Research Article |
Corresponding author: James К. Liebherr ( jkl5@cornell.edu ) Academic editor: Thorsten Assmann
© 2020 James К. Liebherr.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Liebherr JК (2020) Sporades jaechi sp. nov. with comments on classification of the New Caledonian genus Sporades Fauvel (Coleoptera, Carabidae, Trechini, Trechodina). ZooKeys 908: 123-136. https://doi.org/10.3897/zookeys.908.48707
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Sporades jaechi sp. nov. from Poum, New Caledonia is newly described and shown to be a member of the monophyletic Sporades subgenus Perileptosporades Deuve, 2010. Sporades millei Giachino and S. schuhi Donabauer are newly recognized as members of the subgenus Perileptosporades, and a key to its species is provided. Although Perileptosporades can be defined monophyletically relative to the rest of the genus, genitalic variation among species assigned to the nominate subgenus Sporades Fauvel, 1882 leave monophyly of that taxon ambiguously supported. Several morphological characters of long- standing use have been proposed to define the mutual monophyly of Sporades s. l. and its putative adelphotaxon, Trechodes Blackburn, 1901. Increasing knowledge concerning the diversity of male genitalic characters among Sporades spp. lends support to a recently proposed molecular phylogenetic hypothesis positing that Sporades evolved from within Trechodes. The consequences of the alternate phylogenetic hypotheses on their attendant nomenclature are discussed. An additional locality record for S. sexpunctatus Fauvel expands the known distribution of this species to include most of Grande Terre, New Caledonia.
aedeagus, genitalia, phylogenetics, taxonomy
Fauvel established Sporades for his species S. sexpunctatus (
Sporades remained monotypic until
This contribution adds one more new species to the New Caledonian Sporades fauna. The new species described below is placed in subgenus Perileptosporades, with a preliminary assessment of relationships of the five species assignable to that subgenus provided. Cladistic relationships of the two Sporades subgenera, and Sporades s. l. relative to Trechodes are discussed in light of information derived from morphological characters and molecular sequence data (
This contribution is based on two specimens received on loan from the Naturhistorisches Museum Wien, Austria (
Dissection techniques and macro-photographic procedures follow those of
Body length was measured as the distance from the mandibular apices to the elytral apex, measured in linear segments along the dorsal body midline. Body measurement abbreviations follow
EL elytral length as above;
EW maximal elytral width;
HW head width;
PA apical width of pronotum measured between anteriormost margins of front angles; PB, basal width of pronotum;
PW maximal pronotal width;
PL median length of pronotum.
Terminology for trechine anatomy follows
Holotype male, point mounted, dissected, apical three abdominal ventrites glued onto point (
Assignable to the subtribe Trechodina based on the tridentate mandibles bearing an obtuse tooth between the mola and retinaculum (
Male holotype body length 3.0 mm from mandibular apex to elytral apex. Head, pronotum, elytra and femora ferruginous, maxillary and labial palpi flavous, all antennomeres rufoflavous, and tibiae and tarsomeres rufobrunneous; head and pronotum with well-developed microsculpture, isodiametric to transversely stretched isodiametric medially on frons, vertex and pronotal disc, more transverse on ocular lobes and lateral margins of pronotum; elytra glossy, transverse sculpticells partially covering convexities surrounding depressions associated with setal insertions of elytral pelage.
Head broad, HW/PW = 0.92, eyes convex but outer curvature consistent with that of ocular lobe behind eye; frontal grooves deepest between hind margins of eyes and anterad near fronto-clypeal suture; two supraorbital setae; four clypeal setae; labrum deeply and arcuately excavate medially, with a distinct obtuse tooth along midline of excavation; mandibles elongate, distance from dorsal condyle of left mandible to mandibular apex ~ 2 × distance from condyle to anterolateral apex of labrum; antennae filiform, antennomere IX length 4× maximal breadth; submentum with six setae arcuately arranged across width of convexity fused to gula; mentum with oblique longitudinal depressions terminated posterad mentum setae, and with acute median tooth bearing a longitudinal median groove; ligula convex medially, paraglossae porrect, elongate (
Pronotum moderately broad, PW/PL = 1.31; base constricted, PA/PB = 1.11, PW/PB = 1.32, hind angles narrowly rounded, protuberant, basal pronotal setae set on concave margin anterad angle; median base straight, forming a transverse collar extended posterad finely margined lateral lobes bearing hind angles, the base finely margined across width, isolated from disc by broad, well-developed basal transverse impression that is deepest and narrowest anterad carinate hind pronotal margin mesad hind angles; median longitudinal impression fine and shallow on disc; anterior transverse impression broad and deep, extended to front margin mesad front angles and defining a broadly convex anterior collar that is distinguished from the disc by its glossy surface due to very shallowly margined sculpticells; front angles nearly imperceptibly protruded, the pronotal margin rounded there to the narrow lateral marginal depression; anterior pronotal setae placed far forward along margin, 0.19 × distance from front posterad to hind angle.
Elytra elongate, quadrate, lateral margins nearly parallel at midlength, the elytra broadest near apical 1/4, EW/EL = 1.62; disc flat to slightly depressed laterad elevated sutural interval; parascutellar seta present mesad base of stria 1, equidistant from stria and basal groove; basal groove slightly recurved from sutural stria to broadly rounded humeri; lateral marginal depression narrow but with sculpticells visible at depth, depression broadest anterad very short recurrent stria, elytral margin slightly concave there; striae 2 and 3 traceable on disc, though depressions are obscured by punctures associated with elytral setal pelage, outer striae not visible; two dorsal elytral setae present in third stria, plus a third posterior seta present mesad apex of very shallow, difficult to trace recurrent stria; subapical and apical setae present, former at base of recurrent stria, latter inside marginal bead near rounded elytral apex; lateral elytral setae arranged as four anterior setae posterad humerus, two setae isolated ~ 0.650.70 × elytral length, and two setae laterad recurrent stria at ~ 0.90 × elytral length; elytral surface covered with setal pelage, the setae as long as the distances between them, their arrangement tending to longitudinal series of setae, especially traceable in the sutural stria; metathoracic flight wings fully developed with complete venation.
