgin Islands
............ .................................................
D. tibidens
6. Male protibia armed with a single distinct spine (
Fig. 33
); scutellum short, but visible and crescent-shaped (
Fig. 30
); pronotum (
Fig. 31
) with long, dense, yellow setae greater than or subequal in length to elytral setae; punctation on pronotal disk typically spaced greater than diameter of a puncture.
Dominican Republic
(
Azua Province
) ....... ..............................................
D. azuaensis
6′. Male protibia unarmed; scutellum very short, mostly hidden (
Fig. 36
); pronotum with setae shorter than elytral setae; punctation on pronotal disk typically spaced less than or equal to the diameter of a puncture (
Fig. 37
).
Dominican Republic
(
Pedernales Province
) ..........
D. coarctatus
7. Pronotum with subrugose, sometimes confluent punctures antero-laterally on disc (
Fig. 52
); male protibia armed with a single distinct spine (
Fig. 51
).
Dominican Republic
(
Pedernales Province
) .................
D. espoloni
7′. Pronotum with punctures normal, not subrugose, distinctly separate; male protibia unarmed.
Puerto Rico
and satellite islands .... 8
8. Abdominal ventrites nearly glabrous, with at most a few white or pale setae; gular horn short, length less than 1.5X basal width. Body less than
9 mm
in length (
Fig. 46, 48
).
Puerto Rico
......................................
D. doyeni
8′. Abdominal ventrites with some yellow setae; gular horn large and prominent, length nearly 2X basal width. Body greater than
9.3 mm
in length.......................................................... 9
9. Elytra with strial punctation relatively shallow (
Fig. 41
); bead on pronotal anterior margin complete (
Fig. 100
); body somewhat oblong; punctation on abdominal ventrites 2 and 3 shallow (
Fig. 43
); parameres not spade-shaped, gently tapering distally (
Figs. 44, 45
).
Puerto Rico
(Desecheo Island)............ ...............................................
D. desecheo
Table 3.
List of species included in the “ctesicles” species-group. * indicates WIBF specimen to be deposited in NMNH.
|
Species name
|
Taxonomic status
|
Type repository
|
|
Diastolinus hoppae
Hart and Ivie
|
NEW SPECIES |
WIBF* |
|
Diastolinus insularis
(Champion)
|
VALID SPECIES |
BMNH |
|
Diastolinus maritimus
(Champion)
|
VALID SPECIES |
BMNH |
9′. Elytra with strial punctation deeper (
Fig. 73
); bead on pronotal anterior margin obsolete medially (
Fig. 101
); body elongate; punctation on abdominal ventrites 2 and 3 larger and deeper (
Fig. 77
); parameres spadeshaped, abruptly tapering distally (
Figs. 78, 79
).
Puerto Rico
(main island and southern satellite islands)...........................
D. victori
10. Entire body surface, dorsal and ventral, entirely covered in large, evenly spaced punctures (
Figs. 80
,
86
,
92
); upper surface covered with yellow pubescence; body less than
7 mm
in length (typically
4.8–6.5 mm
). Southern Lesser Antilles (
Martinique
,
St. Lucia
,
St. Vincent
,
Grenada
) ............................. 11
10′. Dorsal surface of pronotum and ventral surface of body not entirely covered in large, evenly spaced punctures (
Figs. 24, 28
), punctation small, sparse or minute on ventrites especially, dorsal surface variable; upper surface with few setae; body greater than
6.9 mm
in length (typically greater than
7.8 mm
).
Puerto Rico
,
Virgin Islands
, northern Lesser Antilles south to
Dominica
......13
11. Strial punctation deeply impressed with punctures commonly interrupting and overflowing onto interstriae (
Figs. 86, 88
,
92, 94
).
St. Vincent
,
Grenadines
,
Grenada
..... 12
11′. Strial puncation shallower, punctures rarely interrupting and overflowing onto interstriae (
Figs. 80, 82
).
Martinique
,
St. Lucia
.......... ..................................................
D. hoppae
12. Elytra strongly costate, intervals narrow and somewhat shiny, punctation very heavily impressed (
Figs. 87, 88
); lateral margin of pronotum somewhat angular; parameres with nearly straight apical margin (
Fig. 90
).
St. Vincent
..................................
D. insularis
12′. Elytra weakly costate, intervals broad and opaque, punctation not as heavily impressed (
Figs. 93, 94
); lateral margin of pronotum evenly rounded; parameres rounded at apex, with apical margin weakly emarginate (
Fig. 96
).
