A new genus and three new species of mangrove slugs from the Indo-West Pacific (Mollusca: Gastropoda: Euthyneura: Onchidiidae)
Dayrat, Benoît
Goulding, Tricia C.
Khalil, Munawar
Apte, Deepak
Bourke, Adam J.
Comendador, Joseph
Tan, Shau Hwai
European Journal of Taxonomy
2019
2019-02-22
500
1
77
4DRDR
Dayrat & Goulding
Dayrat & Goulding & Khalil & Apte & Bourke & Comendador & Tan
2019
[424,980,614,641]
Gastropoda
Onchidiidae
Paromoionchis
Animalia
Systellommatophora
49
50
Mollusca
species
boholensis
gen. et sp. nov.
urn:lsid:zoobank.org:act: 104C35EF-FBF9-4EC2-A5A8-89AC30009270 Figs 31–40
Etymology Paromoionchis boholensis gen. et sp. nov.is named after Bohol Island, where the typelocality is.
Material examined Holotype PHILIPPINES• holotype(28/18 [3288] mm); Bohol, Maribojoc; 09°43.645´N, 123°50.988´E; 15 Jul. 2014; station 193; small island at end of boardwalk, sandy mud and rocks in back of mangrove; PNM0 41266. Other material INDONESIA– Sulawesi•2spec.(35/22[2128]and37/20[2129]mm); Wori; 01°36.055´N, 124°51.730´E; 9 Mar. 2013; station 84; tall mangrove forest of Sonneratiaand Avicennia, with old logs; UMIZ0 0 141• 1 spec. (9/6 [2175] mm); Bahoi; 01°43.355´N, 125°01.232´E; 10 Mar. 2013; station 85; sand, small rocks and pieces of wood, near narrow coastal mangrove; UMIZ0 0 142• 1 spec. (20/13 [2199] mm); Tamperong; 01°41.513´N, 125°00.797´E; 12 Mar. 2013; station 87; muddy mangrove with small and dense Rhizophora; UMIZ0 0 143• 1 spec. (12/8 [2316] mm); Mantehang; 01°41.880´N, 124°46.741´E; 15 Mar. 2013; station 91; Sonneratiaat low intertidal and Rhizophoraat high intertidal; UMIZ0 0 144• 1 spec. (20/13 [2360] mm); Panikkiang Island; 04°21.730´S, 119°35.630´E; 25 Mar. 2013; station 94; Rhizophora, Avicennia, Sonneratiaand old logs; UMIZ0 0 145.– Ambon• 3spec. (40/25 [2849], 45/30 [2850] and 45/25 [2851] mm); Wai; 03°34.652´S, 128°19.526´E; 15 Feb. 2014; station 132; narrow band of old Avicenniatrees on sandy mud, old logs on ground; UMIZ 0 0 146.– Seram• 1spec. (45/28 [2884] mm); Piru; 03°04.072´S, 128°11.362´E; 19 Feb. 2014; station 136; Sonneratiamangrove next to fish market, next to beach of palms and ferns, with cattle roaming around; UMIZ 0 0 147.– Kei Islands• 2spec. (10/8 [2896] and 17/8 [2901] mm); Un; 05°38.273´S, 132°45.738´E; 23 Feb. 2014; station 137; Bruguieraand Rhizophora, some muddy areas and some with coral rubble; UMIZ 0 0 148• 2 spec. (15/10 [2903] and 18/8 [2911] mm); Un; 05°38.273´S, 132°45.738´E; 25 Feb. 2014; station 140; back of mangrove, on rocks, on mud, inside logs and under leaf litter; UMIZ 0 0 149• 3spec. (40/22 [3565], 30/20 [2935] and 40/22 [2937] mm); Fiditan; 05°35.957´S, 132°45.112´E; 28 Feb. 2014; station 144; rocks behind muddy Rhizophoramangrove; UMIZ 0 0 150. – Bali• 1 spec. (35/17 [3117] mm); Gilimanuk; 08°10.156´S, 114°26.652´E; 4 Apr. 2014; station 156; muddy mangrove with Rhizophoraand Avicenniatrees; UMIZ0 0 140.– Halmahera• 1 spec. (25/16 [5019] mm); Sofifi; 00°45.473´N, 127°35.897´E; 8 Mar. 2015; station 205; Sonneratiamangrove, with dense roots and hard mud; UMIZ0 0 151• 2 spec. (47/30 [5140] and 35/22 [5146] mm); Gamkonora; 01°26.911´N, 127°31.625´E; 21 Mar. 2015; station 219; mostly Rhizophoramangrove with some sandy areas and some open muddy spaces; UMIZ0 0 152. Fig. 31. Paromoionchis boholensis gen. et sp. nov., unit #1, live animals. A. Holotype, dorsal view, 28 mmlong [3288], Philippines, Bohol( PNM 041266). B. Dorsalview, 26 mmlong [3609], Philippines, Luzon ( PNM 041267). C. Dorsalview, 38 mmlong [3417], Philippines, Bohol( PNM 041270). D. Dorsalview, 17 mmlong [3283], Philippines, Bohol( PNM 041268). E. Dorsalview, 30 mmlong [3372], Philippines, Bohol( PNM 041269). F. Dorsalview, 17 mmlong [3619], Philippines, Bohol( PNM 041268). G. Ventralview, same as E. H. Ventralview, 38 mmlong [3422], Philippines, Bohol( PNM 041270). I. Ventralview, 32 mmlong [3413], Philippines, Bohol( PNM 