Research Article |
Corresponding author: Courtney L. DiLorenzo ( clbris14@gmail.com ) Academic editor: Aaron Smith
© 2021 Courtney L. DiLorenzo, Gareth S. Powell, Andrew R. Cline, Joseph V. McHugh.
This is an open access article distributed under the terms of the CC0 Public Domain Dedication.
Citation:
DiLorenzo CL, Powell GS, Cline AR, McHugh JV (2021) Carpophiline-ID: an interactive matrix-based key to the carpophiline sap beetles (Coleoptera, Nitidulidae) of Eastern North America. ZooKeys 1028: 85-93. https://doi.org/10.3897/zookeys.1024.59467
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Carpophiline-ID is presented, a matrix-based LucidTM key, for the adult stage of the known species of Carpophilinae (Coleoptera: Nitidulidae) of North America, east of the Mississippi River. An overview of the features and technical specifications used to build the key is provided. The list of terminal taxa used in the key represents the most current regional account for Carpophilinae, a beetle subfamily of agricultural and ecological importance. The value of matrix-based, free access keys for the identification of difficult taxa is discussed.
Anatomy, characters, determinations, identification key, interactive key, matrix key, morphology, multi-entry key, taxonomy
Matrix-based keys, such as Lucid keys, are often superior to traditional dichotomous keys. They allow users to follow different paths to a determination, use particular subsets of characters, use multi-state and non-traditional characters (e.g., biological, geographical, phenological, and genetic data), and allow creators to incorporate extensive supporting graphics to aid in identification (
Sap beetles are represented by ~ 4,500 species in ~ 350 genera worldwide (
Several species of Carpophilinae, especially those in Nitops Murray, feed on pollen as adults. Ongoing research continues to determine pollination efficacy by these beetles, especially for plants in the genus Annona L. (Magnoliales: Annonaceae) (
Historical dichotomous keys to Carpophilinae of the USA are available (e.g.,
This key covers all Carpophilinae known to occur east of the Mississippi River in the USA and east of 90° longitude in Canada, including all four genera and 21 of the 34 species currently known to occur in America north of Mexico.
Caplothorax lugubris (Murray, 1864); Caplothorax melanopterus (Erichson, 1843); Caplothorax sayi (Parsons, 1943); Carpophilus antiquus Melsheimer, 1844; Carpophilus brachypterus (Say, 1825); Carpophilus corticinus Erichson, 1843; Carpophilus dimidiatus (Fabricius, 1792); Carpophilus discoideus (LeConte, 1858); Carpophilus fumatus Boheman, 1851; Carpophilus hemipterus (Linnaeus, 1758); Carpophilus marginatus Erichson, 1843; Carpophilus marginellus Motschulsky, 1858; Carpophilus mutilatus Erichson, 1843; Carpophilus nepos Murray, 1864; Carpophilus pilosellus Motschulsky, 1858; Carpophilus tempestivus Erichson, 1843; Nitops craigheadi (Dobson, 1972); Nitops floralis (Erichson, 1843); Nitops ophthalmicus (Murray, 1864); Nitops pallipennis (Say, 1823); Urophorus humeralis (Fabricius, 1798).
For each species represented in the key, there is a minimum of one male dorsal and one male ventral habitus photograph. All specimens imaged were determined by the second and third authors (GSP & ARC). Photographs illustrating each character and all of the various states are provided in the key. All species-specific character images are included in the appropriate Species Fact Sheet, along with corresponding dorsal and ventral habitus images. These Species Fact Sheets can be accessed by hyperlinks provided for each species in the Entities section of the key.
Diagnostic characters in the key were derived from existing literature (
The data matrix includes 41 anatomical, distributional, and ecological characters. These characters appear in the Features section, each with two to five possible character states. All features refer to either external adult anatomical structures that can be easily seen with a stereomicroscope, ecological details, or the locality where the specimen was collected. For length and ratio features, numeric ranges were derived from the literature (
GENERAL: sex (male/female); length (mm); host association (cactus flowers/other hosts or habitats); geographic distribution (Northeast/Mid-Atlantic/Great Lakes Region/Mississippi Valley/Southeast); body convexity in lateral view (flattened/convex); body surface overall appearance (glossy/dull).
ANTENNA: antennal club shape (round/oval); antennomere coloration (abruptly darker at club/gradually darker towards club/unicolorous throughout).
EYE: ratio of eye width at widest point: intraocular distance at narrowest point (1:3 or less/between 1:4 and 1:9/1:10 or more).
PRONOTUM: pronotal disc setation length (long/not distinctly long); pronotal disc punctation density (dense/sparse/not conspicuously dense or sparse); pronotum coloration (black/dark brown/medium brown, light brown, or orange); pronotum posterior angles (broadly rounded, no distinct ‘corner’ created/squared due to extra anterior deflexion of lateral margin/nearly forming a 90-degree angle, not broadly rounded or squared off).
ELYTRA: elytral coloration (bearing pattern or markings/unicolorous); elytral color pattern (conspicuous yellowish humeral and apical patches/light humeral patches only/darker coloration near scutellum and apex/darker coloration near scutellum only/dark coloration near apex only); elytral coloration unicolorous (unicolorous and distinctly darker than pronotum and tergites/unicolorous and distinctly lighter than pronotum and tergites/unicolorous, similar to pronotum and tergites); shape of elytra apex (straight, squarely truncate/rounded, arching posteriorly).