Grenada
,
Grenadines
(Mustique) .............................................
D. maritimus
13. Pronotal disc covered with many short, erect, usually yellowish setae, at least 1–2X length of diameter of pronotal punctation (setae rarely worn off pronotal disc, but remain visible on the lateral edges of pronotum) (
Figs. 16, 20
).
Puerto Rico
, St. Croix, Saba,
St. Eustatius
,
St. Kitts
,
Nevis
,
Barbuda
,
Antigua
, Montserrat,
Redonda
................... 14
13′. Pronotal disc not apparently setose, laterally some short setae subequal to length of puncture diameter (
Figs. 8, 12
,
24
).
Puerto Rico
, Mona,
Virgin Islands
(except St. Croix), Sombrero,
Anguilla
Bank,
Guadeloupe
,
Dominica
.........................18
14. Elytra glossy, shiny; some strial punctures confluent; body shape oval (
Fig. 1
). St. Croix .............................
D. clathratus
14′. Elytra matte black, not shiny (
Figs. 16, 20
); strial punctures separate and distinct; body somewhat narrower and more parallelsided.
Puerto Rico
, Saba,
St. Eustatius
,
St. Kitts
,
Nevis
,
Barbuda
,
Antigua
, Montserrat,
Redonda
...................................................... 15
15. Lateral margins of pronotum evenly rounded (
Figs. 16, 20
), widest point appearing anterior of hind angles; typically 2 or fewer punctures evident on sutural stria just posterior to scutellum (specimens must be clean); gular horn small, less prominent, length less than 1.5X basal width. Saba,
St. Eustatius
,
St. Kitts
,
Nevis
,
Barbuda
,
Antigua
, Montserrat,
Redonda
...................16
15′. Lateral margins of pronotum widened posteriorly (
Figs. 42
,
75
), widest point apparently at hind angles; typically 3 or more punctures evident on sutural stria just posterior to scutellum (specimens must be clean); gular horn large and prominent, length nearly 2X basal width (
Fig. 76
).
Puerto Rico
(and satellite islands).................................. 17
16. Elytra with dense, long, typically yellowish setae; parameres tapering gradually distally (
Figs. 20–23
).
Redonda
.................
D. shieli
16′. Elytra with short, sparse, typically white or pale setae; parameres tapering at a sharper angle distally (
Figs. 16 –19
). Saba,
St. Eustatius
,
St. Kitts
,
Nevis
,
Barbuda
,
Antigua
, Montserrat ........
D. leewardensis
17. Elytra with strial punctation relatively shallow (
Fig. 41
); bead on pronotal anterior margin complete (
Fig. 100
); body somewhat oblong; punctation on abdominal ventrites 2 and 3 shallow (
Fig. 43
); parameres not spade-shaped, gently tapering distally (
Figs. 44, 45
).
Puerto Rico
(Desecheo Island).........................................
D. desecheo
17′. Elytra with strial punctation deeper (
Fig. 73
); bead on pronotal anterior margin obsolete medially (
Fig. 101
); body elongate; punctation on abdominal ventrites 2 and 3 larger and deeper (
Fig. 77
); parameres spadeshaped, suddenly tapering distally (
Figs. 78, 79
).
Puerto Rico
(main island and southern satellite islands) ..............................
D. victori
18. Legs robust, metatarsus expanded, tarsomere 1 less than 1.5X length of tarsomere 2 (
Fig. 27
); abdominal ventrites 2 and 3 often without row of distinct, heavy punctures at anterior edge of ventrite, instead with at most 1 or 2 shallow punctures near lateral edge of ventrite (
Fig. 28
). Sombrero,
Anguilla
Bank (
Anguilla
,
St. Barthélemy
,
St. Martin
)............. ...................................................
D. perforatus
18′. Legs gracile, metatarsus not expanded, tarsomere 1 more than 2X length of tarsomere 2; abdominal ventrites 2 and 3 with row of distinct, heavy punctures at anterior edge of ventrite (
Figs. 9, 13
).
Puerto Rico
, Mona,
Virgin Islands
(excluding St. Croix),
Guadeloupe
,
Dominica
...........................19
19. Abdominal ventrites with regularly spaced punctures (besides row of anterior punctures) and yellowish setae; parameres broadly rounded distally and with a weakly sinuate lateral margin (
Figs. 10, 11
).
