Research Article |
Corresponding author: Somsak Panha ( somsak.pan@chula.ac.th ) Academic editor: Samuel James
© 2017 Ratmanee Chanabun, Khamla Inkavilay, Somsak Panha.
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:
Chanabun R, Inkavilay K, Panha S (2017) New species of semi-aquatic freshwater earthworm genus Glyphidrilus Horst, 1889 from Thailand and Laos (Oligochaeta, Almidae). ZooKeys 672: 1-34. https://doi.org/10.3897/zookeys.672.10212
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Seven new species of semi-aquatic freshwater earthworms belonging to the genus Glyphidrilus Horst, 1889 are described from Thailand and Laos, Glyphidrilus nanensis Chanabun & Panha sp. n., G. satunensis Chanabun & Panha sp. n., G. chiangraiensis Chanabun & Panha sp. n., G. namphao Chanabun & Panha sp. n., G. sekongensis Chanabun & Panha sp. n., G. namdonensis Chanabun & Panha sp. n., and G. champasakensis Chanabun & Panha sp. n. The species are characterized by their external and internal morphological characteristics, as well as body sizes. Other morphological character differences between these seven species were also compared, and an identification key is provided. The relationships of the new species to congeners are discussed.
Almidae , earthworms, Glyphidrilus , Laos, southeast Asia, Thailand
The semi-aquatic freshwater earthworm genus Glyphidrilus Horst, 1889 has been known since the nineteenth century. The unique morphological characters of the expanded epidermis at approximately the clitellum position, called “wings”, and the absence of prostate glands, the rounded body with a posterior quadrangular shape and the long slender banana-like cocoons are prominent in Glyphidrilus. The semi-aquatic habitat between terrestrial and freshwater ecosystems of rivers, streams, canals, ponds, swamps or even in paddy rice systems are also consistent (
Most previous species were described with some illustrations in a format which was frequently poorly interpreted and insufficient in some species. However, in the recent descriptions and redescriptions of several species are mostly from Thailand, and some from Malaysia, Singapore, and Laos, these deficiencies have been corrected. The color images of both animals and habitats together with anatomical illustration details have made improvements in a new description format. The 19 newly described species reported bring the total number to 40 recognized Glyphidrilus species (
The behavior of animals has been observed, and it was noted that the worms leave their tail tips exposed near surface of their muddy habitats. While submerging they produce casts as do most earthworms (
The systematic and faunistic surveys of Glyphidrilus were conducted in the lower Mekong River basin both in Thailand and Laos (Fig.
Distribution map of the new Glyphidrilus species from Thailand and Laos. Numbers in the circles refer to localities of the new species. 1 Glyphidrilus nanensis sp. n. 2 Glyphidrilus chiangraiensis sp. n. 3 Glyphidrilus namphao sp. n. 4 Glyphidrilus sekongensis sp. n. 5 Glyphidrilus namdonensis sp. n. and 6 Glyphidrilus champasakensis sp. n.
The type series are deposited in the Chulalongkorn University, Museum of Zoology, Bangkok, Thailand (
The descriptions were made from observations under an Olympus SZX16 stereoscopic light microscope. The following external and internal morphological characters were investigated and recorded: body length and segment number; the positions of clitellum and clitellar wings, genital markings, intestinal origin, gizzard, spermathecae, hearts and seminal vesicles. Illustrations were made for the whole body segments and the external and internal characters. The body width and length were measured in both full adults and juveniles, and are presented as the range (min-max) and mean±one standard deviation (SD).
Comparative studies of Glyphidrilus type specimens were made at four natural history museums:
Anatomical abbreviations are as follows (
gm genital markings
he hearts
np nephridia
sc spermathecae
sv seminal vesicles
wi wings
Prostomium zygolobous. Body shape nearly circular in cross section in anterior part, and becoming quadrangular in posterior part or after clitellum. Anus dorsal or dorso-terminal. A longitudinal lamellar ridge at maturity from body wall on each side in bc, through several of the clitellar segments, which are called wings. Dorsal pores absent. Setae four pairs per segment. Clitellum annular. Genital apertures, all minute and superficial. Male pores inter-or intraclitellar. Spermathecal pores usually all behind the testis segments. Gizzard in VII or VIII sometimes extending into an adjacent segment. Calciferous glands absent. Seminal vesicles usually short, usually four pairs in IX–XII. Holonephridia. Nephrostomes single ducts avesiculate and without sphincters or caeca. Testis and funnels free in X and XI. Male ducts intramural. Ovaries fan shaped and with several egg strings. Ovisacs present or absent. Prostate glands absent and spermathecae without diverticulum (
Glyphidrilus weberi Horst, 1889. Type species by original designation in
Holotype: One adult (
A small sized earthworm with the clitellar wings on the lateral side of the body in XXIV, XXV, XXVI– XXVII, XXVIII, XXIX. Clitellum in XVII, XVIII–XXXIII, XXXIV. Female pores, male pores, and spermathecal pores not visible. Genital markings: paired or asymmetrical on aa in X, XI, XII, XIII, XIV and XXVIII, XXIX, XXX; paired or asymmetrical on bc in XV, XVI, XVII–XXIII, XXIV, XXV. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XV. Ovaries in XIII–XIV. Spermathecae between 13/14–17/18.