PROTHORAX: ratio of prosternal process width at narrowest point between coxae to width at widest point posterior to coxae (less than 1:2/greater than 1:2); median longitudinal carina on prosternal process (present/absent).
MESOTHORAX: posterior rim of mesocoxal cavities (crenulate, not forming axillary space/smooth, not forming axillary space/smooth, forming small axillary space extending ~ ¼ posteriad along metepisternal suture/smooth, forming large axillary space extending ½ posteriad along metepisternal suture); mesosternal median longitudinal ridge (present/absent); mesosternal anterior impunctate edge along median longitudinal ridge (present/absent, bearing longitudinal ridge only); mesosternal impunctate area near center (present/absent, punctate throughout).
METATHORAX: male metathoracic tibial shape (abruptly dilated apically/gradually dilated apically); male metathoracic femur (bearing small toothlike projection on inner margin near trochanter/lacking a tooth-like projection near trochanter); metathoracic tibial spines along posterior margin (present, distinct/absent, not distinct).
PYGIDIUM: male pygidial lateral margin shape (visibly constricted/not constricted); male supplementary segment visibility in dorsal view (visible/not visible); female pygidium bearing large oval depression with vague anterior margin at apex (present/absent); female pygidium apical flexion (deflexed ventrally/upturned medially/not flexed upward or downward); female pygidium bearing weak median longitudinal ridge (present/absent); female pygidium bearing grooves along lateral margins (present/absent); female pygidium lateral margin shape (visibly constricted/not constricted, straight); female pygidium apical margin shape (pointed, acute/broadly rounded or truncated); female pygidial disc setation length (short, at most just able to reach base of nearest seta/medium to long, clearly able to overlap adjacent setae); female pygidial disc setal density (dense/sparse); female hypopygidium setation length (apical setae longer than other setae/apical setae not distinctly different in length from other setae).
ABDOMINAL VENTRITES: male 4th ventrite setation (bearing many distinctly elongate setae medially at posterior margin/without any distinctly elongate setae); male 5th ventrite setation compared to density anterior to supplementary segment (less dense or absent/not distinctly different density); male 5th ventrite depression, shape and location (single undivided median circular depression with coarse punctation anterior to supplementary segment/single undivided median circular depression anterior to supplementary segment/single median rounded depression divided by horizontal ridge anterior to supplementary segment/pair of elongate oval depressions lateral and anterior to supplementary segment/without any depressed area anterior to supplementary segment); male setation on supplementary segment (setose with two distinctly longer setae/setae of approximately equal length); female hypopygidium setation length (apical setae longer than other setae/apical setae not distinctly different in length from other setae).
Application: Lucid Builder 3.5 (https://www.lucidcentral.org, website provides technical specifications and features list)
Key Version: 1.0
Requirements for use: Java-enabled browser and internet connection
License for use of the key: Creative Commons Attribution License 4.0 (CC-BY), which permits unrestricted use, distribution, reproduction, and editing, provided the original author and source are credited.
Web location: https://site.caes.uga.edu/carpophiline-id/
The data underpinning the Lucid Key (Lucid Key files) reported in this paper are deposited in the Dryad Data Repository at https://doi.org/10.5061/dryad.h44j0zphq
https://site.caes.uga.edu/carpophiline-id/taxon-fact-sheets/
All 21 species represented as entities in the key are figured with dorsal habitus, ventral habitus, and diagnostic character images. Each species fact sheet includes a diagnosis and summaries of the known biology and distribution, as well as references. Within the interactive key, these pages can be accessed through hyperlinks provided within each species entry.
https://site.caes.uga.edu/carpophiline-id/resources/
This section provides an anatomical atlas (also available within the key), a glossary of terminology, and diagnoses for the beetle family Nitidulidae and the subfamily Carpophilinae. The anatomical atlas illustrates all of the structures mentioned in the key on a dorsal and/or ventral habitus image of a male specimen of Carpophilus marginellus. The glossary provides definitions of terms used in the key. Definitions were derived from
https://site.caes.uga.edu/carpophiline-id/references/
This section provides a list of useful references about Carpophilinae, building interactive keys, and making species fact sheets.
Since multi-access keys enable users to skip sex-specific, hard-to-view, and rarely available characters, additional, more difficult diagnostic features (e.g., male genitalic anatomy, features on immature stages, genetic markers, etc.) will be added as they become available. A comprehensive taxonomic revision of the Carpophilinae of North America is currently being conducted (by GSP). Upon completion, newly published information may be incorporated into the data matrix and species fact sheets to update the interactive key.
This key provides a user-friendly tool that will make species-level identifications of Carpophilinae possible for specialists and non-specialists. Additions and updates will be possible as new characters become available and taxonomic changes occur within the group. The key may also be expanded to include newly discovered species, or to extend geographic distributions to create a more inclusive tool.
This work was completed in partial fulfillment of M.Sc. degree requirements at the University of Georgia for author CLB. The senior author thanks the Department of Entomology, her Advisory Committee members (W.G. Hudson, B.R. Blaauw, and J.V. McHugh), and members of the McHugh lab (B. Hounkpati, T. McElrath, C. Fair, K. Murray, B. Clark, and T. Sheehan) for their support and feedback. We thank E.R. Hoebeke (