Research Article |
Corresponding author: Thomas Kaltenbach ( thomas.kaltenbach@bluewin.ch ) Academic editor: Dominique Zimmermann
© 2021 Thomas Kaltenbach, Jhoana M. Garces, Jean-Luc Gattolliat.
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:
Kaltenbach T, Garces JM, Gattolliat J-L (2021) Philibaetis gen. nov., a new genus from the Philippines (Ephemeroptera, Baetidae). Deutsche Entomologische Zeitschrift 68(1): 1-20. https://doi.org/10.3897/dez.68.59462
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Investigations of type material and new material from the Philippines (Luzon) revealed that Baetis luzonensis Müller-Liebenau, 1982 and B. realonae Müller-Liebenau, 1982 do not belong to Baetis Leach, 1815. A new genus, Philibaetis gen. nov., is described to accommodate both species and both are re-described based on larvae. The new genus is characterised by having a rectangular labrum with a submarginal row of long, simple setae on the dorsal surface and ventrally on lateral margins long, simple, spine-like setae, on anterolateral margins long, feathered setae and medially long, bifid setae and a partial, submarginal row of lanceolate setae. Both mandibles have blade-like incisors and dorsally, a mediolateral patch of long, spine-like setae; additionally, the left mandible has a tuft of long, partly branched setae at the base of the subtriangular process. Philibaetis gen. nov. is further characterised by a hypopharynx with a medial tuft of stout setae and anterolaterally, two smaller tufts of stout setae, a galea-lacinia with the distal denti-seta tooth-like and directed against canines, a fore femur apically with stout setae, both on anterior and posterior side and without a femoral patch and a claw with one row of denticles and two or three subapical setae. The protogonostyli under the cuticle of male last instar larvae are folded in the Labiobaetis type, excluding their affiliation to the genus Baetis. COI sequences were obtained from both species. The genetic distance (Kimura 2-parameter) between them is 17.5% on average. Very limited genetic distances of 0% to 3% (0.75% on average) were found between specimens of P. luzonensis comb. nov.
COI, Labiobaetini, mayflies, morphology, subapical setae
The family Baetidae has the highest species diversity amongst mayflies, comprising ca. 1,100 species in 114 genera (
The Philippines are a complex archipelago with more than 7500 islands, spanning the Asian-Australian faunal zone interface directly at the Wallace Line. Its extraordinary biodiversity was presumably supported by the complex biogeographic history and isolation of the archipelago, including landmass movements, collisions between landmasses of different origin in Miocene and temporary Pleistocene land bridges which were possible colonisation pathways of species, but also by environmental gradients along steep volcanic slopes (
Here we describe a new genus from the Philippines, based on the type material of Baetis luzonensis Müller-Liebenau, 1982 and B. realonae Müller-Liebenau, 1982, as well as larvae collected in 1997 and 2019 in four different locations in the Philippines (Luzon). Further collections of Ephemeroptera and especially of Baetidae in the Philippines and other parts of Southeast Asia will unveil more unknown genera and many more species in the future.
The new material was collected in 1997 and 2019 in four different locations in the Philippines (Luzon). Many more locations were sampled in this period without further findings of one of the two species (
The DNA of part of the specimens was extracted using non-destructive methods allowing subsequent morphological analysis (see
The GenBank accession numbers are given in Table
Species | Locality | Specimens catalogue # | GenBank # (COI) | GenSeq Nomenclature |
---|---|---|---|---|
P. luzonensis comb. nov. | Philippines: Luzon | GBIFCH 00763644 | MT873541 | genseq-4 |
GBIFCH 00763652 | MT873543 | genseq-3 | ||
GBIFCH 00763656 | MT873545 | genseq-3 | ||
GBIFCH 00763653 | MT873544 | genseq-4 | ||
P. realonae comb. nov. | Philippines: Luzon | GBIFCH 00763650 | MT873542 | genseq-4 |
Drawings were made using an Olympus BX43 microscope. Photographs of larvae were taken using a Canon EOS 6D camera and the Visionary Digital Passport imaging system (http://www.duninc.com) and processed with Adobe Photoshop Lightroom (http://www.adobe.com) and Helicon Focus version 5.3 (http://www.heliconsoft.com). SEM pictures were taken using a FEI Quanta FEC 250 electron microscope (Thermo Fisher). Photographs were subsequently enhanced with Adobe Photoshop Elements 13.
The distribution maps were generated with SimpleMappr (https://simplemappr.net,
The terminology follows
Abbreviations:
AdMU Ateneo de Manila University, Quezon City (Philippines)
MZL Museum of Zoology Lausanne (Switzerland)
Philibaetis luzonensis (Müller-Liebenau, 1982) comb. nov., by present designation.
