glaresidae, archaeopteryx of the scarabaeoidea (coleoptera)

Glaresidae, archaeopteryx of the Scarabaeoidea (Coleoptera)

C . H . SCHOLTZ, D . J. B R O W N E and J . K U K A L O V A - P E C K " Department of Entomology. University of Pretoria, South Africa, and *Department of Earth Sciences, Carleton University, Ottawa, Canada

Abstract. Evidence is presented that Glaresidae a re the most primitive livinl scarabaeoid group and as such represent the sister group of the rest of tht Scarabaeoidea. This is based on a review of the states of seventy-two morphologica characters. The plesiomorphic states of many characters are unique to the Glaresidae or are shared with other primitive scarabaeoids; seven may be synapomorphic with other groups and two are autapomorphic for the family.

Introduction

There has been considerable speculation over the years about the nature of the ancestral scarabaeoid or, in the absence of evidence to support such a hypothesized animal, what is the most primitive extant scarabaepid. Crowson (1955. 1981) proposed that ancestral scarabaedds were small convex beetles adapted for burrowing in sail (something like modern-day Glaresidae, Ochodaeidae 'or Bolbocer- aticlae) where they probably fed on subterraFan fungi. He treated the Lucanidae, followed by Trogidad, as the most primitive living scarabaeoids. lablokoff-Khnzonan (1977) hypothesized that the ancestral scarabaeoid was large and pleocomid-like and occurred in rotting.wood, as do, for example, Passalidae, which he considered among the most primitive scarabaeoids. Howden (1952), based on a partial phylogenetic analysis of some major groups of Scarabaeoidea, implied that the Passalidae and Lucanidae were the most primitive extant scarabaeoids. Paulian (1988 and in many of his earlier works) treated Lucanidae and Passalidae as most primitive. All of the above authors considered Glaresis and its relatives (eithee explicitly or implicity) as members of the Trogidae, because that was their existing status. Although this system was followed by students of the Scarabaeoidea it was usually with misgiving, and doubts about the placement of Claresis in the Trogidae were expressed verbally by Crowson, Howden and Paulian (Scholtz, 1986). It was removed from the Trogidae by Scholtz (1986) after phylogenetic analysis of the elements of the Trogidae, but he offered no substantiated alternative to its placement in the Scarabaeoidea. Scholtz er al. (1987)

Correspondencc: Dr C. H. Scholtz. Departmcnt of Entomology. University of Prctoria. Pretoria 0002, South Africa, or Dr Jarmila Kukalova-Peck, Department of Earth Sciences, Carleton Univcr- sity. Ottawa. Canada.

reassessed the position of Glaresis and concluded that it i: not clearly related to any other scarabaeoid group, anc that it is primitive and lies close to the basic evolutionar) stock from which the Scarabaeoidea evolved. Because G1aresi.s shows no affinities to any other group, they erectea a family to accommodate it.

Since the study by Scholtz et ul. (1Y87) a large body of morphological evidence has accumulated to support the assumption that the Glaresidae are the most primitive living scarabaeoids. We present the evidence in this paper and propose that the Glaresidae are the sister group of the rest of the Scarabaeoidea.

Because Glaresidae were claimed in previous studies to be primitive in many respects, it was the aim of this study to place Glaresidae relative to all other scarabaeoid families in a probable phylogenetic hierarchy, and not to group all the taxa on the basis of shared apomorphic characters. Consequently, a comprehensive cladistic analysis of all characters was beyond the scope of this study but will be done in future. However, all of the characters considered here have been phylogenetically assessed in the past or were assessed for the purposes of this study, and we are confident that our interpretation of the polarity of most of the character states is the most parsimonious one. The few problems of interpretation we did encounter are with apomorphic characters apparently shared between Glaresidae and other taxa where it was not possible to state unequivocally whether the characters are homologous or were independently derived in the respective taxa.

Some of the characters dealt with have been considered in previous studies (Scholtz et al . , 1987), but all have been re-assessed in the light of subsequent studies in the Scarabaeoidea (Caveney & Scholtz. 193; d'Hotman & Scholtz, 1990: Nel 9( Scholtz, 1990; Nikolajev, 1992: Scholtz, 19YO: Scholtz ef al., 1988) or Coleoptera (KukalovC Peck & Lawrence, 1993). The rest of the characters, which

260 C. H. Suhoitz. D. J. Browrir arid J. K ~ i I i u I ~ i ~ i i - P r c k

Fig. 1. Glarcsis impressicollis Petrovitz. dorsal habitus.

relate mainly to the wings, wing articulation and the wing base have never been considered before in the Scara- baeoidea. Consequently, these structures are dealt with in more detail in this report than are any of the other characters.

Glaresidae (Fig. 1) are a small, virtually cosmopolitan (absent in Australia), monotypic family which is represented by about fifty uniform species worldwide. They are small (2.5-6.0mm long), light buff to dark brown. Most species occur in sandy areas in arid regions where adults may be locally abundant; otherwise very little is known of their biology. Larvae are unknown.

Outgroup for the Scarabaeoidea

The monophyly of the Scarabaeoidea remains undisputed (Lawrence & Britton, 1991) but the question of a possible

outgroup for the Scarabaeoidea has not been resolved (see Scholtz. 1990). The groups most favoured are the Dascilloidea, or various members of the Staphyliniformia. Information presented below lends some support to the latter group as the possible outgroup but other evidence refutes it, as does it for the Dascilloidea as the outgroup.

Jeanne1 & Paulian (1944) proposed a classification of the Polyphaga based on the degree of regression of the basal abdominal sternites. They divided the Polyphaga into two groups. Haplogastra and Heterogastra (=Symphiogastra). Haplogastra (first proposed by Kolbe, 1908; Hydrophi- loidea, Staphylinoidea, Histeroidea and Scarabaeoidea) are characterized by having sternite 2 visible only as a lateral rudiment and pleural sclerite, whereas in Heterogastra (rest of the Polyphaga) it is usually complete though membranous. Although this division has fallen into disuse, general consensus of opinion among coleopterists recog- nizes some relationship between adults of the super-families

in the Haplogastra groups (Crowson, 1955: Paulian. 1988; Lawrence & Britton. 19'91). but it is very difficult to substantiate this on larval characters. The general habitus of scarabaeoid larvae, the detailed structure of head capsule and mouthparts, and the cribriform spiracles, are without parallel in the other Haplogastra (Crowson, 1955). Furthermore, no known scarabaeoid larva shows the slightest vestige of thc characteristic articulated urogomphi which distinguish haplogastran from other polyphagan larvae. Many scarabaeoid larvae, however, are similar to those of some Dascilloidea (Heterogastra) in that they are large grub-like forms with a large head, long antennae, uibriform spiracles, similarly robust mandibles with well- developed mola and accessory ventral process, separate galea and lacinia, and complex epipharynx and hypopharynx (Lawrence, 199 1). However, dascilloids differ from all scarabaeoids in having distinct tergal plates, labrum and clypeus at least partly fused together and to the frons, a very short epicranial stem, an articulated process beneath the mandibular retinaculum, heavily sclerotized comb-like structures on both epipharynx and hypopharynx, a strongly bilobed ligula, a more or less reduced tenth segment without anal pads, and (usually) urogomphi on tergum 5, (Lawrence, 1991).

