Decorosa neiba, Opitz, 2008

Opitz, Weston, 2008, Classification, Natural History, and Evolution of Epiphloeinae (Coleoptera: Cleridae). Part V. Decorosa Opitz, a New Genus of Checkered Beetles from Hispaniola with Description of Its Four New Species, American Museum Novitates 3628 (1), pp. 1-20 : 11-17

Decorosa neiba , new species

Figures 40, 41, 43 , 46.

HOLOTYPE: Female. DOMINICAN RE- PUBLIC: Elias Pina. Cierra de Neiba , 9.1 km WSW Hondo Valle, 18-41-38N, 71- 46-56W, 1856 m, 25 June 2003, J. Rawlins, C. Young, R. Davidson, C. Nunez, P. Acevedo,

M. de la Cruz, wet montane forest with pine, malaise trap, Carnegie Museum Specimen Number CMNH-356.509 ( CMNH). (Specimen minuten pin mounted on neoprene block; gender label and metathoracic wing mounted on support card; locality label; holotype label) .

PARATYPES: One specimen: Dominican Republic: San Juan: Sierra de Neiba, 9.4 km SSW El Cercado, 18 ° 39 9 N 71 ° 32 9 W, 22-VI- 2003, 1974 m, mature pine forest, Malaise trap, R. Davidson, C. Nuñez, C. Young, J. Rawlins, P. Acevedo, M. de la Cruz ( WOPC, 1) .

DIAGNOSIS: From superficially similar specimens of D. aladecoris , D. neiba specimens may be distinguished by the shape of the pronotum. Specimens of A. neiba have a proportionally wider pronotal posterior margin (compare figs. 42, 43). From other congeners these beetles are distinguished by the bicolorous coloration of the pronotum; the disc is dark brown and the anterior margin is reddish brown.

DESCRIPTION: Size: Length 4.0– 4.2 mm; width 1.6–1.8 mm. Integumental Color: Cranium and pronotum bicolorous, cranial disk dark brown, periphery reddish brown, pronotal disc dark brown, anterior margin reddish brown; antennae unicolorous, mostly yellow, some funicular articles infuscated; elytra as in figure 41; legs mostly yellow, femora and tibiae infuscated; venter dark brown. Vestiture: Cranium and pronotum densely vested with pale decumbent setae. Head: Vertex much wider than width of eye (13:25); ratio of head width to pronotal width 1.06 (57:54); antennal form similar to antenna depicted in figure 4. Thorax: Pronotum only slightly longer than broad (53:52); pronotal lateral tubercle obtuse; anterior margin slightly wider than posterior margin (48:47); apical region of protibial anterior margin with three spines; seventh row of elytral punctations begins slightly anterior to elytral middle. Abdomen: Aedeagus as in figure 40.

VARIATION: The available specimens are quite homogeneous.

NATURAL HISTORY: The two available specimens were collected in a Malaise trap in mountain forest laden with pine, at 1857 and 1974 m.

DISTRIBUTION (fig. 46): Known only from the highlands of Sierra de Neiba, in the San Juan Province of the Dominican Republic.

ETYMOLOGY: The trivial name, neiba , constitutes a noun in apposition and refers to the type locality.

REVIEW OF GREATER ANTILLEAN AND HISPANIOLOAN PALEOGEOGRAPHY

The literature is rich in facts, ideas, and syntheses about Caribbean biogeography/ geology ( Schwartz, 1980; Rosen, 1985; Liebherr, 1988; Mann et al., 1991; Donovan and Jackson, 1994; Woods and Sergile, 2001, and references therein) and more specifically about insect Hispaniolan zoogeography such as Woodruff and Sanderson (2004: 26). These stimulating contributions inspire attempts to make biographical sense of one’s taxonomic findings. My intent for this review of Antillean paleohistory is to provide a baseline of thoughts, along with additional comments related to insect findings, and summary for this and future analyses of Caribbean Cleridae taxa.