Dimensions: body length 78 mm, diameter 2.6 mm in segment VIII, 4.7 mm before the clitellar wing in segment XXIII, 4.2 mm after wing in segment XXX in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 241 segments. Body color pale brown with variations from red to pink at adjacent tissues of wing portion in different individuals of newly collected specimens. At posterior end dorsal surface considerably broader than the ventral. Clitellar wing on ventro-lateral part of clitellum in XXVI–XXIX, 3.6 mm in height, and 0.3 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XVII–XXXIII. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd = 1.0:0.6:1.3:0.6:1.4 in segment VIII and 1.0:0.6:1.5:0.6:1.5 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: paired on aa in XII–XIII, laterally paired or asymmetrical on bc in XVII–XXIV.
Septa 5/6–8/9 thicker than between other segments, 9/10–14/15 thick and 15/16 to the last segment thin. Gizzard small, globular in 7/8. Intestine enlarged from XV. Hearts, five pairs in VII–XI, first in VII and last in XI. A pair of holonephridia in each segment from segment XIII onwards. Seminal vesicles, four pairs in IX, X, XI, XII. Ovaries, two pairs in XIII–XIV. Testes free in X and XI. Prostate and accessory glands absent. Spermathecae sessile and diverticula absent, elongated oval or globular between 13/14–17/18, about 0.2–0.3 mm in diameter, two to ten on each side per segment.
Body lengths of adult (n = 49) and juvenile paratypes (n = 10). Adults ranged from 72–99 mm (85.2±19.0), with 186–257 segments. Juveniles ranged from 73–93 mm (82.3±7.5), with 186–251 segments. Wings in XXIV, XXV, XXVI–XXVII, XXVIII, XXIX, clitellum in XVII, XVIII –XXXIII, XXXIV. Genital markings: paired or asymmetrical on aa in X, XI, XII, XIII, XIV and XXVIII, XXIX, XXX; paired or asymmetrical on bc in XV, XVI, XVII–XXIII, XXIV, XXV.
The new species was found in the river banks of Nan River at Saklek, Phichit, north Thailand, which was covered with worm casts.
The species was named after the locality on the banks of the Nan River. This was the first time that the worm genus was ever recorded from near this river.
For a summary of the following comparisons please see Table
The comparison of characters among Glyphidrilus species from Thailand and Laos. The morphological characters of the species described are from type specimens and original description.
Species | Length (mm) | Segments | Cli. | Wi. | Gm. | He. | In. | Gi. | Sc. | Type locality | ||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Paired on bc | Paired on aa | Un paired on aa | ||||||||||
G. mekongensis | 125–224 | 223–382 | XIX–XXXVII, XXXVIII | XXIV–½XXXIII, XXXIII, XXXIV, ½XXXV | XXIII | absent | absent | VII–XI | XV | VIII | absent | Khong Chiam, Ubon Ratchathani, Thailand |
G. vangviengensis | 104–160 | 145–229 | XIX, XX–XXXV, XXXVI, XXXVII | XXIV, XXV–XXXI, XXXII | XVIII, XIX, XX, XXI–XXIV, XXXIII, XXXIV | XII–XIV, XV | absent | VII–XI | XVI | VIII | absent | Song River Veintiane, Laos |
G. yunnanensis | 123 | 139 | XVIII–XXXVIII | XXII–XXXII | XVII–XXI, XXXII–XXXIV | absent | absent | VII–XI | XVI | VIII | absent | Yunnan, China |
G. borealis | 66–90 | 180–284 | XIV, XVI, XVII–XXXI, XXXII, XXXIII, XXXIV, XXXV, XXXVI | XXI, XXII–XXVII, XXVIII, XXIX | XIII, XIV, XVI, XVII, XVIII–XXII, XXIII, XXVII, XXVIII, XXIX, XXX | absent | absent | VII–XI | XIII | 7/8 | 14/15–18/19 | Maeklang waterfall, Doi Inthanon National Park, Chiangmai, Thailand |
G. vangthongensis | 62–195 | 150–358 | XII, XIII, XIV, XV, XVI– XL, XLI, XLII | XXIV, XXV, XXVI–XXXI, XXXII | XIII, XIV–XXIV, XXV, XXVI, XXXI, XXXII, XXXIII | XII, XIII, XIV, XXX, XXXII, XXXIII, XXXIV, XXXV, XXXVI | absent | VII–XI | XIV | 7/8 | 12/13–18/19 | Sakulnothayan waterfall, Vangthong, Phitsanu lok, Thailand |
G. chaophraya | 113–138 | 325–414 | XX–XLIII, XLIV, XLV | XXIV, XXV–XXXII, XXXIII | XVI, XIX, XX–XXIII, XXXII, XXXIII | XII, XIII, XIV, XXXIV, XXXV, XXXVII, XXXVIII | absent | VII–XI | XV | VIII | 16/17–22/23 | Chao phraya River, Payuha kiri, Nakhonsawan, Thailand |
