1. science
2. geology

Journal of Earth Science, Vol. 26, No. 2, p. 192–202, April 2015
Printed in China
DOI: 10.1007/s12583-015-0525-z
ISSN 1674-487X
Exceptionally Preserved Caddisfly Larval Cases
(Insecta) from the Lower Cretaceous of the Liupanshan
Basin, Western China
Xin He1, 2, Zhong-Qiang Chen*1, Zongsheng Lu1, Jun Li3, Wei Hu3, Shengfu Li2, Zhitao Xu2
1. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, China
2. Guangxi Geological Exploration Institute of China Metellurgical Geology Bureau, Nanning 530000, China
3. School of Earth Sciences and Graduate School, China University of Geosciences, Wuhan 430074, China
ABSTRACT: Abundant well-preserved tubular fossils of caddisfly (Insecta: Trichoptera) larval cases
are reported from the Early Cretaceous Madongshan and Naijiahe formations of the Liupanshan Basin,
Ningxia Province, western China. Most cases were mainly preserved in life position and densely packed
in various layers. Individual cases in each layer tended to be same in size and were erect and parallel to
one another and open at both ends. In a transverse section cut perpendicular to the long axis of the
cases, individual case appears to form a rounded ring. Small cases are elliptic in a cross-section oblique
to the long axis of the cases. Tube walls are nearly subparallel to one another in longitudinal section
with both ends being open. The caudal end of the case slightly tapers and usually points downward. The
cases were closely packed, almost touching with one another and lacking bifurcate or connecting structure. The overwhelming majority of cases were partially or fully filled with calcite. The case wall embraces a medium particle layer flanked by inner and outer organic layers. Individual particles are ovate
in outline and comprise cryptocrystalline or ganic pellets. SEM imaging shows that those pellets are
sub-cylindrical in outline and elliptic in cross section, and are made primarily of calcium carbonate. All
features observed justify the assignment of the Liupanshan caddisfly cases to ichnogenus Coprindusia.
The extinct insect Ningxiapsyche fangi was found in association with the Liupanshan caddisfly larval
cases, and thus could be the candidate of the potential trace-maker.
KEY WORDS: caddisfly larval case, tube wall microstructure, Early Cretaceous, Liupanshan Basin,
western China.
0
INTRODUCTION
Both the Trichoptera and Lepidoptera of the Ampliesmenoptera are most distinct among the holometabolous insects
(Huang et al., 2009; Kjer et al., 2001). They are also the second
largest lineage of aquatic insects (Gallego et al., 2011). Compared with extremely diverse extant Trichoptera, which contains 13 574 species of 608 genera belonging to 47 families,
fossil Trichoptera is much less diverse and includes 680 species,
127 genera and 12 families. The larval and pupal stages of extant Trichoptera caddisflies are mainly aquatic and widespread
in all freshwater ecosystems ranging from mountain streams,
ponds, large rivers, lakes, wetlands, and even brackish water,
while the adults inhabit mostly terrestrial environments (Daniel
et al., 2009; Moor and Ivanov, 2008; Greenwood et al., 2003).
Most caddisfly larvae obtain materials from the surrounding
*Corresponding author: [email protected]
© China University of Geosciences and Springer-Verlag Berlin
Heidelberg 2015
Manuscript received October 21, 2014.
Manuscript accepted January 20, 2015.
habitats to construct their tubular cases. Their portable cases
were attached as dwelling and protection in foraging food
(Brian et al., 2011; Boyero and Barnard, 2004; Williams and
Penak, 1980; Mackay and Wiggins, 1979).
