Lynceus amplopedia, Shu & Sigvardt & Chen & Olesen & Rogers & Sanoamuang, 2019

Shu, Shusen, Sigvardt, Zandra M. S., Chen, Xiaoyong, Olesen, Jørgen, Rogers, D. Christopher & Sanoamuang, La-orsri, 2019, Ophiacantha scissionis Lee & Stöhr & Bae & Shin 2019, sp. nov., Zoological Studies 58 (28), pp. 1-16 : 3-13

publication ID	https://doi.org/ 10.6620/ZS.2019.58-28
persistent identifier	https://treatment.plazi.org/id/03AB410E-FFA4-FFCF-FF46-D78367EBBD1E
treatment provided by	Felipe
scientific name	Lynceus amplopedia
status

Treatment

Genus Lynceus Müller, 1776 View in CoL (Sensu Rogers and Olesen, 2016)

Lynceus amplopedia sp. nov. ( Figs. 1–8 View Fig View Fig View Fig View Fig View Fig View Fig View Fig View Fig ) urn:lsid:zoobank.org:act:B7291C7F-C41E-4310-9812-D8F4A9409094

Type locality: CHINA: Yunnan Province: Qiubei County: Tianxing Township: Longtao Village: Shuiyantang temporary pond, near Road No. S206; 23°55'36.13"N, 104°14'17.04"E, altitude 1553 m asl.

Type material: Holotype, male (KIZ-2015010). Allotype, female (KIZ-2015011). Paratypes: five males and five females ( KKU-CS 2015001), two males and two females, (NHMD-615845), 18 males and 23 females (KIZ-2015012-50). All collected 5 October 2015, by H. F. Yang from the type locality.

Etymology: The specific epithet amplopedia is a combination of the Latin “amplus”, meaning “wide”, and the Latin “ped”, meaning “foot”. It refers to the unique, explanate modifications of endites 4 and 5 in male thoracopods III and IV. The gender is feminine.

Specific Diagnosis: Both sexes: Rostrum bicarinate. Head in lateral view with anterior margin sinuate, compound eyes on an ocular tubercle and frontal setal fields in deep concavity ( Figs. 1 View Fig , 3 View Fig , 5 View Fig , 7 View Fig , 8 View Fig ).

Male: Left and right thoracopods asymmetrically modified. One side, termed ‘explanate modified side’ (usually left side, occasionally right), with endites 4, 5, and endopod explanate (thoracopods III and IV); exopod with 14–15 digitiform processes dorsomedially (thoracopods V and VI); broad muscular basis (thoracopods III – V). Opposite side, termed ‘spinose modified side’ (usually right side, occasionally left), with endite 4 with robust, specialized spines medially (thoracopods V and VI); endite 3 elongate protruding (thoracopod VI) broad muscular basis (thoracopod V). Clasper palm with two scale patches (one laterally, one posteriorly), clasper endopod (movable finger) with constriction near articulation, endite 5 (large palp) dorsoventrally flattened with dorsal sulcus bearing setae ( Figs. 1–6 View Fig View Fig View Fig View Fig View Fig View Fig ).

Female: Rostrum distal margin broadly rounded and smooth, lacking serrations or lateral spines. Lamina abdominalis with four dorsal extensions and three marginal extensions ( Figs. 1 View Fig , 7 View Fig , 8 View Fig ).

Description: Male: Length range: 5.9–6.8 mm ( Figs. 1A View Fig , 3A, B View Fig ). Head ( Figs. 1B View Fig , 3B, E View Fig , 5C View Fig ) ~0.50 of body length. Occipital condyle round. Head anterior margin sinuate in lateral view, with three protrusions along rostrum: dorsal most the ocular tubercle, the second just distad to the setal fields (setal fields in deep concavity), and distal most approximately mid-length of rostrum. Dorsal organ oval, elongate, near occipital condyle. Compound eye sub-circular. Setal fields smaller than compound eyes, circular, with short dense setae, separated by rostral carinae proximal ends ( Figs. 1B, C View Fig , 3D View Fig , 5A View Fig ).