Guadeloupe
,
Dominica
.................................
D. chalumeaui
19′. Abdominal ventrites with sparse, tiny punctures (besides row of anterior punctures) and very few white or pale setae; parameres tapering almost to a point distally and with straight lateral margin (
Figs. 14, 15
).
Puerto Rico
, Mona, northern
Virgin Islands
(excluding St. Croix)................................
D. clavatus
“Clathratus” Species-Group
Diagnosis.
This species-group can be distinguished by the combination of the oval body shape, moderate to large size (
6.9–10.6 mm
long), anterior 1/3 of the elytra not constricted, base of the elytra equal to or subequal to the width of the base of pronotum, and male protibiae never armed. The “clathratus” species-group is distributed throughout
Puerto Rico
, the
Virgin Islands
, and the Northern Lesser Antilles south to
Dominica
(
Fig. 102
).
Figs. 1–7.
Diastolinus clathratus
.
1)
Dorsal habitus;
2)
Holotype, lateral view;
3)
Aedeagus, dorsal view;
4)
Humeral angle, dorsal view;
5)
Abdominal ventrites;
6)
Holotype
label;
7)
Aedeagus, lateral view.
Figs. 8–15.
Diastolinus chalumeaui
, holotype:
8)
Dorsal habitus;
9)
Abdominal ventrites;
10
) Aedeagus, dorsal view;
11)
Aedeagus, lateral view.
Diastolinus clavatus
:
12)
Dorsal habitus;
13)
Abdominal ventrites;
14)
Aedeagus, dorsal view;
15
) Aedeagus, lateral view.
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.
Figs. 24–29.
Diastolinus perforatus
.
24)
Dorsal habitus;
25)
Head;
26)
Aedeagus, dorsal view;
27)
Lateral habitus;
28)
Abdominal ventrites;
29)
Aedeagus, lateral view. Figs. 24–26 and 28–29 of Anguilla specimen, Fig. 27 of St. Barthélemy specimen.
Figs. 30–35.
Diastolinus azuaensis
, holotype.
30)
Dorsal habitus;
31)
Pronotum;
32)
Aedeagus, dorsal view;
33)
Fore leg;
34)
Abdominal ventrites;
35)
Aedeagus, lateral view.
Figs. 36–40.
Diastolinus coarctatus
.
36)
Dorsal habitus;
37)
Pronotum;
38)
Abdominal ventrites;
39)
Aedeagus, dorsal view;
40)
Aedeagus, lateral view.
Figs. 41–45.
Diastolinus desecheo
, paratype.
41)
Dorsal habitus;
42)
Pronotum;
43)
Abdominal ventrites;
44)
Aedeagus, dorsal view;
45)
Aedeagus, lateral view.
Figs. 46–50.
Diastolinus doyeni
, holotype.
46)
Dorsal habitus;
47)
Pronotum;
48)
Abdominal ventrites;
49)
Aedeagus, dorsal view;
50)
Aedeagus, lateral view.
Figs. 51–55.
Diastolinus espoloni
.
51)
Dorsal habitus;
52)
Pronotum;
53)
Abdominal ventrites;
54)
Aedeagus, dorsal view;
55)
Aedeagus, lateral view.
Figs. 56–60.
Diastolinus gladiator
.
56)
Dorsal habitus;
57)
Ventrolateral habitus;
58)
Abdominal ventrites;
59)
Aedeagus, dorsal view;
60)
Aedeagus, lateral view.
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.
Figs. 68–72.
Diastolinus vaderi
.
68)
Paratype, dorsal habitus; Holotype:
69)
Pronotum;
70)
Abdominal ventrites;
71)
Aedeagus, dorsal view;
72)
Aedeagus, lateral view.
Figs. 73–79.
Diastolinus victori
.
73)
Paratype, dorsal habitus;
74)
Paratype, labels;
75)
Pronotum;
76)
Gular horn;
77)
Abdominal ventrites;
78)
Aedeagus, dorsal view;
79)
Aedeagus, lateral view.
Figs. 80–85.
Diastolinus hoppae
, paratype.
80)
Dorsal habitus;
81)
Head and thorax, ventral view;
82)
Humeral angle, lateral view;
83)
Abdominal ventrites;
84)
Aedeagus, dorsal view;
85)
Aedeagus, lateral view.
Figs. 86–91.
Diastolinus insularis
, lectotype.