G. chiensis | 61–193 | 122–386 | XVII, XVIII–XXXIII, XXXIV, XXXV, XXXVI, XXXVII, XXXVIII | XXIII, XXIV, XXV, XXVI–XXIX, XXX, XXXI, XXXII | XV, XVI, XVII, XVIII, XIX–XX, XXI, XXII, XXIII, XXIV, XXX, XXXI, XXXIII | XI, XII, XIII, XIV, XXX, XXXII, XXXIII, XXXIV, XXXV, XXXVI | absent | VII–XI | XV | VIII | 12/13–18/19 | Rice filed at Thatoom, Mueang, Mahasa rakham, Thailand |
G. quadratus | 54–156 | 186–378 | XV, XVI, XVII, XVIII–XXXI, XXXII, XXXIII, XXXIV, XXXV, XXXVI | XXIII, XXIV–XXVIII, XXIX, XXX, XXXI | XIII, XV, XVI, XVII, XVIII, XIX–XXI, XXII, XXIII, XXX, XXXI | XI, XII, XIII, XIV, XXXI, XXXII, XXXIII, XXXIV | absent | VII–XI | XV | VIII | 12/13–17/18 | Kang Sapue, Phibonmang sahan, Ubon Ratchathani, Thailand |
G. huailuangensis | 50–91 | 131–228 | XII, XIII, XVI–XXXII, XXXIII | XXV, XXVI–XXX, XXXI | XVI–XXIV | XXXI | absent | VIII–XI | XIII | 7/8 | absent | Huailung waterfall, Najahlauy, Ubon Ratchathani, Thailand |
G. trangensis | 11+–63+ | 41+–153+ | XVII, XVIII–XXX | XXII, XXIII–XXVII, XXVIII | absent | absent | XVIII–XXI | VIII–XI | XVI | 8/9 | XVIII–XXI | Trang River, Nayong, Trang |
G. wararamensis | 18+–120 | 46+–279 | XI, XII, XIII–XXXIII, XXXIV, XXXV | XX, XXI–XXVI, XXVII | XIV, XV, XVII–XIX, XX, XXVII | absent | XI–XIII, XIV, XV, XVII, XVIII–XIX, XX, XXVIII, XXIX–XXX | VIII–XI | XIV | 6/8 | 13/14–17/18 | Stream near Wattham Wararam, Phanom, Suratthani |
G. kratuensis | 48–93 | 221–282 | XVIII–XXX, XXXI, XXXII | XXIII, XXIV–XXVIII, XXIX, XXX | XIV, XV, XVI, XVII, XVIII, XIX, XXII, XXIII, XXIV, XXIX, XXX | absent | XVII, XIX–XX, XXI, XXII, XXIII, XXX–XXXI, XXXII–XXXIV | VIII–XI | XIV | VIII | 14/15–17/18 | Kratu waterfall, Kratu, Phuket |
G. nanensis sp. n. | 72–99 | 186–257 | XVII, XVIII–XXXIII, XXXIV | XXIV, XXV, XXVI–XXVII, XXVIII, XXIX | XV, XVI, XVII–XXIII, XXIV, XXV | X, XI, XII, XIII, XIV, XXVIII, XXIX, XXX | absent | VII –XI | XV | 7/8 | 13/14–17/18 | Rice field near Nan River, Saklek, Phichit, Thailand |
G. satunensis sp. n. | 60+–131 | 156+–326 | XVII, XVIII–XXXII, XXXIII, XXXIV, XXXV | XXIV, XXV, XXVI–XXIX, XXX, XXXI | XVII, XVIII, XIX | absent | XVI, XVII, XVIII–XXII, XXIII, XXIV | VIII–XI | XVI | VII | 13/14–15/16 | Nong Prakpraya, Mueang, Satun, Thailand |
G. chiangraiensis sp. n. | 94–340 | 89–394 | XVII, XVIII, XIX, XX, XXI–XXXVI, XXXVII, XXXVIII, XXXIX | XXIII, XXIV–XXVI, ½XXVII, XXVII, ½XXVIII, XXVIII | XXI, XXII, XXIII, XXIV, XXVII, XXVIII, XXIX–XXXV | XII–XIV, XV, XVI |
absent | VII–XI | XVI | VIII | 15/16–20/21 | Mekong River at Wat Hatkai, Chiang khong, Chiangrai, Thailand |
G. namphao sp. n. | 64–122 | 190–320 | XVII–XXVI, XXIX | XVIII–XXIV | XII–XV, XXV, XXVI | XVII | absent | VII–XI | XVI | VIII | 13/14–16/17 |
Phao River Kamkerd, Bolikhamxai, Laos |
G. sekongensis sp. n. | 90–134 | 237–337 | XVI, XVII–XXXVI, XXXVII | XXV–XXXI | XVI, XVII–XXIV, XXXII | absent | absent | VIII–XI | XVI | VIII | 12/13–15/16 | Stream at Ban Kiang kong, Lamarm, Sekong, Laos |
G. namdonensis sp. n. | 90–139 | 183–259 | XIX, XX–XXXVI, XXXVII, XXXVIII | XXIV, XXV–XXVIII, XXX | XXII, XXIII, XXIV, XXVII, XXVIII–XXXIII | XIII, XIV | absent | VII–XI | XVI | VIII | 14/15–18/19 | Done River, Thakhek, Kham mouan, Laos |
G. champasakensis sp. n. | 167–301 | 248–424 | XIX, XX– XLIX, L, LI, LII | XXIII, XXIV–½XXXII, XXXII, XXXIII | XVII, XVIII, XIX–XXII, XXIII, XXIV, XXXII, XXXIII, XXXIV, XXXV | XII, XIII, XXXIII, XXXIV | absent | VII–XI | XVI | VIII | 14/15–19/20 | Mekong River at Ban Khonkhen, Champa sak, Laos |
Holotype: One adult (
Glyphidrilus satunensis sp. n. has the clitellar wings on the lateral side of the body in XXIV, XXV, XXVI–XXIX, XXX, XXXI. Clitellum in XVII, XVIII–XXXII, XXXIII, XXXIV, XXXV. Female pores, male pores and spermathecal pores not visible. Genital markings: unpaired on aa in XVI, XVII, XVIII–XXII, XXIII, XXIV; paired or asymmetrical on bc in XVII, XVIII, XIX. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XVI. Ovaries in XIII–XIV. Spermathecae between 13/14–15/16.