The supposedly homologous intersegmentalin associated with mesothoracic spiracles in adult Dascillidae and Scarabaeoidea (Ritcher, 19hYb); similarity in exo- cone ommatidium structure in dascilloids and Passalidae (Caveney, 1986); similarity in trilobe male genitalia with a well-defined genital capsule in some dascilloids and various primitive scarabaeoids (e.g. Glaresidae), and close similarity between Dascilloidea and Pleocorna and Diphyl- lostoma in the longitudinal division of the median lobe of the aedeagus (d'Hotman Jt Scholtz, l W ) : mouthparts (Nel & Scholtz, IWO); as well as open procoxal cavities which are similar in Dasciflus and Pleocomidae, lend support to the hypothesis that Dascilloidea are the outgroup of the Scarabaeoidea. Crowson (1981) and Scholtz (1990) have favoured this possibility. However, Lawrence & Newton (1982) and Lawrence & Britton (1991) reject this hypothesis, claiming similarities between dascillid and scarabaeoid larvae are either plesiomorphic or associated with soil-dwelling habits. They state that adult dascilloids share many more important features (such as the complex prothoracic interlocking device) with elateriform taxa such as Callirhipidae and Ptilodactylidae than with scarabaeoids. Evidence presented recently by Kukalova-Peck & Lawrence (1993) o n the evolution of the hindwing in Coleoptera lends further strong support to a Haplogastra- Scarabaeoidea relationship and refutes close relationship between the latter and the Dascilloidea.

Characters studied

All of the characters discussed below have been examined or re-examined by ourselves or colleagues in a wide variety of scarabaeoid groups and all are assumed to be of phylogenetic importance. They are numbered and placed in

square brackets in the text, and listed in Table 1. Some of the characters first studied in earlier works were reviewed and reassessed by Scholtz ( 1990), but many of the character suites discussed below have not been dealt with before in the Scarabaeoidea. Wing characters i n the Scarabaeoidea were dealt with in detail in a recent study (Browne, 1993) as part of a broad-based, detailed phylogenetic study of all the major scarabaeoid groups. The wing study is a sequel to a similar one on the Coleoptera as a whole (Kukalovi- Peck s( Lawrence, 1993). The system of wing articulation and wing base terminology in this paper follows that of Browne & Scholtz (1994). Derived characters which are apparently shared between Glaresidae and other groups are ti-eated in more detail than are the others because shared apomorphic characters contain more cladistic information than do plesiomorphic characters. Scholtz's (1990) classification of the Scarabaeoidea is followed except that Bolboceratidae are here treated as a separate family to the Geotrupidae (as opposed to a subfamily of the Geotrupidae) because of increasing evidence that the Geotrupidae as presently constituted arc polyphyletic.

Eleven joinrs are traditionally assumed to be the ancestral condition in the Scarabaeoidea [ 11 [and Colcoptera] and any reduction in number is thought to be derived (see Crowson, 1981). Eleven-jointed antennae are found in the Upper Jurassic fossil Ceofrupoidrs, as well as the primitive families Bolboceratidae, Geotrupidne (all except Tauro- cerastinae), Pleocomidae and some Glaphyridae (although there is doubt about this, see Scholtz, 1990). as well as in some members of the highly-derived Melolonthinae. All other primitive families (with only isolated exceptions in Ochodaeidae and Ceratocanthidae), including Glaresidae, have 10-jointed antennae, as do many higher scarabaeoids. Consequently. it is difficult to avoid concluding that in at least some cases (notably the Melolonthinae) secondary division of segments may have led to an increase in number. If this is so, a similar increase in number may have occurred i n other groups, and if commonality is applied (although admittedly not always a reliable state), it would appear that 10-jointed antennae may actually be the ancestral situation in the Scarabaeoidea and an increase or decrease in number is derived. Alternatively, if 11 is the ancestral number, reduction to 10 or fewer segments may have occurred independently in various groups. Similar reductions have occurred within other groups (e.g. 10 segments in Taurocerastinae as opposed to 11 segments in all other groups in the Geotrupidae; reduction to 9 segments in some ochdaeid genera; and multiple reductions in Scarabaeinae, Melolonthinae and others). A 3-Jointed club [2], such as is found in many primitive and some derived groups, appears to the the ancestral condition.

Eye: carifhics (Fig. 3 )

An ocular (genal) canthus [ 3 ] is present in most scarabaeoids, including Glaresidae. I t is absent in all members

262 C. H. Scholtz, D. 1. Browrie arid J . Kukalot,u-Pcck

Table 1. Characters of phylogcnctic iinportancc in the Scara- bacoidca, relative to the Glarcsidac. 0 = plcsiomorphic stiltc: 1+ = one or more aprnorphic statcs. Scc tcxt for discussion of charactcrs.

Character Glarcstdac Othcr rcambacoicl tam

1 0 0 - I + 2 0 0- I + 3 1 0 - I 4 0 0- I 5 1 0- 1 6 0 0- I + 7 0 0- 1+ X 0 0 - 1+ 9 0 0- It 10 0 0- 1+ 1 1 0 0- I + 12 0 0- I + 13 0 0- 1+ 14 0 0 - 1+ 15 1 0 - 1+ Ih 1 0 - 1t 17 0 0 - 1 t 1X 1 0 - I t!, I 0 - 1 20 0 0 - I 21 0 1t 22 0 1 + 23 0 I + 24 0 I + 25 0 I + 2h 0 0 - I 27 1 0 28 I 0 - I + 29 0 I + 30 I 0 31 1) 0- I+ 32 ( J 0- I + 33 0 0 - I + 34 0 I+ 35 0 I + 36 0 1+ 37 0 I + 38 0 1+ 39 0 1+ 40 0 1+ 41 0 0- I + 42 0 0- 1 43 0 0 - I + U 0 0 - 1+ 45 0 0 - 1 + 46 0 0- 1+ 47 0 0 - I + '48 0 0 - 1+ 49 0 0- I + 50 0 0 - I + S l 0 0- I + 52 0 0 - 1+ 53 0 0 - I + 54 0 0 - I + 55 I) 0 - I + 56 0 1+ 57 0 I +

Table 1. (cotrfiriired)

Character Glaresidac Othcr scarabacoid t a w

58 59 h( ) hl 62 63 fA 65 hh 67 68 6') 713 71 72

0 0 0 0

0 0 0 0 0 0 0 0 0 0

r)

1+ 1 + I + 0- I + 0 - I + 0 - I + 0 - 1+ 0- 1+ 0 - I+ 0 - I + 0- I + 0 - I + 1 ) - I + 0 - I + 1 +

of a few primitive groups (Diphyllostomatidae, Trogidae, Ochodaeidae) or just in some members of primitive groups (Lucanidae). Its absence is generally assumed to be the primitive condition. Although the presence of a canthus appears to be a derived character. the origins of the structures in the various groups are different. Clearly the evolutionary pressure to develop a structure to protect the eye during burrowing was strong, but differcnt lincages solved the problem in different ways. In somc tnxa the canthus intrudes dorsally into the eye and in others vcn- trally, so the structure appears to be polyphyletic in origin.