86)
Dorsal habitus;
87)
Pronotum;
88)
Lateral habitus;
89)
Abdominal ventrites;
90)
Aedeagus, dorsal view;
91)
Aedeagus, lateral view.
Figs. 92–97.
Diastolinus maritimus
. Lectotype:
92)
Dorsal habitus;
93)
Pronotum. Paralectotype:
94)
Lateral habitus;
95)
Abdominal ventrites;
96)
Aedeagus, dorsal view;
97)
Aedeagus, lateral view.
Figs. 98–101.
Diastolinus
species.
98)
D. desecheo
, pronotal bead;
D. clavatus
:
99)
Pronotal bead;
100)
Aedeagus - a) Ventral view, b) Lateral view;
101)
Ovipositor - a) Dorsal view, b) Ventral view.
Fig. 102.
Map of the distributions of
Diastolinus
species-groups on Hispaniola, Puerto Rico, the Virgin Islands, and the Lesser Antilles.
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.
Fig. 105.
Map of the distributions of the “clathratus” species-group of
Diastolinus
species
on Puerto Rico and the Virgin Islands. Symbols represent island distributions, not all collection events.
Fig. 103.
Map of the distributions of
Diastolinus
species
on Hispaniola.
DISCUSSION
Of the initial 13 historic
Diastolinus
species
recognized at the beginning of this study, ten were found to be valid. An additional eight previously undescribed species were identified, for a current total of 18. Of these eight unnamed species, three had an existing nomenclatural history under misidentifications, some going back as far as 1859. Hundreds of misidentified island records were discovered and corrected, changing a picture of widespread, dispersalist taxa making more-orless random multispecies assemblages across the eastern Caribbean into a far more informative pattern of three groups of species, ordered in adjacent regions, with most species clearly limited to banks exposed during the Pleistocene.
The “sellio” species-group (
Fig. 102
) is limited to the southern portion of Hispaniola (
Fig. 103
), the islands of the Puerto Rican Bank, and tiny Desecheo in the Mona Passage between the two (
Fig. 104
). It is unique in having multiple sympatric species on both Hispaniola and
Puerto Rico
. The “clathratus” species-group is centrally located within the range of the genus (
Fig. 102
), occupying most islands in the northeastern Caribbean arc from Mona to
Dominica
(
Figs. 105
,
106
). The “ctesicles” species-group, with its unique morphology, is limited to the Windward Islands (
Figs. 102
,
106
). More exploration of
Martinique
and
the Grenadines
may add to the range and diversity of this group. Both the “clathratus” and “ctesicles” species- groups have proven to have strictly allopatric species, with no geographic overlap at all, in stark contrast to the picture painted by the pre-revision literature.
Fig. 106.
Map of the distributions of
Diastolinus
species
in the Lesser Antilles.
The origin and biogeography of the early diversification of the genus will require a phylogenetic analysis to discuss in an appropriate manner, including a test of the monophyly of both the genus and species-groups. The absence of the “sellio” species-group, and
Diastolinus
in general, from the northern and central paleoislands of Hispaniola is interesting. The limitation, with one small deviation in
D. azuaensis
, of
Diastolinus
species
to south of the Cul-de-Sac/Enriquillo Depression, roughly corresponding to the southern paleoisland, deserves more indepth investigation. Clearly, there is no lack of suitable habitat to the north, nor has there been a lack of collecting effort, as material of the ecologically similar
Xerolinus
is abundant (
Ivie and Hart 2016
). Emergent parts of northern/central Hispaniola and the Puerto Rican Bank have been available for habitation since at least the Eocene (Iturralde and MacPhee 1999; McPhee
et al
. 2003), but not until the Miocene was the southern paleoisland of Hispaniola emergent (
loc. cit
.).
The northern/central paleoisland did not connect to the southern until the Miocene, after
Puerto Rico
and central Hispaniola were separated by the origin of the Mona Passage in the Oligocene (McPhee
et al
. 2003). It is tempting to suggest that the ancestor of the “sellio” species-group originated on the Puerto Rican Bank after the Hispaniola/
Puerto Rico
separation (Oligocene), and a propagule,ight have reached the southern paleoisland of Hispaniola before the north/south paleoislands fused (Miocene).
The “clathratus” species-group, with its generalized morphology, may represent the ancestral form, and its central location could indicate the area of origin was the Puerto Rican Bank. Again, its absence from Hispaniola indicates an origin after the formation of the
Mona
Passage in the Oligocene. If it is truly the ancestral group of the other species-groups, and if those other groups are monophyletic, then the origin of
Diastolinus
would be no older than the Oligocene.