Dimensions: body length 131 mm, diameter 2.2 mm in segment VIII, 2.3 mm before the clitellar wing in segment XXIII, 2.4 mm after wing in segment XXX in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 326 segments. Body color pale brown with variations from red to pink at adjacent tissues of wing portion in different individuals of newly collected specimens. At posterior end dorsal surface considerably broader than the ventral. Clitellar wing on ventro-lateral part of clitellum in XXIV–XXIX, 2.5 mm in height, and 0.5 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XVII–XXXIII. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd = 1.0:0.5:1.5:1.0:1.5 in segment VIII and 1.0:0.5:1.5:0.5:2.0 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: unpaired on aa in XVII–XXII.
Septa 5/6–7/8 thicker than between other segments, 8/9–9/10 thick and 10/11 to the last segment thin. Gizzard small, globular in VII. Intestine enlarged from XVI. Hearts, four pairs in VIII–XI. A pair of holonephridia in each segment from segment XIII onwards. Seminal vesicles, four pairs in IX–XII. Ovaries, two pairs in XIII–XIV. Testes free in X and XI. Prostate and accessory glands absent. Spermathecae sessile and diverticula absent, elongated oval or globular between 13/14–15/16, about 0.2–0.3 mm in diameter, four to five on each side per segment.
Body lengths of adult (n = 22) and juvenile paratypes (n = 21). Adults ranged from 60+–131 mm (95.8 ± 24.5), with 156+–326 segments. Juveniles ranged from 62–129 mm (82.5 ± 22.1), with 166–323 segments. Wings in XXIV, XXV, XXVI–XXIX, XXX, XXXI, clitellum in XVII, XVIII–XXXII, XXXIII, XXXIV, XXXV. Genital markings: unpaired on aa in XVI, XVII, XVIII–XXII, XXIII, XXIV; paired or asymmetrical on bc in XVII, XVIII, XIX.
The new species was found at a pond in Satun, south Thailand.
The name “satunensis” is given in reference to the type locality, Satun.
See Table
Holotype: One adult (
Photographs showing the A Glyphidrilus chiangraiensis sp. n. and other earthworms casts B type locality of G. chiangraiensis sp. n. in the river banks of Mekong River at Wat Hatkai, Chiangkhong, Chiangrai, north Thailand, and C coloration of newly collected paratype (
43 adults (
Glyphidrilus chiangraiensis sp. n. has clitellar wings on the lateral side of the body in XXIII, XXIV–XXVI, ½XXVII, XXVII, ½XXVIII, XXVIII. Clitellum in XVII, XVIII, XIX, XX, XXI–XXXVI, XXXVII, XXXVIII, XXXIX. Female pores, male pores and spermathecal pores not visible. Genital markings: paired or asymmetrical on aa in XII–XIV, XV, XVI, paired or asymmetrical on bc in XXI, XXII, XXIII, XXIV and XXVII, XXVIII, XXIX–XXXV. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XVI. Ovaries in XIII–XIV. Spermathecae between 15/16–20/21.
Dimensions: body length 158 mm, diameter 3.0 mm in segment VIII, 4.0 mm before the clitellar wing in segment XXIII, 4.0 mm after wing in segment XXIX in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 282 segments. Body color pale brown with variations from red to pink at adjacent tissues of wing portion in different individuals of newly collected specimens. Clitellar wing on ventro-lateral part of clitellum in XXIV–XXVII, ½XXVIII, 3.7 mm and 4.0 mm in height, and 0.5 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XVII–XXXVIII. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd=2.0:1.0:2.0:1.0:2.0 in segment VIII and 2.0:1.0:2.0:1.0:2.5 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: paired on aa in XIV, laterally paired or asymmetrical on bc in XXIII and XXIX–XXXV.
Septa 5/6–8/9 thicker than between other segments, 9/10–13/14 thick and 14/15 to the last segment thin. Gizzard small, globular in VIII. Intestine enlarged from XVI. Hearts, five pairs in VII–XI, first in VII and last in XI. A pair of holonephridia in each segment from segment XIII onwards. Seminal vesicles, four pairs in IX, X, XI, XII. Ovaries, two pairs in XIII and XIV. Testis free in X and XI. Prostate and accessory glands absent. Spermathecae sessile and diverticula absent, small elongated oval or globular between 15/16–20/21, about 0.1–0.2 mm in diameter, three to twelve per segment on each side per segment.
Body lengths of adults (n = 283) ranged from 94–340 mm (155.42 ± 54.93), with 89–394 segments. Wings in XXIII, XXXIV–XXVI, ½XXVII, XXVII, ½XXVIII, XXVIII, clitellum in XVII, XVIII, XIX, XX, XXI–XXXVI, XXXVII, XXXVIII, XXXIX. Genital markings: paired or asymmetrical on aa in XII–XIV, XV, XVI, paired or asymmetrical on bc in XXI, XXII, XXIII, XXIV and XXVII, XXVIII, XXIX–XXXV.