Eye: ornmatidiiirn s t r i ~ c t i m (Fig. 4)

The compound eye is strongly faceted. with basic eucone ommatidia [4]. The eucone found in Glaresidae is the ancestral type i n the Scarabaeoiclea (Caveney Sr Scholtz, 1993). Eucone ommatidia are found i n many primitive and derived groups but they differ slightly from those in Glaresidae.

Mouthparts: marrdihles (Fig. 5 )

Primitively the mandible [ 5 ] has a sclerotized basalis. and apicalis which usually ends in a single tooth, and is without a prostheca and true molar area. This type is found in Lucanidae, Passalidae and, in greatly reduced form, in Diphyllostomatidae and Pleocomidae.

A more derived type has a definite molar lobe and prostheca. This type may be divided further into: (i) one with a simple but distinct molar lobe and prostheca as in Glaresidae, Ochodaeidae, Bolboceratidae and Hybosoridae; (ii) one with a mesa1 brush (or developed prostheca). a conjunctive, and a well-developed/ridged molar lobe (Geotrupidae), and occasionally a mycangium (all Ceratocanthidae and some derived genera in various higher groups); (iii) one in which the molar surfaces are

2 a 3 b Figs 2-3. Gltrresis itnprcssicollis. antenna and hcad. 2. 10-scgmcntcd antcnna with 3-scgmcntcd club. 3. Hcad in ( a ) dorsal and (b) latcral. vicw, illustrating ocular canthus.

Fig. 4. Phasc-contrast light micrograph of a section through thc cyc of Gluresis itnpressicollis illustrating a primitivc euconc cyc.

5 6 7 8 Figs 5-8. Gliresis itnpressicollis. mouthparts. 5. Mandiblcs. h. Maxilla. 7. Labium and tcntorium. 8. Epipharnyx.

264 C. H . Scholti, D . J . Browlle utid J. Kiikuh-r i -Peck

well developed. usually coarsely ridged and mostly abym- metrical (Rutelinae, Meloionthinae, Trichiinae).

The most derived type is found in the Scarabaeinae. The basalis is strongly sclerotized and is characterized by a receptaculum and asymmetrical molar lobes. The stiff membranous distal portion is the apicalis and consists of a lateral sclerite, a comb-like prostheca and a distinct conjunctive. Setae on the apicalis may be arranged into tufts, the so-called combs (Nel & Scholtz, 1YYO).

h1oirthpart.s: muxillur (Fig. 6)

Maxillary structure varies greatly within the Scara- baeoidea (Nel & Scholtz, 1YYO). Most of the variation is found in the number of palp joints IS] . whether a lacinia is present or absent [ 7 ] . the number of lacinial teeth [X I , whether the galea is bi- or monolobed and dentate o r not 191, and whether articulatory and maxacorial scleritcs are present or absent [ 101. Glaresidae have the plesiomorphic condition of all of these characters.

Mourhpurts: luhitirn (Fig. 7)

The labial characters with most phylogenetic information are the number of palp joints [ l l] , whether the mentum is bi- or monolobed [12], whether the prementum is separate from or fused to the mentum [ 131. and whether the ligula is bilobed or not [ 141 (Nel & Scholtz, 1990). The glaresid labium is of the most basic type, with regard to all labial characters.

Terztorium (Fig. 7 )

Two distinct types of tentoria [LS] are found in thc Scarabaeoidea: a primitive, 'invaginated tentorium'. with invaginations in the anterior or posterior margins, is found only in the Lucanidae; and a derived, foraminated tentorium. The latter can be subdivided into a less-derived single-foramen-type and a more derived two-foramen- type. The single-foramen-type has only an anterior foramen and a median tentorial bridge, whereas the two- foramen-type has two foramina in the tentorial bridge, a large posterior one and a smaller anterior one. The single-foramen-type is most commonly encountered in primitive Scarabaeoidea such as Glaresidae, Trogidae, Ochodaeidae, Hybosoridae and Geotrupidae, as well as in highly-derived groups such as some Cetoniinae, Melolonthinae, Rutelinae and Dynastinae. The two- foramen-type tentorium may also have secondarily derived additional tentonal arms arising from the posterior tentorial pits such as is found in some Pleocomidae, Ochodaeidae and most Meloionthinae. The most derived two-foramen- type tentorium is found in some Scarabaeinae. In this type an anterior bridge bears two shorts arms pointing anteriorly and their bases may be fused to form an anterior secondary bridge (Nel & Scholtz, 1990).

A primitive intermandibular projection, which is ;I median extension of the clypeus, or fused clypeus and frons, and lies between the mandibular bases, is present in Lucanidae. Diphyllostomatidae and Pleocomidae.

A primitive true epipharynx [16], which may be symmetrical or asymmetrical and which possesses single tormae, lateral combs present as setal patches, and a variable apical margin, is present in most of the remaining scarabaeoid groups with the exception of the Scarabaeinae.

A derived epipharynx is membranous and usually has double lateral tormal processes. and lateral combs of which the setae are arranged in one or two definite rows. This type occurs only in t h e Scarabaeinae (Nel & Scholtz, IYYO) .

Legs (Figs Y-10)

All species of Glaresidae have broad spatulate legs [ 171 which are clearly well adapted for digging. Since the ancestral scarabaeoid was very likely a fossorinl bcetle. as are most extant species, thc condition in Glarcsidac probably rcprcsents t h e primitive state.

Trochutztin

Exposed protrochantin [ 181 is the primitive condition i n the Scarabaeoidea and is found only in Diphyllostomutidac and Pleocomidae. All other scarabaeoids, including Glarc- sidae, have the protrochantin concealed. There appears to be little doubt that the condition in glaresids and other scarabaeoids is more derived than in the above two taxa. but there is no supporting evidence to confirm thztt the conditions in the rest of the taxa are not independently derived, at least in some lineages.

Procoxar

Primitively open procoxal cavities [ LY] are only known from Pleocomidae. In the derived condition, found in all other scarabaeoids including Glaresidae, they are closed by the meeting of the proepimeron and the prosternal process.

