Scelianoma compacta Franz & Zhang [FZ2017]

Franz, Nico & Zhang, Guanyang, 2017, Three new species of entimine weevils in Early Miocene amber from the Dominican Republic (Coleoptera: Curculionidae), Biodiversity Data Journal 5, pp. 10469-10469 : 10469

Scelianoma compacta Franz & Zhang [FZ2017] sp. n.

Materials

Type status: Holotype. Occurrence: catalogNumber: ARTSYS0000269 ; recordNumber: DR-888; recordedBy: Unknown; individualCount: 1; sex: Male; lifeStage: Adult; preparations: Amber inclusion; disposition: SEMC, on loan; otherCatalogNumbers: SEMC339; occurrenceID: 44a28738-bbf7-441d-8343-9adf009eb5b0; Taxon: scientificName: Scelianomacompacta; nameAccordingTo: Franz & Zhang 2017; namePublishedIn: Franz, N.M. & G. Zhang. 2017. Three new species of entimine weevils in Early Miocene amber from the Dominican Republic (Coleoptera: Curculionidae). Biodiversity Data Journal.; kingdom: Animalia; phylum: Arthropoda; class: Insecta; order: Coleoptera; family: Curculionidae; scientificNameAuthorship: Franz & Zhang, 2017; Location: country: Dominican Republic; stateProvince: La Vega; locality: Unknown mine ; decimalLatitude: 19; decimalLongitude: -70.666667; geodeticDatum: WGS84; georeferencedBy: N.M. Franz; georeferenceSources: Google Earth; georeferenceVerificationStatus: Verfied by Curator; Identification: identifiedBy: N.M. Franz & G. Zhang; dateIdentified: 01/15/2017; identificationReferences: Franz, N.M. & G. Zhang. 2017. Three new species of entimine weevils in Early Miocene amber from the Dominican Republic (Coleoptera: Curculionidae). Biodiversity Data Journal.; Event: verbatimEventDate: Early Miocene, Burdigalian; habitat: Amber inclusion, Early Miocene (Burdigalian); Record Level: modified: 24/01/2017 18:31; rights: http://creativecommons.org/publicdomain/zero/1.0/; rightsHolder: University of Kansas; bibliographicCitation: Franz, N.M. & G. Zhang. 2017. Three new species of entimine weevils in Early Miocene amber from the Dominican Republic (Coleoptera: Curculionidae). Biodiversity Data Journal.; institutionID: KU SEMC; collectionID: 0acac5fe-f0ec-4d9f-82f8-0dbb74888de2; institutionCode: SCAN; collectionCode: ARTSYS; ownerInstitutionCode: KU SEMC; basisOfRecord: FossilSpecimen; source: http://symbiota4.acis.ufl.edu/scan/portal/collections/individual/index.php?occid=25836759

Description

Male - habitus (Fig. 1). Length 9.0 mm, width 3.2 mm; shape in dorsal view elongate, length/width ratio = 2.8, widest near anterior 1/6 of elytra; shape in lateral view slightly compressed. Integument uniformly dark (black); surface sculpture of pronotum and elytra homogeneously foveate to lacunose, with deep, densely and regularly arranged, subcircular impressions, otherwise rugulose; integument covered with setae and scales, each most apparent on rostrum and legs; setae regularly arranged, dark brown, short and recurvate; scales circular and apparently densely arrangement and light to dark brown, though not well preserved in the type specimen.

Mouthparts. Mandibles equilateral, with 5-8 fine setae; mandibular scar positioned apicolaterally, projected. Maxillae with maxillary palps apparently 3-segmented (2 projecting palpomeres visible). Labium with prementum cordate, slightly wider than long; labial palps apparently 3-segmented.