Since Cockerell (1923) reported the first example, the fossil caddisfly cases have been reported from the Mesozoic and
Cenozoic strata worldwide. The known oldest fossil larval case
was found in Middle Jurassic (Huang et al., 2009; Ponomarenko et al., 2009; Ivanov and Sukatsheva, 2002), although
fossil caddisflies are known from the Permian. To date, total 13
ichnogenera have been proposed to accommodate fossil larval
cases based on their various morphologies, including Conchindusia, Piscindusia, Ostracindusia, Pelindusia, Terrindusia,
Molindusia, Folindusia, Secrindusia, Scyphindusia, Charindusia, Indusia, Coprindusia, and Tektonargus (Gallego et al.,
2011; Ponomarenko et al., 2009; Ivanov, 2006; Sukatsheva,
2005; Hasiotis et al., 1998; Jarzembowski, 1995; Lewis, 1970a,
b). The possible case-makers still remain disputed, although
several candidates have been proposed (Paik, 2005; Leggitt and
Cushman, 2001; Bradley, 1974). This is because no smoke-gun
organisms were captured in the cases. Moreover, the preliminary classification schemes have also proposed to describe the
wall components of those tubular cases (Boyero and Barnard,
He, X., Chen, Z. Q., Lu, Z. S., et al., 2015. Exceptionally Preserved Caddisfly Larval Cases (Insecta) from the Lower Cretaceous of
the Liupanshan Basin, Western China. Journal of Earth Science, 26(2): 192–202. doi:10.1007/s12583-015-0525-z
Exceptionally Preserved Caddisfly Larval Cases (Insecta) from the Lower Cretaceous of the Liupanshan Basin, Western China
2004; Loewen et al., 1999; Bradley, 1924). However, microstructures of caddisfly case walls still remain unclear.
More recently, we have obtained abundant, exceptionally
preserved caddisfly larval cases from the Liupanshan Basin,
Ningxia Province, western China (Fig. 1). Such well-preserved
larval cases not only provide additional examples of fossil caddisfly cases, but also enable us to insight into microstructure of
case walls, in particular, the arrangement pattern of cemented
pellets in medium layer of case wall. The latter characteristics
are crucial in ichnology of those fossil caddisfly cases.
1
GEOLOGICAL AND STRATIGRAPHIC SETTINGS
The studied larval cases were collected from the Lower
Cretaceous succession in the Yaoshan Section of the Liupanshan Basin, approximately 20 km northeast of the Tongxin
Town, eastern Ningxia Province, western China (Figs. 1 and
193
2a). The Liupanshan Basin (105°E–107°E, 34 40'N–37 10'N) is
a reverse triangular inland basin and located at the junction
among the Shaanxi, Gansu and Ningxia provinces, western
China (Fig. 1). Tectonically, the basin lies at the northeastern
margin of the Tibet-Qinghai Plateau and is bounded by the
Eerduosi Block in the east, the Alashan Block in the north, and
the Qilian-Qinling orogenic fold belt in the southwest (Tang et
al., 2004; Fu and Li, 2002), respectively. The lacustrine basin
was uplifted during the Yanshan orogeny of Late Jurassic age.
Since then, the Liupanshan Basin was filled with terrestrial
sediments of alluvial fan, deltaic, braided river, and lacustrine
facies of the Liupanshan Group, which comprises the Sanqiao,
Heshangpu, Liwaxia, Madongshan, and Naijiahe formations in
an ascending order (Zhou et al., 2005). Both palynology and
paleomagnetic correlation suggest an Early Cretaceous age for
this group (Dai et al., 2010, 2009; Li and Du, 2006).
Figure 1. Geographical map showing the location of the studied section in the Liupanshan Basin, Ningxia Province, western
China (left figure) and columnar section of the Lower Cretaceous succession showing fossil horizons.