Mesocoxa e

Mesocoxal cavities [20] are primitively open laterally in Glaresidae and several other scarabaeoid groups. They are closed by the meeting of the meso- and metasterna in Trogidae and Passalidae.

iMesothoracic spiracles

Conclusions about evolutionary trends in the structure of mesothoracic spiracles and adjacent sclerites (inter-

a b

9

C

10 Figs 9-10. GIciresis irnpressicollis. legs and mcsothorau. 9. (a) Fore leg, (b) Middle leg. (c) Hind leg. illustrating fossorial adaptations. 10. Mctathorax, illustrating mcsotibial fossae (arrowcd) into which mcsotibiac arc rctractcd during digging.

segmentalia) in the Scarabaeoidea can be drawn (Ritcher, 196%). The trends in the evolutionary development of the spiracles are towards a porous or solid filter apparatus from separate atrial spines [21], and towards a reduction in the size of the spiracular opening [22]. Those in the intersegmentalia [23] are towards a reduction in number, from several sclerites on each side to a median, setifcrous sclerite. Glaresidae are primitive in all respects.

Hiridwing vrrzurion (Figs 1 1 - IS)

Evolutionary succession of venation characters within the hydrophiloid lineage (=Haplogastra) is relatively easy to estimate, because the most primitive superfamily Hydrophiloidea is very close to the groundplan of the Polyphaga (Kukalovi-Peck Sr Lawrence, 1993). Hydro- philoidea have a primitive eyelet-like radial cell, but it is weakened proximally by the obliteration of the base of RA3 + 4 with the anterior margin (both modifications are typical for the lineage): RA4 and RP1 are fused together, and API + 2 is lost (two autapomorphies). RA4 and RPI are not fused together, and API + 2 is not lost in the groundplan of the hydrophiloid lineage. Thus the most primitive scarabaeoid venation characters are expected to be well preserved (=not reduced) and more or less ‘hydrophiloid-like’ (Fig. 1 I ) , as follows: a primitive radial cell is almost eyelet-like or at least broadly triangular; a primitive cross-vein r4 is well recognizable; all primitive RA and RP branches (RA3, RA4, RPI, RP2, RP3 + 4) are present and long: branches RA4 and RP1, after approaching one another, run in parallel and do not fuse (as in the Polyphaga groundplan, Fig. 17a); and the branches of M, Cu and A (MPI + 2 , MP3, MP4, CuA, short CUP-, AA1 + 2. AA3 + 4, AP3 -I- 4, J A l + 2 , JP3 + 4) are pri- mi tivel y present .

Scarabaeoids have a highly specialized folding of the radial and medial loop accompanied by extensive crimping, lack of radial hinge, modified and narrowed radial and

medial loops, and a prominent secondary sclerotization between and beyond the loops. These characters and the central folding pattern probably have the capacity to show their own succession of characters, which could be instrumental for elucidating the phylogeny of Scarabaeoidea.

Scarabaeoidea are characterized by the following features of the hindwing (Figs 13- 18): (1) radial cell deforms from the eyelet-like, proximally weakened form and becomes distally strengthened and progressively more ‘open’, narrow, oriented at an acute angle with the radial har and folding on itself (Figs 17d-i); (2) radial hinge is rcplaced by a densely crimped radial bend (Figs 17g-I); (3) cross- vein r4, which co-ordinates simultaneous curving of the radial and medial loop, is shifted proximally (Figs 17d-i); (4) r4 becomes curved distad so that it ends on RP1 + 2 instead of RP (Figs 17g-i); (5) r4 progressively disappears and is replaced by a stiffened membrane (Fig. 17i); (6) r3 is lo’st (Figs 17c-i); (7) cross-vein rp-mp:! (part of the medial hook, Figs 11, 17a-b) is completely reduced (Figs 17c-i); (8) the tip of RP and the tip of the medial bar are fused together, separated by a deeply incised suture (Figs 17c-i): (9) RP and medial bar run close to one another (Figs 17c-i); (10) RP3 -t- 4 shifts posteriorly to meet medial spur (Figs 17c-i); (11) CuA3 + 4 is reduced (Figs IXb-f); (12) AAI + 2 is spike-like (Figs 18c-e).

Characters 2 , 4 and 5 occur only in Scarabaeoidea (as autapomorphies) (Figs 13-16): characters 1, 3 and 12 are found in Scarabaeoidea and Histeroidea (as synapomorphies) (Figs 12, 17d-i) and characters 6, 7, 8, 9, 10 and 11 occur in Scarabaeoidea, Histeroidea and Staphy- linoidea (as synapomorphies) (Figs 17- 18).

Radiul cell

The ancestral condition in the hydrophiloid lineage (=Haplogastra) is one in which the radial cell forms a proximally weakened eyelet outlined by RA3 + 4. In Gluresis the radial cell [24] still resembles il primitive

266 C. H. Scholti. D. J. Browtre arid J. Kuka1or.a-Peck

MP4 RA4

11

Pseudohy robiits

12 a

Sphaerites

b Necrophilus

13

GIaresis

Figs 11 -13. Venatiooal systems of the hydrophiloid lineage (=Haplogastra). 11. closc to the Polyphaga groundplan. Hydrophiloidcu: Hydrophilidae: Pseudohydrobius sp. Length 5.5 mm. 12a. Primitive Histeroidea: Sphaeriridae: Sphaerites glabrarus. Length 8 mm. 12b. Primitive Staphylinoidca: Argytidae: Piecroplrihs Izydrophiloides. Length 17mm. 13 Primitive Scarabaeoidca: Glarcsidac: Glaresis w&fue. Length 6 mm. Originals: Kukalova-Peck & Lawrence ( 1 9 3 ) .

eyelet. but with a typically scarabaeoid thickened margin (Fig. 13). Glaresidae is the only group which retains the ancestral eyelet-like condition in Scarabaeoidea.

Central foldirig field

This is an area jast proximal to the radial cell and cross- vein r4, into which the apical folding field is drawn. In all primitive Coleoptera the central folding field [25] is triangular (Kukalovs-Peck & Lawrence, 1993). This is the condition in Gluresis and in no other scarabaeoid group. In other scarabaeoids the central folding field is irregular.

RA4 and RPI

I n the groundplan of the Haplogastra RA4 and RPl come close together to support the anterior apical margin. but do not fuse. I n scarabaeoids RA4 and RP1 are either not fused (primitive) (Figs 14-16) or fused (derived) [2h] (Fig. 17i). and RPI is primitively strong [27]. In Gluresis RP1 is apparently reduced (autapomorphy). Fusion between RA4 and RP1 happened many times in Scarabaeoidea (derived, convergent).

