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

Femur, femoral (pl. femora) = the third segment of the leg, between the trochanter and the tibia (Figure 2).

Foreleg = anterior leg (Figure 2).

Frons = portion of the head, between the eyes and the clypeus (Figure 1).

Frontoclypeal suture = the line of junction of the frons and the clypeus (Figure 1).

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

Lamellate = like plates, in reference to the antennal club segments.

Lateral = at the side, as distinct from anterior and posterior (Figure 7).

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

Venter, ventral = the under surface of any structure (Figure 6)

Ventrite = any visible ventral sclerite, used in reference to ventral segments of the thorax and abdomen.

Figure 1

Dorsal view of the head of Anoplognathus — 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

Figure 2: Ventral view of Anoplognathus Image: Chris Reid
© 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.

Figure 1. Ventral view of Anoplognathus Image: Kindi Smith
© 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

Dorsal view of Anoplognathus narmarus — Figure 3: dorsal view of Anoplognathus narmarus Image: Kindi Smith
© 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