Of these, the early Early Cretaceous Sanqiao and
Heshangpu formations are dominated by reddish coarse sandstone and conglomerate of alluvial fan and deltaic facies and
indicate the dry and hot sub-tropical temperate climatic conditions (Li and Du, 2006; Zhou e al., 2005). The Liwaxia Formation and lower Madongshan Formation of middle Early Cretaceous age are composed mainly of grey find sandstone and
mudstone of deltaic and lacustrine facies, indicating a relatively
warm, humid climatic condition (Zhou et al., 2005). The upper
Madongshan Formation and Naijiahe Formation of late Early
Cretaceous age consist chiefly of fine sandstone, mudstone and
dolomites and characterized by abundant pseudomorphs of
gypsum and halite, indicating high-evaporatic, dry climatic
condition (Jin and Cao, 2006). Climatic varations through the
Liupanshan Group are also reinforced by palynologic analysis.
The Liupanshan Group contains abundant spores Schizaeoisporites and pollens Ephedripites, Jugella, and Classopollis (Li
and Du, 2006; Liu, 1983), characteristics of hot, arid microfloral assemblages worldwide (Moor and Ivanov, 2008). The environmental and climatic inference of the Liupanshan Group is
also strengthened by organic carbon isotopic geochemistry (Bai
et al., 2003) and changes of chromaticity and magnetic suscep-
194
Xin He, Zhong-Qiang Chen, Zongsheng Lu, Jun Li, Wei Hu, Shengfu Li and Zhitao Xu
tibility (Dai et al., 2010, 2009), all of which indicate that the
Liupanshan Group successions were deposited in the dry and
hot sub-tropical temperate climatic conditions, as the similar
climatic conditions of most landmass in the world during that
times (Moor and Ivanov, 2008).
The caddisfly cases are preserved in several horizons between the upper Madongshan and basal Naijiahe formations (Fig.
2a). The former formation is a thick lacustrine siliciclasticcarbonate unit, resting conformably on the Liwaxia Formation
of Hauterivian-Barremian age and overlain by the Naijiahe
Formation which is characterized by evaporitic rocks of Albian
age (Dai et al., 2009; Shi et al., 2006; Liu, 1983). The
Madongshan Formation is dominated by mudstone in the lower
part and composed of mudstone, siltstone and marl, with minor
constituents of shale and calcareous mudstone in the upper part.
The upper Madongshan Formation yields caddisfly larval cases
at its basal part (beds 1–4; Fig. 1) and abundant fossils of ostracods, fishes, insects, plants, sporopollen, and conchostracans
in the rest parts of the formation (Li and Du, 2006; Zhang,
2004; Li, 1995; Qi, 1988; Liu, 1983). These faunal and floral
assemblages point collectively to an Early Cretaceous age (Li
and Du, 2006). Both lithofacies and paleoecologic analyses
indicate that the upper Madongshan Formation represents the
sedimentation of lacustrine setting. The basal Naijiahe Formation also yields caddisfly cases and comprises mudstone and
calcareous mudstone, from which Hong and Li (2004) reported
insect wing of Ningxiapsyche fangi of Aptian–Albian age
(Early Cretaceous).
All lines of evidence indicate that the Liupanshan caddisfly cases are Aptian–Albian (Early Cretaceous) in age.
Figure 2. Caddisfly case bioherms and taphonomy and morphologies of fossil caddisfly larval cases from the Lower Cretaceous of the Liupanshan Basin. (a) Caddisfly case bioherms on the outcrop (arrow indicated); (b) columnar colonies of caddisfly larval cases on the outcrop; (c) the planar structure of the caddisfly-dominated columns; (d) the autochthonous burial
caddisfly larval cases, scale bar: 5 mm; (e) close-up of the boxed area in D showing one complete larval case; (f) the allochthonous burial caddisfly larval cases, bar: 5 mm; (g) close-up of F showing tiny larval cases, scale bar: 1 mm.
Exceptionally Preserved Caddisfly Larval Cases (Insecta) from the Lower Cretaceous of the Liupanshan Basin, Western China
2
3
MATERIAL AND METHOD
Number of specimens
75
(a)
200
(b)
N=281
160
60
120
45
80
30
40
15
0
RESULTS
3.1 Taphonomy and Morphology of Caddisfly Larval Cases
3.1.1 Taphonomy
On the outcrop, the caddisfly larval cases were mainly
preserved in autochthonous and allochthonous burial states.