Rostrum ( Figs. 1C View Fig , 3D View Fig , 5A, B View Fig ) with two medial carinae, extending distally from near setal fields. Carinae parallel in proximal third, diverging approximately 20° at distal two thirds, terminating before rostral apex. Rostrum truncate with acute apicolateral corners. Truncated rostral distal margin shallowly, evenly concave, with dense row of setae, denticles absent ( Figs. 5A, B, D View Fig ). Rostral apex in lateral view dorsoventrally flattened distally ( Figs. 1B View Fig , 5D View Fig ). Rostrum in anterior view broadest at apicolateral corners with constriction approximately 50% of rostral length. Rostrum greatest width 1.2x rostral length. Fornices extending from second antenna insertion to apicolateral corners ( Figs. 1B View Fig , 3A, 3B View Fig ).

First antenna ( Fig. 5F View Fig ) with two antennomeres. Proximal antennomere cylindrical, length 2x breadth. Distal antennomere cylindrical, narrower than proximal antennomere, length 5.5x breadth, with two longitudinal rows of short sensory setae (or olfactory papillae).

Second antenna ( Fig. 5C View Fig ) biramous, long, extending to thoracopod VIII. Peduncle coxa cylindrical and thick, with longitudinal row of 8–10 long plumose setae on posterior margin. Peduncle basis with two groups of short, acute setae on anterior margin: two setae at middle ventral margin and six setae distally at exopod base. Exopod (anterior flagellum) with approximately 29 flagellomeres, each bearing a posterior long, distally directed, plumose seta and a short, acute, anterior seta present in most flagellomeres (absent in distal two flagellomeres and eight setae on proximal flagellomere anterior margin). Endopod (posterior flagellum) with approximately 34 flagellomeres, each bearing posterior, distally plumose seta (as exopod). Flagellomere setal length about half of corresponding flagellum.

Labrum large, lobiform, apex flat with fine setae.

Mandible ( Fig. 5E View Fig ) broad, molar surface with 13 or 14 transverse bispinose ridges with moderate indentation between spines. Posteriormost four ridges larger, with last three more broadly spaced than remaining ridges, posterior most ridge projecting as spine. Anterior most ridges smaller with spines, cluster of setae anteriorly.

Maxilla I ( Fig. 5C View Fig ) typical for genus, semicircular, with 11 plumose setae at medial margin, with three short denticles, robust setae at distal end, but lacking terminal setae of spines, posterior margin with fine setae. Maxilla II absent.

Carapace ( Figs. 1 A View Fig , 3 G View Fig ) semitransparent, relatively thin, smooth (lacking growth lines), globose and suboval in lateral view. Length <width, broadest near adductor muscle attachment site. Carapace with a slightly depressed region at end of posterior hinge line. Carapace average dimensions: height 6.9 mm, length 7.5 mm, width 4.5 mm (n = 10).

Thoracopods, 10 pairs, first pair modified as claspers ( Figs. 1D, E View Fig , 5H–N View Fig ). Thoracopods III – VI not bilaterally symmetrical ( Figs. 2 View Fig , 3C View Fig , 4 View Fig , 6 View Fig ). The modifications of one side are here termed “explanate modifications” due to the explanate shape of certain endites and the endopod (see below). The modifications of the opposing side thoracopods are here termed “spinose modifications” due to presence of greatly specialized spines on endite 4 (see below). In ~86% of specimens (19 of 22 specimens) the explanate modifications are on the left side thoracopods and the spinose modifications on the right side; in the remaining ~14% the pattern is opposite (n = 3 of 22 specimens, see below).