Philibaetis realonae (Müller-Liebenau, 1982) comb. nov.
Larva. This new genus is distinguished by a combination of the following characters: A) body elongate and slender, head clearly hypognathous (Fig.
Philibaetis luzonensis comb. nov., larva morphology: a. Labrum, dorsal view; b. Labrum, ventral view; c. Seta on anterolateral margin; d. Medial setae; e. Labrum, ventral view, submarginal row of setae; f. Setae of submarginal row; g. Right mandible; h. Right prostheca; i. Left mandible; j. Left prostheca; k. Tuft of setae; l. Right incisor, kinetodontium and prostheca; m. Left incisor, kinetodontium and prostheca.
Unknown.
Philibaetis is an arbitrary combination of letters with allusion to the Philippines, where the genus occurs and to the genus Baetis. The latter is with reference to the superficial similarities between both genera and the fact that the species of Philibaetis gen. nov. were up to now assigned to Baetis. Gender is masculine.
Larva. (Figs
Body. Elongate and slender, head hypognathous (Fig.
Head
. Antenna (Figs
Labrum (Figs
Right mandible (Fig.
Left mandible (Fig.
Hypopharynx (Fig.
Maxilla (Fig.
Labium (Fig.
Thorax. Hind protoptera (Fig.
Foreleg (Fig.
Abdomen. Gills (Figs
Paraproct (Figs
Caudal filaments (Fig.
Unknown.
(Fig.
Larva. The following characters distinguish P. luzonensis comb. nov. from P. realonae comb. nov.: A) abdominal tergite IV without spines at posterior margin; B) tarsus dorsal margin with row of short, stout setae and fine, simple setae; C) tarsus relatively broad and short, length 4× width in middle part and length ca. 0.4× length of tibia; D) claw with mostly three long subapical setae.
Holotype. Philippines • larva; Luzon, Mountain Province, Banaue, Sumigar, Sumigar stream; 03.x.1967; leg. M.L. Pescador; on slide;
Philippines • 80 larvae; Luzon, Ifugao, Banaue, Sumigar Bridge; 16°59'37"N, 121°02'51"E; 1700 m alt.; xi. 1997; leg. W. Mey; 3 on slides; GenBank MT873543; GBIFCH 00763652, 00592354, 00515336; MZL; 34 in alcohol; GBIFCH 00515509, 00515516, 00515507, 00515513; MZL; 1 on slide; GenBank MT873545; GBIFCH 00763656; AdMU; 42 in alcohol; GBIFCH 00515512, 00515511, 00515471, 00515508; AdMU • 27 larvae; Luzon, Mountain Province, Bauko, mineral rich mountain creek; 17°03'53"N, 120°05'10"E; 1820 m alt.; xi. 1997; leg. W. Mey; 1 on slide; GBIFCH 00592353; AdMU; 16 in alcohol; GBIFCH 00515517; AdMU; 2 on slides; GenBank MT873541; GBIFCH 00763644, 00592367; MZL; 8 in alcohol; GBIFCH 00515510, 00515470, 00515506; MZL; • 12 larvae; Luzon, Ifugao, Tinoc; 16°40'58"N, 120°56'59"E; 1400 m alt.; xi. 1997; leg. W. Mey; 7 in alcohol; GBIFCH 00515514, 00515515; AdMU; 1 on slide; GenBank MT873544; GBIFCH 00763653; MZL; 4 in alcohol; GBIFCH 00515524; MZL.
Larva. (Figs
Colouration (Fig.
Head. Antenna (Figs
Labrum (Fig.
Right mandible (Fig.
Left mandible (Fig.
Both mandibles with lateral margins convex. Dorsally with fine, simple setae scattered over basal surface and mediolaterally with patch of long, spine-like, simple setae.
Hypopharynx and superlinguae (Fig.
Maxilla (Fig.
Labium (Fig.
Thorax. Hind protoptera (Fig.
Foreleg (Figs
Abdomen. Tergites (Fig.
Gills (Fig.
Paraproct (Fig.
Protogonostyli (Fig.
Philippines: Luzon (Fig.
The specimens were collected in mountain creeks at altitudes from 1400 m to 1820 m, mainly on bottom gravel or on rock surface in runs or riffles. They ocurred together with Labiobaetis sumigarensis (Müller-Liebenau, 1982), L. acei Kaltenbach, Garces & Gattolliat, 2020 and L. aldabae Kaltenbach, Garces & Gattolliat, 2020 (see also
Larva. The following characters distinguish P. realonae comb. nov. from P. luzonensis comb. nov.: A) abdominal tergite IV with triangular spines at posterior margin; B) tarsus dorsal margin with fine, simple setae; C) tarsus relatively slender and long, length 6.5× width in middle part and length ca. 0.5× length of tibia; D) claw with two long subapical setae.
