Christmas Beetles glossary
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About the glossary and key
This glossary was developed in reference to the Christmas Beetles lucid key. The key was design for people with varying degrees of prior knowledge of beetles, from the general enthusiast to research scientist. The terminology was kept simple but is supported by this glossary and illustrations.
A
Abdomen, abdominal = that part of the body posterior to thorax. The abdomen is strongly transversely segmented. The upperside, comprised of tergites, is often completely covered by the elytra but the last visible tergite, the pygidium, may protrude. The visible ventral segments are called abdominal ventrites.
Abdominal ventrites = visible ventral segments of the abdomen. In Anoplognathus six abdominal ventrites are visible on the underside with the first ventrite almost completely concealed by the hind coxae.
Acute = sharply angled, at less than 90 degrees.
Antenna (pl., antennae) = paired multi-segmented sense organ, arising from anterior margin of eye. In Anoplognathus, the antennae are 10 segmented, segments 2-7 are small and segments 8-10 are strongly laterally lobed and folded together as a club.
Anterior = at the front (Figures 6 and 7).
Antero-lateral = relating to the junction of the anterior and lateral regions.
Apex (pl. apices) = the tip or end of any structure, away from the base.
Arcuate = bow-like or arched.
Attenuate, attenuated = gradually tapering apically.
B
Base, basal = the nearest part of any structure to the main body. In beetles, the base of the body is at the junction of the pronotum and scutellum or elytra. Therefore the elytral base is the part nearest the pronotum and the pronotal base is the part nearest the elytra.
Bifid = forked; apically split.
Bilobed = with two lobes or projections
C
Canthus = narrow lobe of head cutting across anterior of eye.
Claw = one of two appendages at the end of each leg; usually sickle-shaped.
Clypeal apex = the tip of the clypeus (notes).
Clypeus, clypeal = the lower and anterior part of the head, between the frons and the anterior margin (Figure 1).
Concave = hollowed out; the interior of a sphere as opposed to the outer or convex surface.
Confluent = running together.
Confused = of striae; poor demarcation by nearby punctation or sculpture.
Contiguous = adjacent or touching.
Convergent = becoming closer apically.
Convex = the outer curved surface of a segment of a sphere; opposite to concave.
Coxa (pl. coxae) = the first segment of the leg, usually transverse or globular and inserted into the body (Figure 2).
Cuticle = the thick outer layer of the insect body.
D
Disc = the middle part of any large expansive structure, for example pronotum, elytron. Excludes the margins.
Dorsal = the upper surface of any structure (Figures 3 and 6).
E
Elytron, elytral (pl. elytra) = one of a pair of modified fore-wings of beetles, characteristically rigid, which fit over the abdomen when at rest, covering the hind wings (Figure 3).
Elytral suture = the line of junction of the elytra, when not being used for flight (Figure 3).
Emarginate = cut-out edge or margin.
Epipleuron (pl. epipleura) = the lateral edge of the elytron bent back on itself, defined dorsally by a prominent edge (Figure 6).
Explanate = spread out and flattened.
F
G
Genus (pl., genera) = a rank in taxonomy denoting a group of species considered to be more closely related to each other than to other species. The generic name is written in italics with a capital first letter and is part of the name of a species eg Anoplognathus concolor.
Glabrous = hairless, without pubescence.
H
Head = anterior part of the body, which contains most of the sensory organs (Figure 3).
Humerus, humeral (pl. humeri) = shoulder, basal swelling of the elytron (Figure 3) covering the attachment of the wing.
I
Impunctate = without punctures.
L
M
Margin = the area at the edge of any structure.
Mediolateral = at the middle of the sides.
Mesocoxa = middle coxa, basal segment of the mid leg.
Mesothorax = the second or middle thoracic segment, bearing the mid legs and elytra (Figure 4).
Mesoventrite = the median ventral sclerite of the mesothorax, formerly known as the mesosternum (Lawrence 1999). (Figure 5).