Thoracopod I ( Figs. 1D, E View Fig , 3F, H View Fig , 5H–N View Fig ) right and left clasper equal in size and shape. Endite 1 lobiform, elongate, margin with short setae and three pectinate spines. Endite 2 broadly transverse, margined with three setal types, (1) distal margin with ~50 long setae, each bearing dense, short setulae in distal half; (2) anterior surface submargin with ~40 short, smooth setae; (3) posterior surface submargin with ~20 long setae, each bearing sparse, long setulae in distal half. Endite 2 distal tenth slightly expanded, with six stout, long setae. Endite 3 (palm with gripping area) broadly transverse ( Fig. 5K View Fig ), length 1.5x width. Corm area 3 and 5 (sensu Kaji et al. 2014) covered with scales ( Fig. 5I, M, N View Fig ), medial margin with fine, type V setae (clasper setae types sensu Sigvardt and Olesen 2014). Gripping area with diverse setation: anterior margin with ~ 40 type IV setae ( Figs. 1D View Fig , 5H View Fig ), posterior margin with a row of ~seven long type I setae, a row of ~eight stout type II setae, and a group of six to eight type III setae ( Figs. 1E View Fig , 5I–K, N View Fig ). Endite 4 (small palp) digitiform, proximally expanded, length ~3x width, apex round, margined with ~15 long setae, endite 4 distal surface with four long setae, each bearing sparse, long setulae ( Figs. 1E View Fig , 5I View Fig ). Endite 5 (large palp) clavate, longer ~2x than endite 4, dorsoventrally flattened, proximal fifth arcuate, apex round, bearing ~20 simple setae; dorsal surface with sulcus with ~10–12 simple setae ( Fig. 5L View Fig ). Endopod (movable finger) digitiform, proximal fourth arcuate, diameter narrowing proximally distal to point of articulation, with sides diverging distally before apex ( Figs. 1D, E View Fig , 5H, K View Fig ). Endopod apex subacute, extending to one half of endite 3 medial surface. Clasper exopod elongate with setae along margin, mid-dorsal margin with three or four short, robust, spiniform setae, each with distal half bearing two rows of small denticles.

Thoracopod II not modified, endites 4 and 5 slightly expanded distally, digitiform.

Explanate modified side (holotype left side) ( Figs. 2 View Fig : ET 3- ET 6, 6A–C): Thoracopods III – V with greatly inflated, chitinous muscular bases. Thoracopod III endites 4 and 5 explanate; endite 4 length ~1.3x width, medial margin with sparse, long setae and apex with group of short setae; endite 5 length ~2x width, setae similar to endite 4 but apex with longer setae. Thoracopod IV endites 4, 5 and endopod explanate; endite 4 smaller than preceding endite 4, medial margin with long setae; endite 5 broadly ovate, medial margin with stout setae, apex with long setae; endopod subquadrate, medial margin with 12 stout setae and distally with four long, robust setae ( Figs. 2 View Fig , 6B View Fig ). Thoracopods V and VI endites 4, 5 and endopod slightly explanate, digitiform; exopod dorsomedial margin with 14–15 digitiform processes ( Figs. 2 View Fig , 4 View Fig : ET 5, ET 6; 6C), apex with long setae becoming shorter posteriorly ( Fig. 4 View Fig ).

Spinose modified side (holotype right side) ( Figs. 2 View Fig : 4ST5–ST6, 6D–G): Endites, endopod, and exopod of thoracopods II– IV of typical form for the genus. Thoracopod V with greatly inflated, chitinous muscular basis. Thoracopod V endite 4 digitiform, medial margin distal two third and apex with about 20 robust spines, each with two rows of small denticles in distal half. Thoracopod VI endite 3 protruding distally, elongate in similar way to endites 4, 5 and endopod; endite 3 distal half and endite 4 middle medial margin with characteristic stout spines, each with a broad apex turning backwards, with two parallel rows of strong denticles distally ( Figs. 4 View Fig , 6 View Fig ).

Thoracopods VII–X of typical form for the genus ( Martin and Belk 1988; Olesen et al. 2016).