041270). J. Ventralview, same as C. Fig. 32. Paromoionchis boholensis gen. et sp. nov., unit #2, live animals. A. Dorsal view, 37 mmlong [2129], Indonesia, Sulawesi(UMIZ 00141). B. Dorsal view, 45 mmlong [2851], Indonesia, Ambon(UMIZ 00146). C. Dorsal view, 35 mmlong [3117], Indonesia, Bali(UMIZ 00140). D. Dorsal view, 18 mmlong [2911], Indonesia, Kei (UMIZ 00149). E. Dorsal view, 40 mmlong [2937], Indonesia, Kei (UMIZ 00150). F. Dorsal view, 15 mmlong [2903], Indonesia, Kei (UMIZ 00149). G. Ventral view, 45 mmlong [2884], Indonesia, Seram (UMIZ 00147). H. Ventral view, same as B. I. Ventral view, 45 mmlong [2850], Indonesia, Ambon(UMIZ 00146). J. Frontal view, 17 mmlong [2901], Indonesia, Kei (UMIZ 00148). PHILIPPINES– Luzon• 1 spec. (25/18 [3609] mm); Lian, Batangas; 13°58.130´N, 120°37.471´E; 5 Jul. 2014; station 179; narrow and impacted mangrove of Avicennianear village, very sandy, little to no mud; PNM0 41267. – Bohol• 2 spec. (16/9 [3283] and 17/10 [3619] mm); same data as for holotype; PNM0 41268• 3 spec. (20/15 [3369], 35/18 [3372] and 27/20 [3411] mm); Mabini; 09°51.586´N, 124°34.155´E; 18 Jul. 2014; station 196; open Avicenniaand Sonneratiaforest with sand, algae and coral rubble; PNM0 41269• 5 spec. (30/22 [3412], 30/23 [3413], 40/17 [3417], 40/20 [3422] and 42/25 [3423] mm); Maribojoc; 09°44.280´N, 123°49.389´E; 20 Jul. 2014; station 202; uplifted coral rubble with sand and algae, near Sonneratiatrees; PNM0 41270.
Color and morphology of live animals( Figs 31–32) Live animals are often covered with mud, in which case their dorsal color can hardly be seen. In unit #1, the background of the dorsal notum is brown, occasionally mottled with darker or lighter areas, while in unit #2 it ranges from very light brown (almost white) to dark brown, mottled or not. In some animals, there is a reddish hue on the margin of the dorsal notum (unit #1). In addition, in most animals the tip of the dorsal papillae (with and without dorsal eyes) can be bright yellow. The foot is orange (unit #1) or varies from gray to yellow and orange (unit #2). The hyponotum is also orange, often with a darker ring on the margin which may be bright red (unit #1) or homogenously gray, yellow, or orange, but can also display a mix of two or three of those colors (unit #2). The color of both the foot and the hyponotum of an individual can change very rapidly, especially when disturbed. The ocular tentacles are reddish brown and may or may not be speckled with white dots, like the head. The ocular tentacles are short (just a few millimeters long). Fig. 33. Paromoionchis boholensis gen. et sp. nov., unit #1, holotype, Philippines, Bohol[3288] (PNM 041266). A. Digestive system. B. Posterior hermaphroditic (female) reproductive system. C. Male copulatory organs. Abbreviations: ag = accessory penial gland; dd = deferent duct; ddg = dorsal lobe of digestive gland; fgm = female gland mass; hd = hermaphroditic duct; hg = hermaphroditic gland; i = intestine; ms = muscular sac (of accessory penial gland); ov = oviduct; pdg = posterior lobe of digestive gland; ps = penial sheath; r = rectum; rm = retractor muscle; rs = receptaculum seminis; sp = spermatheca; st = stomach; v = vestibule. Scales = 2 mm. Digestive system( Figs 33A, 34A, 35–36) Radulae measure up to 4.5 mm(unit #1) and 4 mm(unit #2) in length. Examples of radular formulae are presented in Table 4. Fig. 34. Paromoionchis boholensis gen. et sp. nov., unit #2, Indonesia, Bali[3117] (UMIZ 00140). A. Digestive system. B. Posterior hermaphroditic (female) reproductive system. C. Male copulatory organs. Abbreviations: ag = accessory penial gland; dd = deferent duct; ddg = dorsal lobe of digestive gland; fgm = female gland mass; hd = hermaphroditic duct; hg = hermaphroditic gland; i = intestine; ms = muscular sac (of accessory penial gland); ov = oviduct; pdg = posterior lobe of digestive gland; ps = penial sheath; r = rectum; rm = retractor