Trox

14

ScA

Omorgus

16

Figs 14-16. Venational systems of derived Scarabaeoidea: Trogidae. 14. Trox fuscicrrhrk. Length 12 mm. 15. Po/ynoncus mirobilk. Length 24mm. 16. Omorgus squalidus. Length 20mm.

a

Pol yphaga

b Hydrophiloidea: Staphylinoidea:

H ydrophilidae Agyrtidae

d Histeroidea:

Sphaeri tidae

e

S yntelidae

I

Histeridae

4

h 1

Scarabaeoidea : Trog i doe Scarabaeidae

Glaresidae

Fig. 17. Phylogenetic changes in wing venation of Polyphaga, hydrophiloid lineage. (a) Polyphaga groundplan. (b) Hydrophilidae: Dacfyfosfernurn sp. (c) Staphylinoidea: Agyrtidac: Necrophilus hydrophiloides. (d-f) Histeroidea: (d) Sphaerites glabrafus. (e) Synrrlia rnexicana. ( f ) Hololepta ausfralica. (g-i) Scarabaeoidea: (g) Glaresk wafzfae. (h) Trox fascicularir. (i) Phunerognatha enchsoni. (b- i): Radial cell proximally weakened. distally strengthened, apical hinge ‘pinched’, RA4 and RP1 approach, run in parallel of fused. (c-i): Cross-vein r3 and cross-vein rp-mp2 reduced, tip of RP and tip of medial bar fused, RP3 + 4 shifted posteriorly to meet medial spur. (c): Radial cell shaped like an inverted ogive arch, r4 shifted to its centre. (d-i): Radial cell distally strengthened. at an acute angle and progressively narrower, r4 shifted proximally. (g-i): RadiaI bend replaces radial hinge, r4 curved and ending on RP1 + 2, r3 progressively disappears.

Gloresidue, urchaeoptervx of the Scaruboroideo 269

CUP-

U

C

Histeroidea Scarabaeoidea

Hydrophiloidea Staphylinoidea Fig. 18. Phylogenetic changes in wing venation of the hydrophiloid lineage. (a) Hydrophiloidea: Dacrylosrernurn sp. (b) Staphylinoidea: Necrophilur bydrophiloides. (c-d) Histeroidea: ( c ) Sphaerifes glabratus (d) Synrelia rne.ricanu. (e-f) Scarabaeoidea: (e) GIaresis wulzlue (f) Syndesus cornufus. (a) Close to the groundplan. (b-f) CuA3 + 4 reduced. (b) AA branches reduced, AP1+ 2 retained. (c-f) AAI + 2 spike-like. ( e ) Posterior section of AAI + 2 retained (weak). ( f ) Same. lost.

270 C . H . Seholtz, D. J . Brawtze urrd 1. Kukufor,u-PrcX

RP3 + 4

In Coleoptcra (including Polyphaga and Haplogastra) the groundplan condition of the RP3 + 4 is curved, and its base is separated by a cross-vein (rp-mp2) from the short medial spur (Figs 17a-b). I n Staphylinoidea + Histcroidea + Scarabaeoidea (Figs 17c-i) this important cross-vein, which is part of thc polyphagan medial hook, is completely reduced, and R P 3 + 4 and the medial spur come close together. I n most scarabaeoids RP3 -k 4 and the medial spur 1281 both reach the posterior margin (primitive at thc Scarabaeoidea level), or RP3 -k 4 is more or less reduced and only the medial spur reaches the posterior margin (derived). In Chresis and the Trogidae RP3 + 4 is ccm- pletely reduced (derived), and the medial spur reaches the posterior margin. We conclude, consequently, that Cluresis, Trogidae and some other scarabaeoids have RP3 + 4 independently reduced.

Brurzch AAl + 2

I n the ancestral condition at the Haplogastra level, AAI + 7 fuses first with CuA3 + 4 and then with CuA2 before it reaches the posterior margin (Fig. 11). In the primitive condition in Scarabaeoidea + Histeroidca CuA3 + 4 is completely reduced and branch AAI + 2 is spike-like 1291. In G/urrsis AAI + 2 is spike-like as in other primitive scarabaeoids, but recovers its course ( in a weakened form) and reaches the posterior margin. Consequcntly. Cluresis has the most primitive A A I -t- 2 in Scarabaeoidea.

JA arid J P

I n the scarabaeoid groundplan JA and JP are present [30]. I n Gluresb JA and JP may be lost. In other Scara- baeoidea JA and JP may be present or absent. I n Claresis the absence of both JA and JP is derived.

Venational analysis of Gluresis shows that it has the most primitive (almost eyelet-like) radial cell of all Scarabaeoidea. The early divergence of the Coleoptera is marked by considerable changes in the radial loop and a primitive shape of the radial cell almost certainly provides a very strong character. Other important primitive features are the distinctly recognizable r4 cross-vein (instrumental in apical folding), and especially the retained end of the branch AA1+ 2 which has disappeared in all other scarabaeoids. These three characters distinguish the family Glaresidae clearly from the rest of Scarabaeoidea as having the most primitive strong character set in its hindwing venation. The above listed veinal apomorphies of Glaresidae occur randomly and repeatedly in many other scarabaeoid families.

In primitive coleopterans the wing articulation and wing base are characterized by the presence of easily distinguish- able venalia, which have. generally, retained their size, and in some cases their shape. Some fusion of theso venalia has occurred. most notably in the partial formation of the axillaries and basal plates. This trend has continued in the Scarabaeoidea. In the scarabaeoid ancestral condition, in most instances uniquely found in Glaresidae, the wing base and wing articulation are large and densely sclerotized. Articulations between components are broad and only small thin sections of connective membrane join them. but in some cases individual venalia still remain incompletely fused. The trends in the evolutionary development of the wing base and wing articulation are towards a much smaller size, relative to the wing foil, through reduction of the axillaries, median plate and basal plates, and complete fusion of venalia. Consequently, broad articulations bctween components have been eithcr reduced, but increased in firmness, or lost and replaced by broader anti stronger connective membranes. I n many cases pre-existing structures have become highly modilicd or uniquc structures hnve arisen t o rcplacc the lost primitive articulations.

Hiritlwitrg articiiliitiori

Firsr uxilkiry (Fig. 19). In t h c scarabxoicl ipuiidplari (Browne & Scholtz, 1994) thc head, ncck a n d tail arc broad [311. This is found in thc Glaresiclac arid i n miilly

primitive and derived groups. Dcrivcd types, found in othcr scarabaeoids. have the head and neck niassivc o r very narrow and the tail enlarged or reduced.

FScl, the ventrill projcction and FSc2 ;ire very short and narrow in the primitive state [37_]. This typc is found i i i

many primitive Scarabaeoidea, such as Glaresidac. somc Lucanidae, Diphyllostomaticlae and Tropidae. In the derived state the FSc treth and the ventral projection are much longer, enhancing the 1Ax-BScA articulation.

The distal embayment [331 is only weakly concave primitively. Glaresidae share this state with many other scarabaeoid taxa. In the derived state, the distal embayment is moderately deep to very deep.

The PRR articulation [34], in the ancestral state, is only weakly recurved, a condition unique to Glaresidac. The other groups display the derived state in which the PRR articulation is strongly recurved, folding up beneath the tergum. This articulation may be very long (Bolbo- ceratidae) or extremely short (Passalidae).