The new species is known from the type locality in the river banks of Mekong River at Wat Hatkai, Chiangkhong, Chiangrai, north Thailand, and was found in several locations along the Mekong River and its tributaries in the northeast and north of Thailand at Buengkan, Loei, Nongkhai, and Chiangrai and in Chaiyaburi, Luangprabang, and Sanakham to Vientiane of Laos.
The species was named after Chiangrai, the locality name.
(see Table
Holotype: One adult (
Glyphidrilus namphao sp. n. is a small worm with the clitellar wings on the lateral side of the body in XVIII–XXIV. Clitellum in XVII–XXVI, XXIX. Female pores, male pores and spermathecal pores not visible. Genital markings: paired or asymmetrical on aa in XVII; paired or asymmetrical on bc in XII–XV and XXV, XXVI. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XVI. Ovaries in XIII–XIV. Spermathecae between 13/14–16/17.
Dimensions: body length 92 mm, diameter 3.1 mm in segment VIII, 4.2 mm before the clitellar wing in segment XVII, 4.2 mm after wing in segment XXV in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 269 segments. Body color pale brown with variations from red to pink at adjacent tissues of wing portion in different individuals of newly collected specimens. At posterior end dorsal surface considerably broader than the ventral. Clitellar wing on ventro-lateral part of clitellum in XVIII–XXIV, 3.5 mm in height, and 0.25 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XVII–XXIX. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd =1.5:0.5:1.5:0.5:2.0 in segment VIII and 1.5:0.5:1.5:0.5:2.5 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: paired on aa in XVII, laterally paired or asymmetrical on bc in XII–XV and XXV.
Septa 4/5–6/7 thicker than between other segments, 7/8–11/12 thick and 12/13 to the last segment thin. Gizzard small, globular in VIII. Intestine enlarged from XVI. Hearts, five pairs in VII–XI, first in VII and last in XI. A pair of holonephridia in each segment from segment XIII onwards. Seminal vesicles, four pairs in IX, X, XI, XII. Ovaries, two pairs in XIII and XIV. Testis free in X and XI. Prostate and accessory glands absent. Spermathecae sessile and diverticula absent, elongated oval or globular between 13/14–16/17, about 0.3–0.4 mm in diameter, two to seven on each side per segment.
Body lengths of adult (n = 4) and juvenile paratypes (n = 8). Adults ranged from 64–122 mm (89.7±20.8), with 190–320 segments. Juveniles ranged from 64–120 mm (98.3±17.6), with 193–311 segments. Wings in XVIII–XXIV, clitellum in XVII–XXVI, XXIX. Genital markings: paired or asymmetrical on aa in XVII; paired or asymmetrical on bc in XII–XV and XXV, XXVI.
The new species was found in the river banks of Phao River which was covered with worm casts.
The species was named after the Phao River, the type locality.
Glyphidrilus namphao sp. n. is different from G. vangviengensis Chanabun & Panha, 2011 reported from Song River Veintiane, Laos in different locations of wings in XXIV, XXV–XXXI, XXXII, longer clitellum in XIX, XX–XXXV, XXXVI, XXXVII and lacking spermathecae. It differs from G. nanensis sp. n. from Nan River at Saklek, Phichit, north Thailand by G. nanensis sp. n. having wings in XXIV, XXV, XXVI–XXVII, XXVIII, XXIX, a longer clitellum in XVII, XVIII–XXXIII, XXXIV, and spermathecae between 13/14–17/18. It is different from G. sekongensis sp. n. from Ban Kiangkong, Lamarm, Sekong, Laos in the locations of wings in XXV–XXXI, a longer clitellum in XVI, XVII–XXXVI, XXXVII, the genital markings paired or asymmetrical on bc in XVI, XVII–XXIV, XXXII, and spermathecae between 12/13–15/16. Glyphidrilus namphao sp. n. differs from G. chiangraiensis sp. n. from Mekong River at Wat Hatkai, Chiangkhong, Chiangrai, north Thailand in the locations of wings in XXIII, XXIV–XXVI, ½XXVII, XXVII, ½XXVIII, XXVIII, a longer clitellum in XVII, XVIII, XIX, XX, XXI–XXXVI, XXXVII, XXXVIII, XXXIX, and spermathecae between 15/16–20/21 (see Table
Holotype: One adult (
Glyphidrilus sekongensis sp. n. is a small sized earthworm with the clitellar wings on the lateral side of the body in XXV–XXXI. Clitellum in XVI, XVII–XXXVI, XXXVII. Female pores, male pores and spermathecal pores not visible. Genital markings: paired or asymmetrical on bc in XVI, XVII–XXIV and XXXII. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XVI. Ovaries in XIII–XIV. Spermathecae between 12/13–15/16.
Dimensions: body length 134 mm, diameter 2.4 mm in segment VIII, 2.3 mm before the clitellar wing in segment XXIV, 2.4 mm after wing in segment XXXII in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 329 segments. Body color pale brown with variations from red to pink on adjacent tissues of wing portions in different individuals of newly collected specimens. The posterior end on the dorsal surface is considerably broader than the ventral. Clitellar wing on ventro-lateral part of clitellum in XXV–XXXI, 4.0 mm in height, and 0.5 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XVI–XXXVII. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd = 1.0:0.3:1.0:0.5:1.3 in segment VIII and 1.8:0.8:1.3:0.6:1.5 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: laterally paired or asymmetrical on bc in XVI–XXIV, XXXII.