muscle; rs = receptaculum seminis; sp = spermatheca; st = stomach; v = vestibule. Scales: A–B = 2 mm; C = 3 mm. Fig. 35. Paromoionchis boholensis gen. et sp. nov., unit #1, radula, Philippines, Bohol[3372] (PNM 041269). A. Rachidian and innermost lateral teeth. B. Lateral teeth with rachidian teeth. C. Lateral teeth. D. Outermost lateral teeth. Scales: A = 20 μm; B, D = 30 μm; C = 50 μm. Fig. 36. Paromoionchis boholensis gen. et sp. nov., unit #2, radula, Indonesia, Ambon[2851] (UMIZ 00146). A. Rachidian and innermost lateral teeth. B. Lateral teeth with rachidian teeth. C. Lateral teeth. D. Outermost lateral teeth. Scales: A, D = 30 μm; B–C = 50 μm. Fig. 37. Paromoionchis boholensis gen. et sp. nov., unit #1, spine of accessory penial gland. A. Holotype, Philippines, Bohol[3288] ( PNM 041266). B. Philippines, Bohol[3372] ( PNM 041269). C. Distaltip of spine, same as B. Scales: A–B = 100 μm; C = 10 μm. Fig. 38. Paromoionchis boholensis gen. et sp. nov., unit #2, spine of accessory penial gland. A. Indonesia, Bali[3117] (UMIZ 00140). B. Indonesia, Kei [2911] (UMIZ 00149). C. Tip of spine, Indonesia, Ambon[2851] (UMIZ 00146). D. Distal tip of spine, same as B. E. Tip of spine, same as A. F. Tip of spine, Indonesia, Halmahera [5140] (UMIZ 00152). Scales: A–B = 200 μm; C–F = 30 μm. Reproductive system( Figs 33B–C, 34B–C, 37–38) The male anterior organs consist of the penial complex (penis, penial sheath, vestibule, deferent duct, retractor muscle) and the accessory penial gland (flagellum and hollow spine). The hollow spine of the accessory penial gland is narrow, elongated, slightly curved. Its base is conical. Its diameter is approximately 50 to 70 μm for most of its length and 100–130 μm at its base (unit #1) and approximately 70 to 80 μm for most of its length and 150–200 μm at its base (unit #2). Its length ranges from 1 mm([3288] PNM 0 41266, holotype) to 1.2 mm([3372] PNM 041269) in unit #1 and from 1.1 mm([5019] UMIZ 00151) and 1.3 mm([3117] UMIZ 00140) to 1.8 mm([2911] UMIZ 0 0 149, [5140] UMIZ 00152) in unit #2, and its shape does vary between individuals ( Fig. 38). The penial sheath is narrow and elongated. The retractor muscle is vestigial, i.e., with its distal end being free in the visceral cavity, with no clear insertion (unit #1), or absent or vestigial (unit #2). The deferent duct is highly convoluted, with many loops. Inside the penial sheath, the penis is a narrow, elongated, soft, smooth (no hooks) and hollow tube of approximately 200 μm in diameter.
Distinctive diagnostic features Externally, the color of the foot and hyponotum can help one to identify Paromoionchis boholensis gen. et sp. nov., but unfortunately it is not fully reliable. Specimens with a bright orange foot and hyponotum are only found in P. boholensis gen. et sp. nov., especially in unit #1 but also in unit #2; the ventral side of P. tumidus, which is sympatric with P. boholensis( Fig. 6), can be orange but not bright orange. However, specimens with a more yellowish or greyish foot and hyponotum cannot be identified externally. The internal anatomy of P. boholensis gen. et sp. nov.(accessory penial gland, vestigial penial retractor muscle, penis with no hooks) is similar to that of P. daemelii. However, P. boholensis gen. et sp. nov.and P. daemeliido not overlap geographically, at least based on the present data. Thus, within its distribution range P. boholensis gen. et sp. nov.is the only species with this combination of internal characters. Indeed, the internal characters of the two species of Paromoionchis gen. nov.with which P. boholensis gen. et sp. nov.is sympatric ( P. goslineri gen. et sp. nov.and P. tumidus) are different ( Table 3). It must be noted that the known distribution of species of Paromoionchis gen. nov.may change as new records are found in the future and so the use of geographic data should only be used with caution for identification.