Second a i l l a p (Figs 20, 25). The ancestral condition, found only in Glaresidae, i s one in which: the proximal lobe is very small and strongly depressed below the ridge [35]; the distal lobe is very large and harp-shaped [36]; the anterior section of the proximal ridge is absent [37]; the dorsal ridge is weakly elevated and feeble and the anterior section is very short [%I: and the medial groove is very weak anteriorly [39]- The trends in the evolutionary development of 2Ax are towards: an elevated, large and strongly

PZ

02

e

Figs 19-24. Wing base and wing articulation structures of Gloresis walzlue. 19. First axillary (a) dorsal (length 250pm). (b) anterior (width Mpm) and (c) ventral (width 120pm) views. 20. Second axillary (a) dorsal. (b) ventral views (width 120pm). 21. Wing base and wing articulation: (a) scanning elcctron micrograph, (b) drawing. showing relative positions of axillaries. basal plates and median plate (width .UX)pm). 22. Third axillary, dorso-lateral view (length 250yrn). 23. First basal plate, dorsal view (length 300pm). 24. Second basal plate: (a) dorsal view (length 2MJpm). (b) schematic vcntral view illustrating RA ( 1 . BMA; 2, MA; 3. BMP; 4, BR).

7-72 C. H . Scholt;. D. J . Browtie uiid J , KiikuIot*[i- Peck

sclerotized proximal lobc; a smaller. deltoid or lingulate distal lobe: strongly elevated, strongly sclerotized. distinct and broad dorsal and ventral ridges; both ridges well extended beyond the anterior margins of the lobes; and a deep and extensive median groove. These modifications enhance the 2Ax-1Ax. 2Ax-FMI and 2Ax-IBP articulations.

I n the scarabaeoid groundplan FR is extremely largc and ovoid, broadly fused to both the anterior margin of the 2Ax distal lobe, and the ridge and the suture lines marking these junctions are absent [40]. This ancestral type is retained only in the Glaresidae. All other Scarabaeoidea exhibit the derived type, a relatively narrow or absent FR which is not fused to the lobe but rather to the ridge apex. A distinct suture line marks this junction. This is the only case in which the development of a suture line can be considered derived. The ancestral condition is one in which FR and AXM are completely fused, equally sclerotized and thus without a suture line. However, the gradual reduction in size and sclerotization of FR has led to the re-emergence of this suture line in the derived state.

Mediurr plufe (Fig. 21). The antero-median to posterior section of FMl is broad along the entire length with the proximal margin broadly articulated with 1Ax + 2Ax and the distal margin broadly articulated with 3Ax [41]. This primitive state is found in Glaresidae and some other scarabaeoid groups. The trends in the evolutionary development of the median plate are towards a narrower and smaller FM 1 with a less extensive articulation with 2Ax. The most derived state in the scarabaeoids occurs in the Athyreini (Bolboceratidae) in which FMI is strongly reduced, with only the terminus present as an extremely small remnant between IAx +?Ax and 3Ax. Therefore the reduction of the 2Ax-FM I articulation can be considered derived. However, this has occurred independently many times i n the Scarabaeoidea.

FM2 [42] is usually small, which is the primitive state found in Glaresidae and most othcr scarabaeoid families. The complete reduction of FM2 is the derived state found in some Scarabaeidae.

I n the primitive state FMI and FM2 are separated by a membrane [43]. This condition is found in Glaresidae and many other scarabaeoids. The complete fusion of FM 1 and FM2 is the derived state found in various groups. However, partial or complete fusion and reversals occur commonly in many unrelated taxa at diverse systematic levels.

Third uxillury (Fig. 22). The ancestral condition is one in which: the head is very broad and moderately convex [MI; the anterior margin is convex [45]; FCu is very large [46]: the posterior section of the ridge is absent [47]: AXCu is present as a very slender anteriad extension along the proximal margin of head 1481: the tail is very narrow and convex [4Y]; a window or medial weakening is absent [50]: and suture lines between AXA, AXJ and FJ are present [51]. Glaresidae share the primitive condition with other primitive scarabaeoids. The most derived states include: a weakly to deeply cleft head (higher Scarabaeidae): a proximally reduced FCu and small FA (some Scarabaeidae); a long, distinct and strongly elevated AXCu (Bolboceratidae); AXCu anteriorly extended distad reducing the size of FCu

(many soarahaeids); ;I broad tail with a window o r medial weakening (many scarabaeoids): and suture lines between the tail venalia reduced or absent (various groups).

H i d w i i i g buse

First hrisolplurr (Fig. 23). I n the scarabaeoid groundplan HP is only very weakly curved postero-dorsad 1521. This state is found in most of the primitive scarabaeoids, including Glaresidae. The derived state, found in the Scara- baeidae, is one in which HP curves postero-dorsad close to, or even over, BScA.

BScA. moderately large and oriented antero-distad, is the primitive type [Uj . I t is found in Glaresidae and many other scarabaeoids. A variety of different shapes is found in other groups.

A large and broad ScA which is separated from BScA by a deep concavity is primitive [54]. This condition is found in many scarabaeoid groups, including Glarcsidae. A variety of derived states is found in other groups.

The state in which BR is broadly open, long. partially depressed below BScA, with a very small proximal arch, and an indistinct br, is primitive [55]. This is found in the Glaresidae and various other scaribaeoid groups. Other groups exhibit the derived conditions: a moderately open to narrowly closed BR with the anterior margin dorsally elevated close to or above the ScA bulge, a large proximal and distal arch, and a distinct br.

Secotid basal plare (Figs 24. 26-27). In the ancestral condition, retained only by Glarcsidae, 2BP is: large, broad and moderately sclerotized [56]: BMA is distinct, strongly convex. partially anterior to BMP [j7]; a remnant of MA is present [%I; BMA and BMP are complctcly fused posteriorly, and incompletely so anteriorly ISU]: rind BMP is flattened and srrongly depressed below BMA [601. The evolution o f 2BP is towards: a smaller platc which is reduced o n all margins and more strongly sclerotized. with numerous secondary concavities and convexities; complete Fusion between BMA and BMP; BMA entirely proximal to BMP; MA absent; and BMP elevated. This is the derived condition exhibited by all other Scarabaeoidea.

In the scarabaeoid groundplan a slender, moderately sclerotized BMP-BCuA brace is present [61]. This is the condition in the Glaresidae and some derived Scarabaeoidea. Primitive scarabaeoid groups possess the BMP-CuA brace a:id often a reduced BMP-BCuA brace.

