Corresponding author: Helena Shaverdo (
Academic editor: Mariano Michat
Detailed information about the known species groups of
Shaverdo H, Balke M (2022) A species-group key and notes on phylogeny and character evolution in New Guinean
The genus was proposed by
However, New Guinea is the core of species diversity of the genus and, therefore, was the focus of our taxonomic project started in 2012. Since the publication of
This paper aims to unite and discuss all known information on systematics of the New Guinean
Our study is based on published articles on the taxonomy of New Guinean
The results are presented as a species-group table and a key to species groups. The table includes all known species groups of New Guinean
We recognise 26 species groups of New Guinean
Most of the species in New Guinea are lotic, that is, associated with running water habitats. All of these species form one monophyletic group and are, thus, endemic to the island. The only exception is the stagnophilous species
Checklist of the species groups of New Guinea
N | Species group | Number of spp./subspp. | Species distribution | Reference with species-group diagnosis, key, species descriptions |
---|---|---|---|---|
IN (Indonesia): Province: Regency | ||||
PNG (Papua New Guinea): Region: Province | ||||
1 |
|
4 | ||
2 |
|
1 | ||
3 |
|
2 | ||
4 |
|
5 / 1 | ||
5 |
|
1 | ||
6 |
|
5 | ||
7 |
|
24 | ||
8 |
|
15 | ||
9 |
|
62 / 3 | ||
10 | 1 |
|
||
11 |
|
1 |
|
|
12 |
|
4 | ||
13 |
|
1 |
|
|
14 |
|
3 | ||
15 |
|
1 |
|
|
16 |
|
1 |
|
|
17 |
|
1 |
|
|
18 |
|
1 |
|
|
19 |
|
4 / 1 |
|
|
20 |
|
1 |
|
|
21 |
|
1 | ||
22 |
|
2 |
|
|
23 |
|
2 | ||
24 |
|
3 | ||
25 |
|
4 |
|
|
26 |
|
2 |
|
The key is proposed for identification of the species groups and species in the case of monotypic groups. The keys to species of individual groups can be found in the publications listed in Table
The key is mostly based on male characters, but organised in a way to get one as far as possible with female identification. In many cases, females cannot be assigned to species due to the similarity of their external and internal structures (for female genitalia see figs 17a, b in
1 | Elytron covered with short longitudinal strioles (Fig. |
|
– | Elytron without strioles |
|
2 | Pronotum with lateral bead, rarely narrow but distinct |
|
– | Pronotum without lateral bead, sometimes (especially in females) with bead traces or even narrow bead, in this case several specimens of population should be checked |
|
3 | Male protarsomere 5 strongly modified: concave ventrally, sometimes with anteroproximal setae enlarged. Male protarsomere 4 with anterolateral hook-like seta small, not developed (Fig. |
|
– | Male protarsomere 5 not modified. Male protarsomere 4 with anterolateral hook-like seta small to large (Fig. |
|
4 | Median lobe of aedeagus with discontinuous outline in ventral and often in lateral views (Fig. |
|
– | Median lobe of aedeagus with continuous or slightly discontinuous apically outline in ventral view |
|
5 | Paramere with most of setae very short, inconspicuous, some distal setae stronger. Median lobe without setae, with continuous or slightly discontinuous apically outline in ventral view (Fig. |
|
– | Paramere with strong and long distal setae, rarely with all setae very short, inconspicuous. Median lobe with or without setae, with continuous outline |
|
6 | Median lobe with fork-like apex of ventral sclerite (Fig. |
|
– | Median lobe with apex of ventral sclerite more or less deeply separated in two (rarely three) lobes (Fig. |
|
7 | Male antennomere 2 distinctly larger than other antennomeres (Fig. |
|
– | Male antennomeres simple or differently modified |
|
8 | Paramere with very short, inconspicuous setae. Median lobe with minuscule tip of apex curved upwards in lateral view (Fig. |
|
– | Paramere with long, distinct setae. Median lobe with broadly pointed apex in lateral view (Fig. |
|
9 | Median lobe in ventral view with distinctly concave apex forming two apical lobes |
|
– | Median lobe in ventral view pointed, truncate, or rounded, without two apical lobes |
|
10 | Median lobe long and slender, with fine apical setae; its apical lobes narrow and concave in lateral view (Fig. |
|
– | Median lobe shorter and more robust, without setae; its apical lobes broader, usually rounded in lateral view (Fig. |
|
11 | Median lobe very broad, robust, almost parallel-sided, with weak median constriction in ventral view; lateral sides strongly thickened; apexes of ventral sclerites very unequal: right one much longer than left one (Fig. |
|
– | Median lobe slender and of different shape; lateral sides not or only slightly thickened; apexes of ventral sclerites equal or slightly unequal in length |
|
12 | Median lobe with setae |
|
– | Median lobe without setae |
|
13 | Beetle larger, TL–H 5.3–5.8 mm |
|
– | Beetle smaller, TL–H 3.4–4.75 mm |
|
14 | Paramere with distinct dorsal notch and subdistal part well developed (Fig. |
|
– | Paramere without dorsal notch, slightly concave, subdistal part not evidently separated (Fig. |
|
15 | Subdistal part of paramere large, long, with numerous strong setae |
|
– | Subdistal part of paramere small, with a tuft of setae |
|
16 | Pronotum with distinct lateral bead. Median lobe longer and slender; lateral sides not thickened; in ventral view, narrow, slightly tapering to narrowly rounded apex; in lateral view, apex thin and elongate (Fig. |
|
– | Pronotum with narrow lateral bead. Median lobe shorter and more robust, lateral sides slightly thickened; in ventral view, broadened medially or subdistally, apex broadly pointed or slightly concave; in lateral view, apex thicker, not elongate (Fig. |