Metathorax = the third or posterior thoracic segment, bearing the hind legs and functional wings (Figure 4).
Metaventrite = median ventral sclerite of the metathorax; formerly known as the metasternum (Lawrence 1999) (Figure 5).
Metaventrite process = anterior projection of the metaventrite between the mid legs. In Anoplognathus the dorsal part of this process is partly formed from the mesoventrite (Figure 2).
Mucronate = describing a process with concave sides narrowing to an acute tip.
O
Obtuse = shallowly angled, with apical angle greater than 90 degrees.
P
Posterior = behind, opposite to anterior (Figures 6 and 7).
Preapical = just before the apex.
Process = a extension of a surface, of a margin, or of an appendage.
Prominence = an outgrowth or elevation above the surface
Pronotum, pronotal = large dorsal sclerite located between the head and the elytra, the dorsal part of the prothorax (Figure 3).
Prosternum = ventral sclerite of the prothorax (Figure 5).
Prothorax = the anterior thoracic segment, bearing the forelegs (Figure 4).
Pubescence = covering of hairs or setae.
Punctate = finely pitted, with punctures.
Puncture = a small circular pit in the surface of the cuticle.
Pygidium = the last visible dorsal segment of the abdomen, usually exposed beyond the apices of the elytra in Anoplognathus (Figure 3).
R
Recumbent = reclining, lying flat.
Reflexed = abruptly bent.
Rugose = sculptured so that the surface is irregularly raised, not smooth.
Rugulose = rugose but on a fine scale, surface appearing rough under high magnification.
S
Sclerite = any part of the body bounded by membranes or sutures.
Sclerotised = having a thickened, hardened cuticle.
Scutellum, scutellar = a small triangular dorsal sclerite of the mesothorax, wedged between the elytra and the pronotum. Internally, the elytra are attached to the scutellum (Figure 3).
Semicircular = literally half a circle, but here used for arcuate shapes with length more than half width.
Semiovate = arcuate in shape, with length less than half width.
Seriate = arranged or occurring in a series or in rows.
Seta (pl. setae) = a hair, an articulated hair-like projection on the cuticular surface.
Setose = covered with setae.
Sexual dimorphism = the difference in appearance between the two sexes of the same species
Shape = the form of an object depending on its outline or extenal surface.
Sinuate = S-shaped, usually in relation to margins or edges.
Spine = a thornlike process of the cuticle, not separated from it by a joint.
Spinule, spinulose = a small spine.
Spur = an articulated spine, usually in reference to the tibiae (Figure 2).
Stria (pl. striae) = row of punctures, from near the base almost to the apex of the elytra (Figure 3).
Subapical = located near the apex.
Suture = line of fusion of two distinct sclerites.
T
Tarsus, tarsal (pl. tarsi) = the apical part of the leg, attached to the end of the tibia, with 5 distinct segments in Anoplognathus (Figure 2).
Thorax, thoracic = the middle portion of the body, between the head and abdomen, consisting of three segments (prothorax, mesothorax, metathorax) (Figure 4). The legs and wings are attached to the thorax.
Tibia (pl. tibiae) = the fourth segment of the leg, between the femur and the tarsus (Figure 2).
Trochanter = the second segment of the leg, located between the coxa and femur.
Truncate = cut off squarely at the tip.
Tuft = a cluster of erect and elongate setae arising from a small area of cuticle.
V
Figure 1
Figure 1: Dorsal view of the head of Anoplognathus
Drawing © Kindi Smith, Australian Museum
Image: Kindi Smith© Australian Museum
Characters used in the key describing features of the head.
Locating the clypeus
The clypeus is the anterior part of the head visible in dorsal view, and is demarkated from the rest of the head by the frontoclypeal suture.
Clypeal shape
There are seven states
- semicircular, or almost so, length more than half width
- semiovate, much broader than long
- lateral margin distinctly rounded, but angled at junction with apex
- lateral margin straight
- lateral margin slightly concave
- lateral margin deeply concave
- lateral margin strongly sinuate, swollen at base and concave at apex
Locating the clypeal apex
The clypeus is the anterior part of the head visible in dorsal view, and is separated from the rest of the head by the frontoclypeal suture. The clypeal apex is the anterior margin, which is often reflexed.