Abdominal sferriites (Fig. 28)

Five abdominal ventrites [62] (sternites 3-7) are readily visible in Lucanidae, Trogidae, Glaresidae and Passalidae (although the second is actuafly present in the form of small lateral sclerites in Passalidae). Six (sternites 3-8) are visible in the rest of the Scarabaeoidea except Diphyll- ostomatidae in which seven (sternites 2-8) are visible. It is not clear whether the presence of five is homologous in the Lucanidae, Trogidae and Glaresidae or whether

Cluresidue. urchaeopteryx of the Scurubueoideu 273

Figs 25-27. Scanning electron micrographs of wing base and wing articulation characters of Claresb walzlae. 25. Second axillary, illustrating (a) anterior section of distal lobe and ridge of 2Ax (AXM) and FR (length lM)pm), (b) relative positions of FR, and the dorso- distal ridge (d-dr) and dorso-distal lobe (d-dl) (width 25 pn). 26. Second basal plate illustrating (a) the incomplete junction between BMA and BMP (width 8Opm). (b) the transition from incomplete to complete fusion between BMA and BMP (width 5ym). 27. Second basal plate illustrating (a) details of the BMP-BCuA brace (width 150pm). (b) the junction between the BMP-BCuA brace and BCuA (width 20pm).

274 C. H . Scholtz. D. J . Browire aiid J . Kukulc>t*u-Prck

only five are visible as a possible result of connation of distal ventrites. Intuitively, the smaller number of visible ventrites would appear to be the derived condition but the groups with five are primitive in many other phylogenetically important characters so the possibility of reversals or non-homologous reductions cannot be ruled out.

Abdominal spiracles

The abdominal spiracles of adult Scarabaeoidea exhibit five main evolutionary trends (Ritcher, 1969a): (a) reduction from eight in the number of functional spiracles [63]: (b) reduction in size of posterior pairs (2-8) of spiracles or their openings [64]; (c) reduction in size of first abdominal spiracle [65]; (d) change i n structure of the filter apparatus from simple spinules to lips or solid walls [66]; (e) migration of one or more posterior pairs of spiracles from the pleural membrane into the tergites or sternites and, associated with the latter, a trend toward fusion of the tergite and sternite of the seventh abdominal segment [67]. Glaresidae have the primitive condition i n all of the above characters.

Male genitalia (Fig. 29)

Three types of aedeagi [68] are encountered in the Scarabaeoidea (d'Hotman & Scholtz, 1990). (a) In the trilobe-type the tegmen consists of a well-sclerotized basal piece and paired parameters which surround the well- developed, tubular median lobe. The genital segment [69] is usually present as a genital capsule. This type occurs in many of the primitive scarabaeoids. (b) A bilobe-type, in which the basal piece and parameres are well developed, a median lobe is absent and the genital segment is in the form of a U-IY-shaped spiculum gastrale, is found in

A R

28

u a

most Scarabaeidae as well as some Ceratocanthidae and Hybosoridae. (c) The geotrupine-type, as the name implies, occurs only in Geotrupinae. The aedeagus is asymmetrical and the basal piece and pararrieres are well sclerotized. The basal piece is large in relation to the parameres and dominates the entire aedeagus. The parameres are small and form a complete ring which articulates with the interior wall of the basal piece. The median lobe is membranous and the small unarmed internal sac lies within the tegmen. A genital capsule is present.

Glaresidae have a typical trilobed aedeagus and a genital capsule.

0vuriole.y

Six ovarioles [70] on each side is the most common number found in the Scarabaeoidea (Ritcher & Baker, 1974). However, the number varies from about 25 ovarioles in each ovary as in some Pleocomidae to the greatly reduced situation in the Scarabaeinae in which there is only one ovary with a single ovariole. Besides Plcocomidae, in which ovariole number also varies within a species, no group has more than 12 per side. Some Lucanidae, Rutelinae and Cetoniinae have 12 per side. One species of Rutelinae has 9 per side. The greatest variation is to be found in the Aphodiinae where 7, 6, 5 , 3 and 2 per side have been recorded. Six on each side have been recordcrl in some Lucanidac, Trogidae, Aphodiinae, Rutclinae and Cetoniinae and in Ochodaeidae, Geotrupidae. Glaphyridae. Ceratocanthidae and Melolonthinae. Glaresidae is the only family reported to have 4 ovarioles per side (Ritoher & Baker, 1974). Some Trogidae ( O n r o r p s ) and some Aphodiine have 3 per side and all Passnlidae and soiiie Aphodiinae have two per side.

Since ecological factors such as brood core obviously also influence the number of progeny producod. ovariole

b C

29

d

gs 28-29. Gluresis impressicollis, abdomcn and male genitalia. 2% Abdomen ventral view. illustrating tivc distinct stcrnitcs. 29. Malc genitalia: aedeagus in (a) dorsal. (b) ventral. (c) lateral view: (d) genital capsule. dorsal view.

Gluresidoe. urchutwptrryx of the Scuruhaeoidc.u 275

number is probably of little use in phylogenetic deduction. Nevertheless, based on commonality, the 6-6 condition appears to be the ancestral one, with increases or decreases representing derived conditions. I f this is so. there seems to be little reason to believe rhat the large number present in Pleocomidae is primitive. as suggested by, for example, Ritcher s( Baker (1974). The latter authors reported finding 4 ovarioles i n American Gluresis but two southern African species examined during the present study have 6. Males of the southern African species, however. have distinctly 4-lobed testes and the possibility exists that Ritcher s(

Baker, in fact, had males not females before them. In very small beetles such as these it is easy to confuse the sexes.

Kary otype

Because of the marked preponderance of nine pairs of autosomes and an Xyp sex-determining system [71] (‘modal system’ of Yadav SC Pillai, 1979) in the Scarabaeoidea the ancestral system has been postulated to have had a 9 + Xyp karyotype (Smith & Virkki, 1978; Yadav & Pillai, 1979) and that groups possessing different complements are derived forms. Five major changes have occurred in the evolution of scarabaeoid karyotypes: X-A fusion; A-A fusion; A fission; loss of the Y chromosome; and change from metacentry to acrocentry. However, interpretation of how this came about (Yadav s( Pillai, 1979), and of sex bivalents (Crowson, 19S1), is doubtful. Some authors (see Crowson, 19S1), have assumed that a small y, forming a ‘parachute-p’ figure in mitosis with a larger X, was a primitive feature which once lost could not be regained. Others have claimed that the addition of a pairing segment to the original y, leading to an Xy or XY bivalent, was a reversible process and that recent Xyp types are derived from Xy or XY ancestors. Loss of y results in XO, and the only sex bivalent which could develop from it is a neo-XY.

Chromosome numbers and sex determining systems differ greatly within the Scarabaeoidea with autosome numbers varying from 8 to 36, and with various sex- determining systems. The greatest variation in autosome number is in the Lucanidae (8-18), Passalidae (16-36) and Scarabaeinae (10-20) although many of the latter have the modal number. In Lucanidae the modal number has only been found in Aesalinae. It has not been recorded in Passalidae. Most Trogidae , Pleocomidae , Bolboceratidae, Glaphyridae, Ceratocanthidae, Hybosoridae and Glaresidae have the modal number, as do most Aphodiinae, Melo- lonthinae, Rutelinae (except Rutelini with 2n = 22), Dynastinae and Cetoniinae.