There is strong evidence from geology ( Khudoley and Meyerhoff, 1971: 129; van Fossen and Channell, 1988: 610; Perfit and Williams, 1989: 67; Heubeck et.al., 1991: 29; Draper et al.,1994: 143) and biology ( Williams, 1961: 2; Schwartz, 1980: 87, 1989: 489; Rosen, 1985: 652; Liebherr, 1988: 143; Woodruff and Sanderson, 2004: 27) to support the hypothesis that Hispaniola was once comprised of two islands, and that the northern part originated from an early Cretaceous-Eocene assemblage of insular rock whereas the southern portion originated from oceanic plateau rock, essentially the uplifted edge of Caribbean sea crust (Draper et al., 1994: 129). The two-island hypothesis and the prehistoric movement of the two landmasses that constitute Hispaniola have been incorporated into a paleogeographic model of West Indies mobility ( Pindell and Dewey, 1982: 202; Sykes et al., 1982: 10,669; Wage and Burke, 1983: 633; Rosen, 1985: 652; Perfit and Williams, 1989: 67; Pindell and Barrett, 1990: 405).

To explain biologic relationships between the northern and southern elements of Hispaniola, and those between Hispaniola and any other West Indies landmass, we must explore what is known about the geology and the paleotectonic and neotectonic events that eventually led to the island’s amalgamation. Moreover, the relative geologic ages of the two prehistoric landmasses is relevant to any discussion of their biogeography.

Donnelly (1988: 26) places the initial emergence of Greater Antillean terrain during the upper lower Cretaceous, about 105 Ma with Hispaniolan and Jamaican rocks included in the mix. Khudoley and Meyerhoff (1971: 152) suggest that ‘‘Most of the Greater Antilles were uplifted in the Miocene and later times.’’ Early Cretaceous rock elements in northern Hispaniola and late Cretaceous rock elements for the southwestern part of the island were reported by Draper et al. (1994: 129). This suggests that at least some portions of the crustal component of the Hispaniolan northern island may be more ancient than its southern counterpart. Rocks of the late upper Cretaceous (Maastrichtian stage, about 70 Ma) have been reported as a component of the southwestern Sierra de Bahoruco (Draper et al., 1994: 139). Of considerable relevance to the question of age of the southern portion of Hispaniola is the gymnosperm and angiosperm fossil discovery by Woodruff (1986: 32; also see Woodruff and Fritsch, 1989: 216) from the Larimer deposits of the Sierra de Baoruco considered Cretaceous by De Leon (1989: 85).

It has been hypothesized that Hispaniola’s southern terrain was in proximity with the Yucatán peninsula ( Rosen, 1985: 644) during early Eocene to late Paleocene (from 50– 65 Ma) and that crustal movements, involving fault generated tectonics, between the Caribbean and North American plates carried southern Hispaniola to its eventual welding with the northern Hispaniolan component; an amalgamation purported to have occurred during early Miocene (about 20 Ma) ( Heubeck et al., 1991: 29). Depending on one’s starting point, this means that the two islands have been separated from 35 to 85 million years of Caribbean evolution. And, while both islands experienced tumultuous geologic changes ( Donnelly, 1988: 27), likely environmental stresses from a bolide impact ( Hedges, 2001: 19; Opitz, 2005: 108), and presumably vicissitudinous climates ( Clench, 1963: 257), which must have had significant impacts on speciation and extinctions ( Curtis et al., 2001: 50; Morgan, 2001: 398), the aforementioned time span represents a wide window of opportunity for independent biologic evolution.

Moreover, during their eastward tectonic journey, the terrestrial components of Hispaniola would have experienced the kind of fault-based shifting and rotation that would have placed them in close geographic relationships with other Greater Antillean terrain. Draper and Barros (1988: 60, 1994: 82) suggest late Eocene geologic ties between Cuba and Hispaniola and based on Lygaeidae findings Baranowski and Slater (1998: 75) suggests vicariance between Cuba and Hispaniola, and possibly Puerto Rico. In a treatise of plant phylogeny involving trees and shrubs of Lyonia (Ericaceae) , Judd (2001: 72) discusses geologic relationships between western Cuba and southwestern Hispaniola and biotic relationships among Puerto Rico, north-central Hispaniola, and eastern Cuba.