Clypeal apex
There are two states
- not raised or slightly and not abruptly reflexed
- strongly and abruptly reflexed
Locating the clypeus
The clypeus is the anterior part of the head visible in dorsal view, and is demarkated from the rest of the head by the frontoclypeal suture.
Clypeal pubescence
This character refers to the dorsal part of the clypeus, excluding the anterior face of the upturned apex. Pubescence on the clypeus is often difficult to see, because the setae may be short and brown. It is best viewed laterally. Females often have the setae abraded.
There are two states:
- with moderately close erect setae
- without setae
Figure 2
© Australian Museum
Characters used in the Key describing ventral features:
Locating the metaventrite process
The metaventrite process is an anterior extension of the metaventrite, a plate between the mid and hind legs. The process is located between the midcoxae.
© Australian Museum
Metaventrite process colour
Colours are best examined in natural light. The main part of the process is considered here as the tip may be different.
There are three states
- dark green to black, often metallic
- pale green
- brown
Metaventrite process length
The length of the metaventrite process is measured relative to the basal segments, or coxae, of the fore and mid legs.
There are three states
- long (apex level with or exceeding hind margin of fore coxae)
- moderate (apex midway between mid and fore coxae)
- short (apex at anterior margin of mid coxae)
Metaventrite process shape
There are three states
- triangular with sharp (acute) tip, lateral margins straight or slightly convex. In this type the apex is rarely extended relative to the base
- elongate triangular with blunt (rounded) tip, lateral margins straight or slightly concave. In this type the apex is usually extended relative to the triangular base
- ovate, sides and apex strongly rounded
Form of sculpture
There are two states
- without a continuous basal band of dense fine punctures; these punctures absent or confined to sides and always absent from the middle of the ventrite. Punctures usually with recumbent or erect setae.
- with a contunous band of dense fine punctures at base. These punctures with short recument setae (often abraded).
Figure 3
© Australian Museum
Characters used in the Key describing dorsal features
- clypeal shape (see above)
- clypeal apex (see above)
- clypeal disc pubescence (see above)
Locating the pronotum
The pronotum is the dorsal part of the prothorax and is located between the head and elytra.
States of pronotal setae
There are three states
- setae present at least in the anterio-lateral corners, and sometimes across the anterior margin and along the lateral margins, but absent from the middle and posterior. The setae are white and erect or semi-erect
- setae present throughout. The setae are white and recumbent
- glabrous, setae absent
Locating the pronotal basal margin
The pronotum is the dorsal part of the prothorax and is located between the head and elytra. The basal margin is the posterior edge.
States of pronotal basal margin shape
The basal margin varies in shape where it abuts the scutellum.
There are three states:
- middle strongly bilobed, the lobes slightly angulate and separated by an arcuate excavation
- middle weakly bilobed, the lobes rounded and separated by a slight excavation
- with a single rounded or truncate lobe
Structure of pronotal basal margin
There are two states
- with a continuous raised border
- raised border absent at middle, which is smooth
Locating the elytral disc
The elytra are the two large sclerites posterior to the pronotum, which cover the wings. The elytral disc excludes the marginal area of each elytron.
States of elytral colour
The following states refer to the elytral disc, excluding the margins which may be different. Colours are best examined in natural light.
There are eight states
- pale green, non-metallic
- brownish-green, non-metallic
- strongly metallic green
- reddish-brown, non-metallic
- yellowish-brown, non-metallic
- yellowish- to reddish-brown with weak metallic reflection (metallic reflections may be green, gold, red, blue or violet)
- yellowish- to reddish-brown with pale yellowish-brown patches
- yellowish- to reddish-brown with darkly pigmented deep punctures, often coalescent, in striae
Locating the elytral disc
The elytra are the two large sclerites posterior to the pronotum, which cover the wings. The elytral disc excludes the marginal area of each elytron.