Based on the non-chiasmate Xyp [72] sex chromosome, Smith s( Virkki (1978) concluded that Gluresis is the most primitive living scarabaeoid genus.

Fossil record

The oldest probable scarabaeoid, Aphodiites, is known

from the Lower Lias (Lower Jurassic) of Switzerland. I t is small (5mm long) and claimed to be aphodiine-like. I t has striated elytra and a large prothorax. The diagnostic characters attributed to Aphodiifes could equally apply to a Glaresis-like beetle. Nikolajev (1992) recently reviewed the Mesozoic scarabaeoid fossils.

Discussion

Out of all the characters studied, only two autapomorphic states, those of reduced RP1 and RP3 + 4 vein branches, could be unequivocally assigned to the Glaresidae. Although reductions are usually considered to carry little phylogenetic information, the above reductions are found only in Glaresidae, so we are satisfied that the family is monophyletic. The rest of the Scarabaeoidea (excluding Glaresidae) share many apomorphic characters (e.g. twelve wing base and wing articulation characters (Browne, 1993)) so they unquestionably represent a monophyletic lineage. The derived states of seven characters may be shared among Glaresidae and various other primitive scarabaeoid groups. In all others the basic condition is found in Glaresidae. In many instances it is the only group in the superfamily with the absolutely basic condition (plesio- morphy) or it shares (symplesiomorphy) the most primitive condition of the particular character with one or more other groups.

The seven derived character states that Glaresidae ostensibly share with other scarabaeoid groups apparently contradict the hypothesis that they are the sister-group of all other Scarabaeoidea. However, most of these character states are not cladistically unequivocal since some are clearly reduced states of the characters (i.e. weak characters) or are not clearly homologous in the groups purportedly related.

Consequently, the only two characters that to our minds are unequivocally more primitive in groups other than Glaresidae are the exposed protrochantin and the open procoxal cavities. However, the two families that have one (Diphyllostomatidae) or both (Pleocomidae) primitive states have numerous characters in more derived states which they share with other scarabaeoid groups than do Glaresidae. Although the states of the other five characters which Glaresidae ostensibly share with some other taxa appear to be more derived than is the putative ancestral state, this cannot be stated with complete confidence.

Consequently, we are convinced that Glaresidae are the most primitive living scarabaeoids and represent the sister group of the rest of Scarabaeoidea.

Diagnosis

A diagnosis of the Glaresidae is given below. Because we are of the opinion that glaresids are the most primitive living scarabaeoids, and are consequently most similar to the ancestral scarabaeoid, the diagnosis can also serve as a character groundplan for the Scarabaeoidea. However,

276 C. H. Scholtz, D. J. Brownr urrtl J. Kiiktilo~xi-Prck

characters which are more primitive in groups other than Glaresidae are given in square brackcts.

Adults are characterized by: 10 [ 1 I]-Jointed antennae with a 3-jointed club; eye with [without] a canthus, and with eucone ommatidia: epipharynx [intermandibular projection] with single tormae and lateral combs not i n rows: mandibles toothed, with a prostheca and distinct molar area [without prostheca and molar area]; maxilla with lobed galea and lacinia terminating in two teeth, palpi 4jointed; labium consists of fused mentum and prementum, and a triangular, partly bilobed ligula; tentorium [invaginated] with single-foramen and small anterior and median bridges: protrochantin concealed [exposed]; procoxal cavities closed [open]; mesocoxal cavities open: generalized mesothoracic spiracles and intersegmentalia; wings with radial cell eyelet-like, distally strengthened; central folding field triangular: RPl reduced [ RP1 present]; RP3 -t 4completelyreduced [RP3 + 4 reaches the posterior wing margin]: medial spur reaches the posterior margin; A A l + 2 spike-like but recovers its course and reaches the posterior margin: JA and JP partially reduced [not reduced]; 1Ax broad, ventral projection and FScl very short and narrow, distal embayment weakly concave, and PRR articulation very weak: 2Ax proximal lobe very small, strongly depressed below the ridge. distal lobe very large and harp-shaped, anterior section of the dorso-proximal ridge absent, clorso-distal ridge weakly elevated, feebly distinct and the anterior section very short, medial groove very weak anteriorly, FR strikingly broadly ovoid and large, and very broadly articulated with the distal ridge and lobe; median plate broadly articulated with 1-3Ax, FMI and FM2 separated by membrane and FM2 small; 3Ax head dorsally very broad amd moderately convex, anterior margin convex, FCU very large, posterior section of the neck ridge absent, AXCu present as a very slender anteriad extension along the proximal margin of head, tail very narrow and convex, window or medial weakening absent, and suture line between AXA, A N and FJ present: 1BP with HP very weakly curved posterodorsad, BScA moderately large and oriented antero-distad, ScA large and broad. separated from BScA by a deep concavity, B R broadly open, long, partially depressed below BScA, with a very small proximal arch, an indistinct br and distal arch absent; 2BP large, broad, moderately sclerotized with BMA distinct, strongly convex, partially anterior to BMP, BMA and BMP completely fused posteriorly and incompletely so anteriorly. BMP flattened and strongly depressed below BMA, BMP-BCuA brace slender, moderately sclerotized and MA weak but present; tarsal empodium absent; 5 visible abdominal ventrites; abdominal spiracles situated in pleural membrane, all functional; male genitalia a simple symmetrical trilobe: genital capsule distinct: 4 or 6 ovarioles present per ovary: karyotype 9 + Xyp.

Acknowledgments

We are grateful to Marita Johnson (Pretoria) for many of the drawing used in this paper and to Stan Caveney

(London, Canada) for the SEM used in Fig. 4. This work was funded by the Foundation for Research Development of South Africa (C.H.S. and D.J.B.) and the Natural Sciences and Engineering Research Council of Cdnada (J.K.-P.).

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Scholtz. C.H., d’Hotman. D. & Ncl, A. ( lYX7) Glarcsidac, a ncw family of Scarabacoidca (Colcoptcra) to accommodak thc genus Glaresis Erichson. Systematic Entomology. 12. 345-354.

Scholtz. C.H., d’Hotman, D., Evans, A.V. & Ncl. A. (1988) Phylogeny and systematics of thc Ochodaeidac (Coleoptera: Scarabaeoidca). Journal of the Entomological Society of Soulkern Africa, 51, 207-240.

Smith, S.G. & Virkki, N. (1978) Animal Cytogenetics, Vol. 3. Insccta 5 . Gebriider Borntraegcr. Berlin.

Yadav. J.S. & Pillai. R.K. (1979) Evolution of karyotypcs and phylogcnctic relationships in Scarabacidac (Coleoptcra). Zoo- logisclter Anzeiger. 202, 105- 118.

Acccptcd 18 April 1YY4

glaresidae, archaeopteryx of the scarabaeoidea (coleoptera)

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