Ventral surface bearing both macrosetae and a shorter setal pelage; prosternum with setal pelage medially and a transverse series of ten macrosetae along anterior margin; metathoracic ventrites and metacoxae with setal pelage; abdominal ventrites with setal pelage of similar development to that of elytra; apical ventrite of male with one seta on each side along apical margin which is slightly concave along midline.
(N = 1). Aedeagus lightly sclerotized, small relative to large, λ-shaped antecostal apodeme of abdominal segment IX (Fig.
Male aedeagus of Sporades jaechi holotype: 2 aedeagus in situ with laterotergite IX and tergites of abdominal segments VIII and IX 3 male aedeagus, dextral view 4 male aedeagus, sinistral view. Abbreviations: ae, aedeagus; lt IX, laterotergite IX; mt VIII, mediotergite VIII; mt IX, mediotergite IX; lp, left paramere; rp; right paramere. Scale bars 0.10 mm.
This species is named to honor the collector of the unique holotype, Dr. Manfred Jäch; a noted world authority on water beetle systematics and biodiversity.
Known only from northernmost Grande Terre (Fig.
This key is based on information presented in
1 | Pronotum glabrous or very sparsely setose, lateral marginal depression narrow | 2 |
– | Pronotum densely setose, covered with a pelage of short setae, lateral marginal depression broad | Sporades theryi Deuve |
2 | Pronotum either with a shallow anterior transverse impression, or the impression obsolete, the medioanterior portion of pronotal disc not upraised in a distinct collar; male aedeagal apex narrow dorsoventrally, the dorsal and ventral margins subparallel basad the narrowly rounded tip ( |
3 |
– | Pronotal anterior transverse impression deep, broad, arcuate, defining a glossy, raised anterior collar (Fig. |
Sporades jaechi sp. nov. |
3 | Elytral recurrent vein very reduced to obsolete, apical elytral margin not interrupted; aedeagal median lobe distinctly downcurved, apex extended beyond straight shaft of lobe ~ 2× dorsoventral breadth ( |
4 |
– | Elytra with evident, short recurrent vein that interrupts apical elytral margin; aedeagal median lobe slightly downcurved, apex extended beyond straight shaft of lobe ~ 3× dorsoventral breadth ( |
Sporades schuhi Donabauer |
4 | Pronotum glabrous except for lateral and basal macrosetae ( |
Sporades modestior Deuve |
– | Pronotum with sparse pelage of very short setae accompanying lateral and basal macrosetae ( |
Sporades millei Giachino |
This species is easily diagnosed among all Sporades by the male aedeagus, wherein the median lobe is expanded and twisted apically (
Sporades jaechi represents the fifth species of sg. Perileptosporades. Of the five species, S. theryi deviates most strongly based on larger body size, a different aedeagal median lobe configuration, a shorter, broader apex, and an extensive setal pelage on head, pronotum, and elytra (
presence of the elytral basal groove;
the narrow, spindle-shaped apical maxillary palpomere contrasted to the broader, medially expanded penultimate segment;
a flat pronotum with mediobasal projection;
a deep sutural stria that is smoothly joined to the basal groove laterad the scutellum; and
a broadly widened aedeagal median lobe apex.
He noted that the two genera could be distinguished by the relatively short parameres of Trechodes spp. versus the robust, elongate parameres of Sporades sexpunctatus, the only species known at the time.
Also, the pronotum of Trechodes spp. is markedly protuberant medially along the pronotal base, with the pronotal hind angles situated well forward of the median base. Trechodes attains a very broad geographic distribution, ranging from Australia, the Philippines, Southeast Asia, Madagascar, and Africa (
The aedeagus of Trechodes spp. is characterized by an elongated median lobe with a narrowly attenuated apex, the tip of that apex bearing a hook, knob, or another type of curved appliance. For many of the species, the presence of spines on the internal sac is documented (e.g.,
Monophyly of Sporades relative to Trechodes is established based on the derived condition of only the basal male protarsomere dilated and bearing ventral squamose setae, and the presence of a fine setal pelage on the elytra (
Recent molecular systematic results (
This contribution maintains the taxonomic independence of Trechodes and Sporades in the face of ambiguously conflicting morphological and molecular phylogenetic evidence. Both genera are presently diagnosable via observable morphological characters, although the polarity of their attendant character states may require reassessment in light of additional phylogenetic data from all sources. Should these two genera be synonymized in order to recognize monophyletic taxa, the geographically widespread Trechodes Blackburn, 1901 must fall into synonymy under the New Caledonian precinctive Sporades Fauvel, 1882. Such a happenstance illustrates that taxonomic nomenclature operates by stable rules (
I thank Manfred Jäch, Museum of Natural History, Vienna, for the loan of New Caledonian specimens, and Arnaud Faille for his thorough and insightful review of the manuscript. To a person, all describers of Sporades have strived to provide information not only sufficient to diagnose the species, but also to advance scientific understanding of this taxon. These efforts are acknowledged, as they establish the basis for description of this new species without risk to the type specimens of these rarely collected species.