Septa 5/6–8/9 thicker than between other segments, 9/10–14/15 thick and 15/16 to the last others segment, 9/10–14/15 thick and 15/16 to the last segment thin. Gizzard small, globular in VIII. Intestine enlarged from XVI. Hearts, four pairs in VIII–XI, first in VIII and last in XI. A pair of holonephridia in each segment from segment XIII onwards. Seminal vesicles, four pairs in IX, X, XI, XII. Ovaries, two pairs in XIII and XIV. Testis free in X and XI. Prostate and accessory glands absent. Spermathecae sessile and diverticula absent, small elongated oval or globular between 12/13–15/16, about 0.1–0.3 mm in diameter, two to seven on each side per segment.
Body lengths of adult (n = 3) and juvenile paratypes (n = 11). Adults ranged from 90–134 mm (109.6 ± 12.2), with 237–337 segments. Juveniles ranged from 86+–130 mm (104.2 ± 14.0), with 209+–329 segments. Wings in XXV–XXXI, clitellum in XVI, XVII–XXXVI, XXXVII. Genital markings: laterally paired or asymmetrical on bc in XVI, XVII–XXIV, XXXII.
The new species was found in a stream at Ban Kiangkong, Lamarm, Sekong, Laos. Soils are slightly sandy mixed with black organic matter.
The species was named after Sekong, the type locality in Laos.
(see Table
Holotype: One adult (
Glyphidrilus namdonensis sp. n. is small sized earthworm with distinctly expanded tissues, the clitellar wings on the lateral side of the body in XXIV, XXV–XXVIII, XXX. Clitellum in XIX, XX–XXXVI, XXXVII, XXXVIII. Female pores, male pores and spermathecal pores not visible. Genital markings: medium paired or asymmetrical on aa in XIII, XIV; paired or asymmetrical on bc in XXII, XXIII, XXIV and XXVII, XXVIII–XXXIII. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XVI. Ovaries in XIII–XIV. Spermathecae between 14/15–18/19.
Dimensions: body length 92 mm, diameter 3.5 mm in segment VIII, 4.0 mm before the clitellar wing in segment XXIII, 4.0 mm after the wing in segment XXXI in the clitellar region; body cylindrical in the anterior part, quadrangular in transverse section behind clitellum. 216 segments. Body color pale brown with variations from red to pink in adjacent tissues of the wing portions in different individuals of newly collected specimens. Clitellar wing on ventro-lateral part of clitellum in XXIV–XXX, 5.0 mm in height, and 0.2 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XX–XXXVII. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd = 1.3:0.5:1.0:0.5:2.0 in segment VIII and 1.5:0.5:1.0:0.5:2.3 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: medium paired on aa in XIII, XIV, laterally paired or asymmetrical on bc in XXII, XXIII.
Septa 5/6–8/9 thicker than between other segments, 9/10–14/15 thick, and 15/16 to the last segment thin. Gizzard small, globular in VIII. Intestine enlarged from XVI. Hearts, five pairs in VII–XI, first in VII and last in XI. A pair of holonephridia in each segment from segment XII onwards. Seminal vesicles, four pairs in IX, X, XI, XII. Ovaries two pairs in XIII and XIV. Testis free in X and XI. Prostate and accessory glands absent. Spermathecae sessile and diverticula absent, small elongated oval or globular between 14/15–18/19, about 0.1–0.2 mm in diameter, two to thirteen on each side per segment.
Body lengths of adult (n = 23) and juvenile paratypes (n = 6). Adults ranged from 90–139 mm (121.9±25.9), with 183–259 segments. Juveniles ranged from 87–136 mm (103.3±17.4), with 185–223 segments. Wings in XXIV, XXV–XXVIII, XXX, clitellum in XIX, XX–XXXVI, XXXVII, XXXVIII. Genital markings: medium paired or asymmetrical on aa in XIII, XIV; paired or asymmetrical on bc in XXII, XXIII, XXIV and XXVII, XXVIII–XXXIII.
The new species was found only from the banks of Done River at Ban Namdone, Thakhek, Khammouan, Laos.
The species was named after the Done River.
Glyphidrilus namdonensis sp. n. is compared with other Glyphidrilus having spermathecae and a clitellum starting feom segment XIX. Glyphidrilus namdonensis differs from G. champasakensis sp. n. by the latter having longer wings in XXIII, XXIV–½XXXII, XXXII, XXXIII, longer clitellum in XIX, XX–XLIX, L, LI, LII, and spermathecae between 14/15–19/20 (see Table
Holotype: One adult (
Glyphidrilus champasakensis sp. n. is a large sized earthworm with distinct expanded tissues of the clitellar wings on the sides of the body in XXIII, XXIV–½XXXII, XXXII, XXXIII. Clitellum in XIX, XX– XLIX, L, LI, LII. Female pores, male pores and spermathecal pores not visible. Genital markings: medium paired or asymmetrical on aa in XII, XIII, XXXIII, XXXIV; paired or asymmetrical on bc in XVII, XVIII, XIX–XXII, XXIII, XXIV and XXXII, XXXIII, XXXIV, XXXV. Four pairs of seminal vesicles in IX–XII. Intestinal origin in XVI. Large ovaries in XIII–XIV. Spermathecae between 14/15–19/20.