Opercular lamella ( Figs. 1F View Fig , 5G View Fig ) cordate, flattened, cleft medially, lobes separated by one third their width. Each lobe and ventral lateral surface margined with short dense setae directed distomedially.

Telson ( Figs. 1G View Fig , 5G View Fig ) broad, ventral surface with dense, fine pilosity. Dorsoposterior angles with spiniform cercopod. Dorsal lobes rounded, each terminating with a long filiform telsonal filament, base of telsonal filament with short fine setae, respectively.

Female: Length range: 4.5–5.3 mm ( Figs. 1J View Fig , 7A View Fig ). Head ( Figs. 1H View Fig , 7B View Fig , 8B View Fig ). Head anterior margin in lateral view sinuate as in male, compound eyes on most prominent protrusion and setal fields placed in deepest concavity ( Figs. 7A, B View Fig , 8B View Fig ). Compound eyes proportionally smaller than in male ( Fig. 7C View Fig ). Rostrum ( Figs. 1I View Fig , 7C View Fig , 8A View Fig ) elongate, length about 2x distance from eyes to rostral constriction. Rostrum with two medial carinae extending distally from near setal fields. Carinae parallel in proximal half, diverging approximately 20° at distal half, extending towards rostral corners, terminating relatively far from apex. Rostral apex broadly rounded, smooth, apicolateral corners and denticulation absent ( Figs. 1I View Fig , 8C View Fig ).

Antennae and mouthparts as in male ( Figs. 8E, F View Fig , H-K).

Carapace ( Figs. 1J View Fig , 7E View Fig ) in lateral view globose, smooth, thin, ovate. Carapace posteriodorsal margin sharply declivous, with distinct depressed region at posterior hinge line end. Carapace proportionately smaller than in male, average dimensions: height 6.5 mm, length 7.0 mm, width 4.4 mm (n = 10).

Thoracopods 12 pairs, unmodified, typical for genus. Thoracopod I endite 1 spine larger than in male. Endites 2 and 3 marginal setae short, dense and smooth, submarginal setae long and sparse, both with setulae, endites 4, 5 and endopod digitiform, with ventral marginal setae. Thoracopods II–VII serially homologous, with increasing number of short setae in endites 2 and 3, long seta shorter, endites 4 and 5 with scraping setae. Thoracopods VIII–XII, endites 4, 5 and endopod lobiform, without epipod. Thoracopods IX and X with modified exopods for carrying the eggs, with distodorsal curved lobe with fine setae.

Lamina abdominalis ( Figs. 1K View Fig , 7D View Fig , 8G View Fig ) broad, dorsal to posterior thoracopods, bearing four dorsal and three marginal extensions. Anterior dorsal extension longest, arcuate and hamulate, tapering towards apex and directed anteriorly. Medial two dorsal extensions similar to anterior dorsal extension, about 2/3 and half as long, respectively. Posterior dorsal extension broadly triangular, directed posteriorly. Anterior marginal extension digitiform, straight, apex round. Medial and posterior marginal extensions lamellar, triangular, medial extension broader than posterior. All marginal extensions directed anteriorly.

Telson as in male.

Ecology and habitat

The type locality (easternYunnan Province, China) is in a karst region. The pool fills with both rain water and ground water from an adjacent cave. The water temperature was 22°C during sampling and the anostracan, Streptocephalus sirindhornae Sanomuang et al., 2000 , and the spinicaudatan, Leptestheria kunmingensis Shu et al., 2015 were found co-occurring.

IUCN status

Lynceus amplopedia sp. nov. meets the IUCN criteria as a Critically Endangered (CR) species, with its occupancy area less than 10 km 2 (IUCN criteria B2). The species is known only from the type locality, and was collected during a survey in Qiubei County. This site is the only known location for Lynceus in Yunnan Province despite many years of survey (IUCN criteria B2a). In addition, the type locality is near farmland. Pollution and pesticide from local agriculture, and the fluctuation of subterranean water may decrease the quality of the habitat (IUCN criteria B2 b and c).