Distribution( Fig. 6) Philippines(unit #1): Bohol( typelocality), Luzon. Indonesia(unit #2): Ambon, Bali, Halmahera, Kei Islands, Seram, Sulawesi.
Habitat( Figs 39–40) Unit #1 of Paromoionchis boholensis gen. et sp. nov.is found on sandy mud or sand with very little mud, in mangroves or near mangrove trees and is rare (it was found at only four stations). Unit #2 is found in open or dense mangroves, on soft or hard mud, as well as on muddy sand and is common (but not as common as P. tumidusunit #1).
2005634536
2014-07-15
PNM
Philippines
9.727417
Maribojoc
1
123.8498
49
50
1
Bohol
holotype
2005634530
2013-03-09
UMIZ
Indonesia
1.6009166
Wori
1
124.86217
49
50
1
Sulawesi Utara
2005634528
2013-03-10
UMIZ
Indonesia
1.7225833
Bahoi
1
125.02053
49
50
1
Sulawesi Utara
2005634521
2013-03-12
UMIZ
Indonesia
1.6918833
Tamperong
1
125.01328
49
50
1
Sulawesi Utara
2005634534
2013-03-15
UMIZ
Indonesia
1.698
Mantehang
1
124.779015
49
50
1
Sulawesi Utara
2005720719
2013-03-25
UMIZ
Indonesia
-4.362167
Ambon
1
119.593834
Panikkiang Island
49
50
1
Sulawesi Utara
2005720714
narrow band of old Avicennia trees on sandy mud, old logs on ground
2014-02-15
UMIZ
Indonesia
-3.5775332
station 132
1
128.32544
Wai
49
50
0 0 146
3
Ambon
2005720716
Sonneratia mangrove next to fish market, next to beach of palms and ferns, with cattle roaming around
2014-02-19
UMIZ
Indonesia
-3.0678666
station 136
1
128.18936
Piru
49
50
1, 0 0 147
1
Seram
2005720717
Bruguiera and Rhizophora, some muddy areas and some with coral rubble
2014-02-23
UMIZ
Indonesia
-5.637883
Un
1
132.7623
49
50
0 0 148
2
Kei Islands
2005634543
back of mangrove, on rocks, on mud, inside logs and under leaf litter
2014-02-25
Key Island
UMIZ
Indonesia
-5.637883
Un
1
132.7623
49
50
0 0 149
1
Sulawesi Utara
2005634538
rocks behind muddy Rhizophora mangrove
2014-02-28
UMIZ
Indonesia
-5.599283
Fiditan
1
132.75186
49
50
0 0 150
3
Sulawesi Utara
2005720722
2014-04-04
UMIZ
Indonesia
-8.169267
Halmahera
1
114.4442
Gilimanuk
49
50
1
Bali
2005720733
2015-03-08
UMIZ
Indonesia
0.7578833
Sofifi
1
127.59828
49
50
1
Bali
2005634525
2015-03-21
UMIZ
Indonesia
1.4485166
Gamkonora
1
127.527084
49
50
1
Bali
2005634509
PNM
B. Dorsal & C. Dorsal & D. Dorsal & E. Dorsal & F. Dorsal & G. Ventral & E. H. Ventral & I. Ventral & J. Ventral
Philippines
Bohol
50
51
PNM 041266, PNM 041267, PNM 041270, PNM 041268, PNM 041269
1
Bohol
holotype
2005634532
2014-07-05
PNM
Philippines
13.968833
Lian
1
120.62452
52
53
1
Batangas
2005634531
2014-07-15
PNM
Philippines
9.727417
Maribojoc
1
123.8498
52
53
1
Bohol
2005634544
2014-07-18
PNM
Philippines
9.859767
Mabini
1
124.56925
52
53
1
Bohol
2005634541
2014-07-20
PNM
Philippines
9.738
Maribojoc
1
123.82315
52
53
1
Bohol
2005634539
PNM
C. Distal & B. Scales
Philippines
Bohol
55
56
PNM 041266, PNM 041269
1
Bohol
holotype