Dimensions: body length 301 mm, diameter 5.0 mm in segment VIII, 5.0 mm before the clitellar wing in segment XXII, 5.0 mm after wing in segment XXXIII in clitellar region; body cylindrical in anterior part, quadrangular in transverse section behind clitellum. 424 segments. Body color pale brown with variations from red to pink at adjacent tissues of wing portion in different individuals of newly collected specimens. Clitellar wing on ventro-lateral part of clitellum in XXIII–XXXII, 10.0 mm in height, and 0.2 mm in width on both sides. Prostomium zygolobous. Dorsal pores absent. Clitellum annular in XIX– XLIX. Four pairs of setae per segment from II, setal formula aa:ab:bc:cd:dd = 2.0:1.0:2.0:1.0:3.0 in segment VIII and 2.0:1.0:2.0:1.0:2.5 in postclitellar segments. Female pores, male pores, and spermathecal pores not visible. Genital markings: medium paired or asymmetrical on aa in XIII, XXXIV, laterally paired or asymmetrical on bc in XIX–XXII and XXXIII, XXXIV.
Septa 4/5–8/9 thicker than between other segments others segment, 9/10–11/12 thick and 12/13 to the last segment thin. Gizzard small, globular in VIII. Intestine enlarged from XVI. Hearts, five pairs in VII–XI, first in VII and last in XI. A pair of holonephridia in each segment from segment XIV onwards. Seminal vesicles, four pairs in IX, X, XI, XII. Ovaries, two pairs in XIII and XIV. Testis free in X and XI. Prostate and accessory glands absent. Spermathecae sessile and diverticula absent, small elongated oval or globular between 14/15–19/20, about 0.1–0.3 mm in diameter, five to thirteen on each side per segment.
Body lengths of adult (n = 24) ranged from 167–301 mm (212.75 ± 42.15), with 248–424 segments. Wings in XXIII, XXIV–½XXXII, XXXII, XXXIII, clitellum in XIX, XX– XLIX, L, LI, LII. Genital markings: paired or asymmetrical on aa in XII, XIII, XXXIII, XXXIV; paired or asymmetrical on bc in XVII, XVIII, XIX–XXII, XXIII, XXIV and XXXII, XXXIII, XXXIV, XXXV.
The new species was found only on the banks of the Mekong River at Ban Khonkhen, Champasak, Laos.
The new species was named after Champasak, Laos, the type locality.
Here we compare Glyphidrilus champasakensis sp. n. to the species with spermathecae and a clitellum beginning from segment XIX. It differs from G. namdonensis sp. n. by G. namdonensis sp. n. having shorter wings in XXIV, XXV–XXVIII, XXX, and spermathecae between 14/15–18/19 (see Table
Semi-aquatic earthworms of the genus Glyphidrilus are widely recorded on the Asian and African continents. Recently, many species have been described from several ecotone areas in Thailand between freshwater and terrestrial habitats of many river basins, where the soil pH varies from neutral to basic at 7–7.5 (
The seven new species from Thailand and Laos presented in this paper range in size, with respect to the other Glyphidrilus members, from large to small, with G. champasakensis sp. n. being the longest and G. nanensis sp. n. the smallest. The other five species are almost of the same size, as shown in Table
Glyphidrilus chiangraiensis sp. n. from Mekong River at Wat Hatkai, Chiangkhong, Chiangrai, north Thailand, was found in many areas of the Mekong River and its tributaries from Thailand and Laos, at elevations from 101–385 meters, and co-existing with G. mekongensis Panha & Chanabun, 2012, Amynthas mekongianus (Cognetti, 1922), Amynthas sp., and Metaphire sp. The earthworms and cocoons were found in the soil when digging (Fig.
Glyphidrilus satunensis sp. n. was found at a pond, part of a wildlife sanctuary at Satun, south Thailand. It has a similar body size with another species described from nearby in the Malay Peninsula (
The four new species described from Laos, G. namphao sp. n., G. sekongensis sp. n., G. namdonensis sp. n., and G. champasakensis sp. n. live in different habitats. Glyphidrilus namphao sp. n. lives in Phao River the river near to the Namphao border between Laos and Vietnam at a higher elevation (525 meters) than the other three new species. Glyphidrilus sekongensis sp. n. lives in a stream located within an evergreen and mossy forest at Ban Kiangkong, Lamarm, Sekong; the forest is covers 70% of the area near the stream. The soils are slightly sandy and black with the accumulation of organic matter. Glyphidrilus namdonensis sp. n. lives in the sandy banks of the Don River, which is one of the branches of Mekong River at Thathek, Khammouan, Laos. Glyphidrilus champasakensis sp. n. is one of the new species along the Mekong River found at a soil depth of 20–40 cm, and has similar characteristics to two other new species (G. sekongensis sp. n. and G. namdonensis sp. n.).
The following key includes only the species most closely related to those described here. The basis for including the species covered in the key is the same as the basis for including previously described species for comparison in the Remarks sections. The remaining species of Glyphidrilus must be identified with other resources.