“Clathratus” Species-Group
What can be discussed more appropriately is the correspondence of modern distributions of species to Pleistocene banks. In almost every case, species are limited to groups of islands that were connected by land or close-adjacent during the eustastic minima of the late Pleistocene.
Diastolinus clavatus
, for instance, occurs over a large area from
Puerto Rico
throughout the northern
Virgin Islands
to
Anegada
, an area that was the island of Greater
Puerto Rico
18,000 ybp. Its allopatric sister-species and fellow
Virgin Islands
species,
D. clathratus
, is limited to the St. Croix Bank, which was its own island to the south of Greater
Puerto Rico
.
Diastolinus tibidens
and
D. victori
also cleave closely to Greater
Puerto Rico
, the former ranging from
Puerto Rico
to
Virgin Gorda
, and the later sharing
Puerto Rico
and several of the cays to the south. Outliers of
D. tibidens
on Mona and St. Croix may be the result of human introductions. The extensive trade in agricultural products between St. Croix and St. Thomas during the
Danish West Indies
period would provide the means for the St. Croix introduction.
D. chalumeaui
Hart and Ivie
,
new species
........... ......................................... Guadeloupe,
Dominica
D. clathratus
(
Fabricius, 1792
)
........................... ....................................St. Croix, Buck Is. (STT)
D. clavatus
Mulsant and Rey, 1859
...................... Mona, Monito,
Puerto Rico
,
Vieques
, St. Thomas, Saba Is. (STT), Buck Is. (STT), Great St. James, Little St. James, Thatch Cay (STT), St.John, Frenchman Cay (TOR),
Tortola
, Great
Tobago
(Jost van Dyke), Guana TOR), Marina Cay (TOR), Great Camanoe (TOR), Beef Is. (TOR), Peter Is. (TOR), Dead Chest (TOR), Ginger Is. (VG), George Dog (VG), Prickly Pear Is. (VG),
Virgin Gorda
,
Anegada
.
D. hummelincki
Marcuzzi, 1962
,
new synonymy
D. mulsanti
Marcuzzi and D’ Aguilar, 1971
,
new synonymy
D. leewardensis
Hart and
Ivie, 2016
,
new species
.... ......
Antigua
,
Barbuda
, Saba,
St. Eustatius
,
St. Kitts
,
Nevis
,
Montserrat
.
D. perforatus
(
Schönherr, 1806
)
........................... ......... Sombrero (ANG),
Anguilla
, Prickly Pear Cay (ANG),
St. Martin
, Tintamarre (STM),
Other examples of this
type
of distribution are
D. perforatus
on the
Anguilla
Bank;
D. leewardensis
on the Statia Shelf, adjacent Barbuda-Antigua Shelf, plus nearby
Saba
and
Montserrat
;
D. chalumeui
on the three Banks in
Guadeloupe
(
Guadeloupe
Bank, Les Saintes Bank and Marie-Galante Bank) and nearby
Dominica
;
D. hoppae
on the island pair of
St. Lucia
and
Martinique
; as well as
D. maritimus
on the
Grenadine
Bank. The outlier of
D. perforatus
on Sombrero is explained by the movement of sand from
Anguilla
to Sombrero during the building of the lighthouse. The species was limited to the remains of the sand pile near the loading area when Sombrero was surveyed in 1999 (MAI and J. Runyon, personal observation). The sharing of species between
Guadeloupe
and
Dominica
, and
Martinique
and
St. Lucia
islands not known to be linked during the Pleistocene, are mirrored in other groups, such as the scarab genus
Dynastes
Kirby, 1825
and the weevil genus
Cholus
Germar, 1824
. Single island endemics on Redonda (
D. shieli
) and
St. Vincent
(
D. insularis
) are on islands that remained separate from all others during the Pleistocene. These patterns offer an excellent place to study divergence times, both between species and on islands within the various banks.
CHECKLIST OF THE SPECIES OF
DIASTOLINUS
MULSANT AND
REY
The species of
Diastolinus
are alphabetically ordered within species-group.
Island
names follow
Ivie and Hart (2016)
.
St. Barthélemy
, Île de la Fourche
D. shieli
Hart and
Ivie, 2016
,
new species
........... ............................................................Redonda