Rostrum. Length 1.85 mm, rostral/pronotal length ratio 0.6, rostral length/width ratio 2.0 (though rostrum laterally compressed due to fossilization). Rostrum in dorsal view rectangular, anteriorly widened, anterodorsal margin weakly emarginate; epistoma with nasal plate (see Vaurie 1963) slightly angled in relation to posterior rostrum region, depressed, V-shaped; dorsal surface with a deep, median sulcus. Rostrum in lateral view anteriorly slightly expanded, occipital sutures extending to subapex and visible; scrobe lateral, nearly extending along entire rostrum though terminating anteriad of eye; antennal insertion near anterior 1/3. Antennae 11-segmented; scape extending to posterior margin of eye, and passing over eye (in idealized position); funicle 7-segmented, funicular antennomeres elongate, clavate; club 3-segmented, small, similar in length to funicular antennomeres V-VII.

Head. Eyes small, globular (strongly roundly protruded), laterally positioned, separated by distance shorter than anterior-to-posterior length of each eye; outline in lateral profile elliptical (horizontally more extended), anterior and posterior margins more strongly rounded, and with an anteocular invagination (see Franz 2012) extending from anteroventral to dorsoventral edge of eye. Head not constricted posteriad of eyes.

Thorax. Pronotum in dorsal view elongate-tubular, length/width ratio 1.5, pronotal/elytral length ratio 0.43; widest near mid point; surface foveate to lacunose (including lateral regions), lacunae somewhat variable in size and arranged in an off-set, honeycomb-like pattern; median sulcus absent. Pronotum in lateral view tubular, slightly arcuate; anterolateral margins straight (without postocular lobe), postocular vibrissae absent. Scutellum exposed by elytra, small, subcircular. Epipleura challenging to observe (distorted, obscured), though apparently similar to those of Scelianoma elydimorpha sec. Franz and Girón (2009). Prothoracic ventrite with anterior transverse sulcus; procoxal cavities positioned near mid point, contiguous. Mesothoracic ventrite with plumose-scopiform scales; mesocoxal cavities narrowly separated. Metathoracic ventrite challenging to observe; metacoxal cavities widely separated. Metendosternite not observed.

Legs. Prothoracic and metathoracic legs each longer than mesothoracic legs, generally similar to those of males of Scelianoma elydimorpha sec. Franz and Girón (2009). Profemoral/pronotal length ratio 0.8; profemur ventrally inermous. Protibial/profemoral length ratio 1.1; protibia slightly arcuate, apically exanded; anteromesal margin with 5-8 roundly triangular teeth, size increasing apically, each tooth distally with 1 brownish, spiniform seta; protibial apex with anterior margin truncate, setal comb absent, promucro similar in length to protarsal claw; protarsus with tarsomere I longer than II; II and III similar in length and jointly as long as V; protarsal claws paired, separate, simple. Mesotibiae and metatibiae nearly straight, apically obliquely truncate; metatibial apex with a narrow (linear) outer bevel ("corbel enclosed"; see Thompson 1992).

Elytra (Fig. 1). Length/width ratio 2.2; widest near anterior 1.4; anterior margins jointly minimally wider than posterior margin of pronotum, nearly straight; humeri absent; lateral margins slightly angulate: diverging along anterior 1/6, subrectate and slightly converging along posterior 1/6; posterior margins narrowly rounded. Elytra in lateral view with dorsal outline subplane along anterior 5/6, posterior 1/6 with distinctly angled, straight declivity, mesal elytral margin projected along angulation. Elytra with striae I-IX complete, stria X incomplete (challenging to observe); striae wider than intervals; punctures large, deep, foveate to lacunose, subcircular to elliptical, and arranged from stria to stria in an off-set, honeycomb-like pattern; intervals slightly elevanted and rounded.

Wings. Absent.

Abdomen. Venter with only abdominal ventrites VI and VII visible (and displaced by process of fossilization), each similar in length, and VII with posterior margin widely rounded. Pygidium entirely covered by elytra.

Terminalia. Terminalia not unambiguously observed; however, located just to the left side of the amber-included specimen are several displaced, distorted chitinous structures that apparently include the male spiculum gastrale and median lobe in more or less parallel orientation to the remainder of the specimen. Accordingly (with aforementioned caveats), the presumed spiculum gastrale is similar to that of Scelianoma elydimorpha sec. Franz and Girón (2009), and slightly shorter than the median lobe which narrowly linear in dorsal view and narrow and straight in lateral view, though more arcuate (inflected) along posterior 2/5, with dorso- and ventrolateral margins posteriorly continuously converging, and terminating in a narrowly rounded apex.