1 | Spermathecae absent | 2 |
– | Spermathecae present | 5 |
2 | Wings in XXII–XXXII, and clitellum in XVIII–XXXVIII | G. yunnanensis Chen & Xu, 1977 |
– | Wings from XXIV or XXV | 3 |
3 | Clitellum in XII, XIII, XVI–XXXII, XXXIII, wings in XXV, XXVI–XXX, XXXI | G. huailuangensis Chanabun & Panha, 2013 |
– | Clitellum from XIX or XX | 4 |
4 | Wings in XXIV–½XXXIII, XXXIII, XXXIV, ½XXXV, clitellum in XIX–XXXVII, XXXVIII, and intestine beginning from XV G. mekongensis Panha & Chanabun, 2012 | |
– | Wings in XXIV, XXV–XXXI, XXXII, clitellum in XIX, XX–XXXV, XXXVI, XXXVII and intestine beginning from XVI | G. vangviengensis Chanabun & Panha, 2011 |
5 | Heart in VII–XI | 6 |
– | Heart in VIII–XI | 15 |
6 | Wings in XVIII–XXIV, clitellum in XVII–XXVI, XXIX, and spermathecae between 13/14–16/17 | G. namphao sp. n. |
– | Wings beginning from XX | 7 |
7 | Gizzard beginning from 7/8 | 8 |
– | Gizzard beginning in segment VIII | 10 |
8 | Wings in XXI, XXII–XXVII, XXVIII, XXIX, clitellum in XIV, XVI, XVII–XXXI, XXXII, XXXIII, XXXIV, XXXV, XXXVI and spermathecae between 14/15–18/19 | G. borealis Chanabun & Panha, 2013 |
– | Wings beginning from XXIV or XXV or XXVI | 9 |
9 | Wings in XXIV, XXV, XXVI–XXXI, XXXII, clitellum in XII, XIII, XIV, XV, XVI–XL, XLI, XLII and spermathecae between 12/13–18/19 | G. vangthongensis Chanabun & Panha, 2013 |
– | Wings in XXIV, XXV, XXVI–XXVII, XXVIII, XXIX, clitellum in XVII, XVIII–XXXIII, XXXIV and spermathecae between 13/14–17/18 | G. nanensis sp. n. |
10 | Intestine beginning from XV | 11 |
– | Intestine beginning from XVI | 13 |
11 | Spermathecae between 12/13 | 12 |
– | Spermathecae between 16/17–22/23, wings in XXIV, XXV–XXXII, XXXIII and clitellum in XX–XLIII, XLIV, XLV | G. chaophraya Chanabun & Panha, 2013 |
12 | Wings in XXIII, XXIV, XXV, XXVI–XXIX, XXX, XXXI, XXXII, clitellum in XVII, XVIII–XXXIII, XXXIV, XXXV, XXXVI, XXXVII, XXXVIII and spermathecae between 12/13–18/19 | G. chiensis Chanabun & Panha, 2013 |
– | Wings in XXIII, XXIV–XXVIII, XXIX, XXX, XXXI, clitellum in XV, XVI, XVII, XVIII–XXXI, XXXII, XXXIII, XXXIV, XXXV, XXXVI and spermathecae between 12/13–17/18 | G. quadratus Chanabun & Panha, 2013 |
13 | Spermathecae begin from 14/15 | 14 |
– | Spermathecae between 15/16–20/21, wings in XXIII, XXIV–XXVI, ½XXVII, XXVII, ½XXVIII, XXVIII and clitellum in XVII, XVIII, XIX, XX, XXI–XXXVI, XXXVII, XXXVIII, XXXIX | G. chiangraiensis sp. n. |
14 | Wings in XXIV, XXV–XXVIII, XXX, clitellum in XIX, XX–XXXVI, XXXVII, XXXVIII and spermathecae between 14/15–18/19 | G. namdonensis sp. n. |
– | Wings in XXIII, XXIV–½XXXII, XXXII, XXXIII, clitellum in XIX, XX– XLIX, L, LI, LII and spermathecae between 14/15–19/20 | G. champasakensis sp. n. |
15 | Intestine beginning from XIV | 16 |
– | Intestine beginning from XVI | 17 |
16 | Wings in XX, XXI–XXVI, XXVII, clitellum in XI, XII, XIII–XXXIII, XXXIV, XXXV and spermathecae between 13/14–17/18 | G. wararamensis Chanabun & Panha, 2013 |
– | Wings in XXIII, XXIV–XXVIII, XXIX, XXX, clitellum in XVIII–XXX, XXXI, XXXII and spermathecae between 14/15–17/18 | G. kratuensis Chanabun & Panha, 2013 |
17 | Spermathecae intrasegmental in XVIII–XXI, wings in XXII, XXIII–XXVII, XXVIII and clitellum in XVII, XVIII–XXX | G. trangensis Chanabun & Panha, 2013 |
– | Spermathecae intersegmental in 12/13 or 13/14 | 18 |
18 | Wings in XXIV, XXV, XXVI–XXIX, XXX, XXXI, clitellum in XVII, XVIII–XXXII, XXXIII, XXXIV, XXXV and spermathecae between 13/14–15/16 | G. satunensis sp. n. |
– | Wings in XXV–XXXI, clitellum in XVI, XVII–XXXVI, XXXVII and spermathecae between 12/13–15/16 | G. sekongensis sp. n. |
This project was partly funded by Chulalongkorn University Graduate School Postdoctoral Project to RC, while most of the financial support was received from The Thailand Research Fund, The TRF Senior Research Scholar RTA 5880002 (2015–2018) to SP. This research was also partially funded by a grant from WCU-058-016-FW (Food and Water Research Cluster, Chulalongkorn University), Higher Education Research Promotion (HERP; Project Code 2559A15562001). We are grateful to Professor Peter K.L. Ng, Dr. Daren Yeo and Dr. Kelvin Tan (