Paratype. Philippines • larva; Luzon, Laguna, College, rapids in Molawin Creek; 28.vii.1977; leg. C.R. Realon; on slide;
Philippines • 10 larvae; Luzon, Ilocos Sur, Cervantes Municipality, Losong Bridge; 16°59'06"N, 120°46'11"E; 700 m alt.; 16. iv. 2019; leg. H. Freitag, J. Garces and C.V. Pangantihon; 3 in alcohol; GBIFCH 00515505; AdMU; 1 on slide; GenBank MT873542; GBIFCH 00763650;
Larva. (Figs
Colouration (Fig.
Head. Antenna (Fig.
Labrum (Fig.
Philibaetis realonae comb. nov., larva morphology: a. Labrum; b. Setae of submarginal row (ventral view); c. Right mandible; d. Right prostheca; e. Left mandible; f. Left prostheca; g. Tuft of setae; h. Hypopharynx and superlinguae; i. Maxilla; j. Labium (left side: ventral view; right side: dorsal view); k. Posterolateral seta on ventral side of paraglossa.
Right mandible (Fig.
Left mandible (Fig.
Both mandibles with lateral margins convex. Dorsally with fine, simple setae scattered over basal surface and mediolaterally with patch of long, spine-like, simple setae.
Hypopharynx and superlinguae (Fig.
Maxilla (Fig.
Labium (Fig.
Thorax. Hind protoptera. Absent.
Foreleg (Figs
Abdomen. Tergites (Fig.
Gills (Fig.
Paraproct (Fig.
Protogonostyli (Fig.
Protogonostyli developing under cuticle of male last instar larvae: a. Philibaetis luzonensis comb. nov.; b. Philibaetis realonae comb. nov.; c. Labiobaetis type of folding, Labiobaetis pelingeni Kaltenbach, Garces & Gattolliat, 2020; d. Baetis type of folding, Baetis rhodani (Pictet, 1843).
The specimens were collected at altitudes of 30 m and 700 m, partly together with Labiobaetis molawinensis (Müller-Liebenau, 1982) (see also
Philibaetis gen. nov. obviously belongs to the family Baetidae, based on the developing turbinate eyes of late instar male larvae, the long, slender body shape, the larval Y-shaped frontal suture reaching ventrally to lateral ocelli (Fig.
Apart from the unique combination of characters as described in the diagnosis, the following characters differentiate Philibaetis gen. nov. from all other genera of Baetinae: labrum ventrally on lateral margin with long, simple, spine-like setae, on anterolateral margin with long, feathered setae and medially with long, bifid setae and a partial submarginal row of lanceolate setae (Figs
Most of the characters are not unique autapomorphies of Philibaetis gen. nov. as they can be found in other related or not related genera as well. However, none of these genera is sharing several of the characters and they always present other important differences, for example, Asiobaetodes Gattolliat, 2012, has a similar labrum, but not the additional submarginal row of setae on ventral side (
Müller-Liebenau described both species of Philibaetis gen. nov. (but previously assigned to Baetis) with one subapical seta only (
The interspecific genetic distance between the two species of Philibaetis gen. nov. is 17%–18% (K2P; Table
Intraspecific and interspecific genetic distances between sequences of the mitochondrial COI gene in the genus Philibaetis gen. nov. (Kimura 2-parameter; %).
Species | Specimens catalogue # | 1 | 2 | 3 | 4 | |
---|---|---|---|---|---|---|
1 | P. luzonensis comb. nov. | GBIFCH 00763644 | ||||
2 | GBIFCH 00763652 | 3 | ||||
3 | GBIFCH 00763653 | 3 | 0 | |||
4 | GBIFCH 00763656 | 3 | 0 | 0 | ||
5 | P. realonae comb. nov. | GBIFCH 00763650 | 17 | 18 | 17 | 18 |
So far, both P. luzonensis comb. nov. and P. realonae comb. nov. were found on Luzon only, but at very different altitudes (Table
Species | Locality | Altitude | GPS coordinates |
---|---|---|---|
P. luzonensis comb. nov. | Philippines: Luzon | 1820 m | 17°03'53"N, 121°05'10"E |
1700 m | 16°59'37"N, 121°02'51"E | ||
1400 m | 16°40'58"N, 120°56'59"E | ||
P. realonae comb. nov. | Philippines: Luzon | 700 m | 16°59'06"N, 120°46'11"E |
30 m | 14°09'53"N, 121°14'48"E |
The number of sampled localities and different habitats is still limited in the Philippines and there are large regions without any collection activities so far. Therefore, we may assume that the number of taxa will continue to increase with further collections in the future.
We sincerely thank Lars Hendrich (Zoologische Staatssammlung München,