|
17 | Median lobe robust, apex with strong, short prolongation, curved downwards in lateral view (Fig. |
|
– | Median lobe slender, evenly curved, apex without apical prolongation, very slightly curved downwards in lateral view (Fig. |
|
18 | Paramere with dorsal setae divided into distinct, evidently stronger subdistal setae and inconspicuous proximal ones due to much weaker median setation (Fig. |
|
– | Paramere with dorsal setae uniform, inconspicuous or distinct, or with proximal setae distinct and long, sometimes stronger than subdistal (Fig. |
|
19 | Median lobe almost parallel-sided, often narrowed distally before or to apex or broadened subdistally; its apex usually with thickened sides, slightly or distinctly enlarged (“swollen”, often in shape of a baby pacifier), rounded, truncate, or slightly concave in ventral view (Fig. |
|
– | Median lobe different. Apex without such modifications |
|
20 | Median lobe thinner in apical half; in ventral view, evenly attenuated to pointed apex and, in lateral view, evenly broad, with rounded apex; its lateral margins slightly thickened (Fig. |
|
– | Median lobe more robust; evenly attenuated to bluntly pointed apex in ventral and lateral views; lateral margins not thickened, right one can be slightly concave distally in lateral view (Fig. |
|
21 | Median lobe in lateral view slender, almost straight, only apex distinctly curved downwards; in ventral view, with apex very broadly rounded (Fig. |
|
– | Median lobe in lateral view broader, more strongly curved, more or less evenly attenuated to thinner apex; in ventral view, apex bluntly pointed (Fig. |
|
22 | Median lobe with discontinuous outline in ventral and often in lateral views (Fig. |
|
– | Median lobe with continuous outline |
|
23 | Male antennomeres extremely modified: antennomeres 4–6 excessively large, 3 and 7 strongly enlarged (Fig. |
|
– | Male antennomeres simple or slightly enlarged |
|
24 | Apex of median lobe with two lateral and one dorsal prolongations (Fig. |
|
– | Apex of median lobe without such modifications |
|
25 | Paramere with numerous small spines, no long setae. Apex of median lobe thick, short and slightly curved downwards, its minuscule tip curved upwards in lateral view (Fig. |
|
– | Paramere with long setae. Apex of median lobe pointed or rounded, without such modifications |
|
26 | Median lobe with distinct subapical setae |
|
– | Median lobe without setae, in some species with minuscule spines |
|
27 | Beetle larger, TL–H > 4.5 mm. Apex of median lobe pointed in lateral view and rounded in ventral view (Fig. |
|
– | Beetle smaller, TL–H < 3.6 mm. Apex of median lobe roundly truncate in lateral view and concave in ventral view (Fig. |
|
28 | Apex of median lobe with thickened sides, often distinctly enlarged (“swollen”), in lateral and ventral views often of shape of a baby pacifier, rounded, truncate, or slightly concave in ventral view (Fig. |
|
– | Apex of median lobe of different shape, relatively thin, elongate in lateral view and broadly truncate in ventral view |
|
29 | Beetle larger, TL–H 3.7–4.35 mm. Male antennomeres enlarged. Median lobe longer. Paramere with numerous small and few large proximal setae; large setae with basal prolongations (Fig. |
|
– | Beetle smaller, TL–H 3.2–3.6 mm. Male antennomeres simple. Median lobe shorter. Paramere only with small proximal setae (Fig. |
|
Median lobe in ventral view of
Median lobe in ventral and lateral views of
Median lobe in ventral and lateral views of
Median lobe in ventral and lateral views of
Median lobe in ventral and lateral views of
Habitus, median lobe in lateral view and paramere of
The infrageneric structure of New Guinean
Earlier phylogenetic analyses based on molecular data substantiated the lotic New Guinean
A second colonization event was by a lentic species, evident from the presence of only one extant species, i.e.,
The 151 lotic New Guinean
Clade II itself also consists of two large subclades (1 and 2 in Fig.
Phylogenetic relationships and species-group structure of
Phylogenetic position of
More than 20 different morphological characters were used to describe species and organise species into a species-group structure. Some characters are very diverse and have more than 10 different states, e.g., antennal shape (9 states), shape of the median lobe (14 states), setation of the dorsal side of the parameres (12 states). Here, we briefly discuss characters, which we think are the most taxonomically and phylogenetically important and worthy of further study, not only as separate characters but also in combination.
The shape of the median lobe and paramere and their setation are very diverse and serve as the basic characters for species-group structure in New Guinean
Almost every species group has its own characteristic shape of the median lobe and paramere and their setation or combination of these characters. As already mentioned above, the most problematic was the placement of species of the
Presence and part or complete reduction of the lateral pronotal bead are states of this actively used in the key character. It is helpful for species identification, but could not be used reliably for phylogenetic purposes. Absence of the lateral pronotal bead is obviously homoplastic. It has developed independently probably up to eight times within New Guinean
New Guinean
Hook-like anterolateral seta of male protarsomere 4 is the main diagnostic character of the genus
Allocation of four more significant morphological characters amongst
New Guinean
We are grateful to Prof. David Bilton (Plymouth) for a linguistic review of the manuscript, Dr Lars Hendrich (Munich) for data on Australian