Elytral disc pubescence
There are two states
- setae absent or at most minute and sparse
- closely setose, the setae white and recumbent
Locating the elytral disc
The elytra are the two large sclerites posterior to the pronotum, which cover the wings. The elytral disc excludes the marginal area of each elytron.
Elytral texture
There are two states
- with convex unpunctured intervals between striae
- with flat punctured intervals between striae, or non-striate
Locating the elytral margin
The elytra are the two large sclerites posterior to the pronotum, which cover the wings. The elytral margin is found at the lateral edge of each elytron.
Elytral margin structure
There are two states
- mediolaterally explanate, or sinuate, so that part of margin in basal half is flatter and slightly projecting
- not medially expanded, without any expansion of the margin
Locating the elytral apices
The elytra are the two large sclerites posterior to the pronotum, which cover the wings.The subapical elytral swellings are raised areas located just before the apex of each elytron.
Elytral subapical swelling sculpture
The swellings are best examined from below, with the posterior of the animal raised.
There are two states
- smooth, without conspicuous short thick spines (spinules)
- with conspicuous short thick spines (spinules)
Locating the elytral apices
The elytra are the two large sclerites posterior to the pronotum, which cover the wings. The elytral apices are tips of each elytron, where they meet along the elytral suture.
Shape of elytral apices
There are two states
- apex of each elytron truncate or feebly rounded, so that apices are contiguous or almost so
- apex of each elytron rounded, curving inwards to suture, with angle of more than 130 degrees between each elyton at sutural apex
Locating the pygidium
The pygidium is the last visible dorsal segment of the abdomen and is the most posterior part of the body in dorsal view.
States of pygidial disc colour
The following states refer to the broad central area of the pygidium, excluding the margins which may be different. Colours are best examined in natural light.
There are five states
- metallic dark green
- brownish-green
- reddish-brown with weak metallic reflection (metallic reflections may be green, gold, red, blue or violet) (Figure 2C)
- dull reddish-brown (Figure 2D)
- dark brown (Figure 2E)
Locating the pygidium
The pygidium is the last visible dorsal segment of the abdomen and is the most posterior part of the body in dorsal view.
States of pygidial pubescence
The following states refer to the broad central area of the pygidium, excluding the margins which are often different.
There are three states:
- with close or dense erect or recumbent white setae
- glabrous or with sparse often brown erect setae, without uniform clothing of white setae
- with median strip of recumbent white setae and smooth almost glabrous patches on either side
Locating the pygidium
The pygidium is the last visible dorsal segment of the abdomen and is the most posterior part of the body in dorsal view.
States of pygidial disc texture
The following states refer to the broad central area of the pygidium, excluding the margins which are often different.
There are two states
- impunctate, or visibly punctured but with smooth surface between punctures
- rugulose, if punctures present these are usually obliterated by the rough surface
Locating the pygidial tuft
The pygidial tut is located at the tip of the pygidium, which is the most posterior part of the body in dorsal view.
States of development of pygidial tuft
There are two states
- apical tuft well-defined, by a dense group of long golden setae at tip of pygidium
- apical tuft absent or few apical setae present, not all arising from the pygidial apex
Figure 4
Figure 4: Lateral view of the thoracic segments of Anoplognathus
Image: Chris Reid and Kindi Smith© Australian Museum
Figure 5
Figure 5: Lateral view of the thoracic ventrites of Anoplognathus
Image: Chris Reid© Australian Museum
Characters used in the Key describing features of the thoracic ventrites
- colour of metaventrite process (see above)
- metaventrite process length (see above)
- metaventrite process shape (see above)
Figure 6
Figure 6: Lateral view of Anoplognathus
Image: Chris Reid© Australian Museum
Figure 7
Figure 7: Dorsal view of Anoplognathus narmarus showing viewing positions
Photo Figure 7 © Kindi Smith, Australian Museum
Image: Kindi Smith© Australian Museum