If the welding of northern and southern Hispaniola occurred some 20 Ma ( Heubeck et al., 1991: 29) and speciation events requires about 3 million years, as suggested by Whitehead (1972: 308) in his work with ground beetles, then biologists interested in Hispaniolan beetle evolution have some measure for the temporal character of lower taxa divergence. This would be particularly useful for temporal analyses involving sister-group relationships between northern and southern Hispaniola and vicariant relationships among taxa from Hispaniolan and those of other Greater Antillean terrain.

DECOROSA EVOLUTIONARY CONSIDERATIONS

Two phylogenetic trees (figs. 44 and 45) were produced for Decorosa , one (fig. 44) prepared ‘‘by hand’’ and the other (fig. 45) computer generated. The computer analysis generated one parsimonious tree of 29 steps, CI of 100, and an RI of 100. Both phylogenies produced identical pairs of Decorosa sister species.

Paucity of Decorosa specimens and few distributional records usually preclude comprehensive discussion about phylogeny and zoogeography. But even a few tentative comments might be beneficial for future endeavors about the subject. Hispaniola has benefited from a flurry of entomological activities in recent years ( Schwartz, 1989: 489; Woodruff and Sanderson, 2004: 1; and various communications with insect collectors) and there has evolved a greater awareness of insect diversity in the Caribbean ( Liebherr, 1988). Some of these activities include greater insect collecting efforts, which have resulted in greater availability of Cleridae specimens.

The four Decorosa species are known only from the northern highlands of Hispaniola (fig. 45) with D. limatula , the sister species of the more northern D. iviei found in highlands east of Sierra de Neiba slightly north of the Enriquillo basin. Decorosa aladecoris and D. neiba , the more primitive members of the genus, are undoubtedly sympatric with the most derived D. iviei , which at the very least suggests some dispersal element in the early history of the genus.

As D. limatula is known from environs slightly north of the Enriquillo basin, one might presume a vicariant relationship between D. limatula with the more northern sister species D. iviei , as is the case between D. aladecoris and D. neiba . Discovery of limatula specimens from south of the Enriquillo basin would certainly support that possibility, and corroborate the likely north-south vicariance findings of Mertens (1939: 12), Williams (1961: 2), Schwartz (1980: 90), Judd (2001: 69), and Woodruff and Sanderson (2004: 26). As the most primitive members of the genus were collected from the northern portion of Hispaniola, I suspect that the northern component of the two paleoislands served as the ancestral terrain of the genus in which ancestral Decorosa stock B diverged to produce the aladecoris - neiba lineage and the more derived limatula - iviei lineage (fig. 44). More widespread northern collections of additional D. aladecoris and neiba specimens or absence of such material from the southern island would support the hypothesis and more credibly root the initial geographic divergence of the genus. Sister-group relationships of insect taxa between these two formerly insular highlands have been confirmed in Scarabaeidae ( Woodruff and Sanderson, 2004: 26) and in butterflies ( Schwartz, 1989: 489; Sourakov, 2000: 79).

The putative absence of Decorosa from western and southwestern Hispaniola could be a consequence of collecting bias or simply that captured specimens are unknown to me. I, like many other biologists, fear that extensive deforestation has eliminated a substantial Hispaniolan insect fauna, especially from western portions of the island ( Sergile and Woods, 2001: 547).

The divergence of ancestral Decorosa yield- ed the aladecoris line, which retained several primitive characteristics including normal eye size and nonnodal elytral punctations while acquiring an apotypic convex pronotum and loss of the pronotal anterior transverse depression. The sister taxon of this lineage, ancestor C, would have evolved a more flattened pronotum, the eyes became significantly reduced, and the elytral punctations acquired a binodal characteristic. This ancestor eventually yielded D. limatula and D. iviei each characterized as indicated in fig. 44. It remains to be seen whether D. limatula dispersed to southern portions of prehistoric Hispaniola from northern ancestral grounds, or whether the north-south distribution record of the limatula-iviei lineage expresses some manner of disjunction between the paleoislands of Hispaniola.

Figures

Figs. 39–43. Anatomical organs and habitus. 39. Decorosa aladecoris Opitz elytra, ventral view. 40–41. D. neiba Opitz (40, aedeagus; 41, habitus). 42. D. aladecoris, pronotum. 43. D. neiba, pronotum.

Fig. 46. Geographic distribution of Decorosa Opitz species.