Female. Unknown.

Diagnosis

Generic placement. Scelianoma compacta [FZ2017] shares with Scelianoma elydimorpha Franz and Girón sec. Franz and Girón (2009) numerous phylogenetically informative traits inferred in Franz (2012) that substantiate this generic placement (see also Franz and Girón 2009 and Tables 1, 2, 3, 4, 5, 6). They include: character 18(1): rostrum with one dorsal, median sulcus; character 23(0): scrobe (of antenna) passing over eye in lateral profile; 26(1) rostrum (ventral side) with occipital sutures anteriorly extending to subapex of rostrum, anteriorly ascending and visible in lateral profile; 34(1): head with an anteocular invagination, extending from anteroventral to anterodorsal edge of eye; 35(1): head with eyes in dorsal profile entirely positioned on lateral surface of head; 58(2): metatibial apex with an outer bevel ("corbel enclosed"; see Thompson 1992); 62(1): elytra with humeri absent; 66(1): elytra with declivity in lateral profile strongly angulate ( Franz and Girón 2009); and 83(1): wings not developed (absent). This combination of character states is shared only between Scelianoma compacta [FZ2017] and Scelianoma elydimorpha sec. Franz and Girón (2009), rendering them monophyletic and thus congeneric in our expanded analysis.

Close extant relatives of Scelianoma Franz and Girón [FZ2017] include members of Artipus Sahlberg sec. O'Brien and Wibmer (1982) that frequently display a wider shape, a wider and dorsally more narrowly (and non-continuously) sulcate rostrum (character 40[1] of Franz 2012), with the scrobe and hence the antennal scape passing ventrad of the eye in lateral profile (and idealized position), and characteristically irregular (punctate to linear) dorsal pronotal foveae (character 43[1] of Franz 2012). We note, however, that Artipus sec. O'Brien and Wibmer (1982) is likely not a monophyletic, comprehensively sampled entity, and indeed a revision of this entity is underway (N.M. Franz, in preparation). The revision is unlikely to alter present inferences regarding the identity of Scelianoma [FZ2017].

Scelianoma [FZ2017] is also distinct from other extant Caribbean groups such as Apotomoderes Dejean sec. Franz (2010b) and Melathra Franz sec. Franz (2011) which have a head with a conspicuous postocular constriction (character 32[1]), a profemoral tooth (character 52[1]), and a less abruptly angulate elytral declivity (character 66[0]); all in accordance with Franz 2012).

Franz and Girón (2009) preferred a placement of Scelianoma sec. Franz and Girón (2009) in the tribe Eustylini Larcordaire 1863 [non-focal], but this was not supported in Franz (2012). We defer to future studies to assess the validity of this tribal placement.

Differential diagnosis. Scelianoma compacta [FZ2017], in addition to being extinct and recorded from Dominican amber, is differentiated from the extant, southwestern Puerto Rico-inhabiting Scelianoma elydimorpha sec. Franz and Girón (2009) by having a smaller size and less elongate body form, a more strongly foveate to lacunose dorsal sculpture on the pronotum and elytra, and a more slender rostrum, although the latter appears to have been laterally compressed by the process of fossilization. If our interpretation of the Terminalia of Scelianoma compacta [FZ2017] is valid, then then the posterior region of the median lobe is less arcuate in this species than in Scelianoma elydimorpha sec. Franz and Girón (2009).

Etymology

The epithet - "thick, firm, compact" ( Brown 1956) - refers both to the shorter, more compact habitus of Scelianoma compacta [FZ2017] in comparison to Scelianoma elydimorpha sec. Franz and Girón (2009), and to the 'compressing and distorting' effect that the fossilization process appears to have had on the specimen.

Distribution

Scelianoma compacta [FZ2017] is known only from the examined Dominican amber inclusion ("SEMC 339"; see Material) of the Burdigalian time period. The specific mine of origin for this inclusion is unknown.

Ecology

Unknown.