The autochthonously preserved cases are characterized by the
densely packed larval cases in various layers. Individual cases
in each layer were erect and parallel to one another and open at
both ends, exhibiting their life position (Fig. 2d). They appear
to have a narrow size range with case length varying from 11 to
15 mm. Of these, 70% individuals are 13–14 mm long (Fig. 3a).
Of 281 cases counted here, 75% individuals are 2.4–2.5 mm in
diameter (Fig. 3b). Thus, the in situ larval cases exhibit strong
size selectivity. In contrast, the allochthonously buried
Both individual and colonial caddisfly case samples have
been collected. Their taphonomic features were also observed
in the field. Both petrographic and scanning electron microscope (SEM) imaging analyses have been undertaken to probe
into microstructures of caddisfly case walls. Prior to observation under a Quanta 200 FEI SEM, cemented pellets of tube
walls were coated with 5–7 nm gold using a SCD 005
BAL-TEC auto sputter coater. Thin-section micrographs were
taken using a Nikon Eclipse E200 digital camera mounted on
an E200 POL Standard Set transmitted-light polarizing microscope.
N=135
0
1
3
5
7
9
11
13
1.0
15 17
1.5
2.0
2.5
Number of specimens
(c)
25
N=145
15
10
10
5
5
1
3
5
7
9
11
13
0
15 17
1.0
(e)
Number of specimens
N=113
20
15
100
3.0
(d)
25
20
0
195
N=280
250
1.5
2.0
2.5
3.0
(f)
N=394
200
80
60
150
40
100
20
50
0
1
3
5
7
9 11
Length (mm)
13
15 17
0
1.0
1.5
2.0
2.5
Diameter (mm)
3.0
Figure 3. Measurements of larval cases from the Liupanshan Group. (a) Lengths of the autochthonously preserved larval
cases; (b) diameters of the autochthonously preserved larval cases; (c) lengths of the allochthonously preserved larval cases;
(d) diameters of the allochthonously preserved larval cases; (e) lengths of all caddisfly larval cases; (f) diameters of all caddisfly larval cases.
Xin He, Zhong-Qiang Chen, Zongsheng Lu, Jun Li, Wei Hu, Shengfu Li and Zhitao Xu
196
larval cases have a much broader size range with case length
varying from 2 to 17 mm. Of these, the individuals having
10–11 mm in length are most frequently present, but only occupy 17.2% of all cases. Moreover, 13% individuals are 5–6
and 8–9 mm in length, respectively and 10% individuals are
9–10 mm and 13–14 mm in length, respectively (Fig. 3c). Of
113 cases counted here, 20% individuals are 2.5–2.6 mm in
diameter, but individuals having 2.0–2.1, 2.1–2.2, 2.3–2.4,
2.4–2.5, and 2.6–2.7 mm, respectively are also commonly present, each group occupying around 10% (Fig. 3d). Thus, the
allochthonously buried larval cases do not show any size preference. Furthermore, they were usually not orientated and randomly scattered on sediments, indicating transportation (Figs.
2f, 2g).
The single cases are usually coated by thin calcite laminae comprising microsparite. Single lamina is about 0.1 mm
thick. Blue-green algal mats, i.e., Girvanella (Fig. 4c) encrusted on surfaces of single larval cases to aggregate pellets,
shell fragments and small microbial encrusts, like the modern
counterparts (Fig. 4a) and aggregated single or colonial cases to
form caddisfly bioherms. Single caddisfly case, the overwhelming majority of larval cases were partially or fully filled
with sparite cement, microbial encrusts and pellets (Fig. 4b).
3.1.2
Morphology
Caddisfly cases usually colonized to build bioherm,
which is 3–5 m high. Caddisfly bioherms extend laterally up to
400–500 m, and thus are spectacular in the field (Fig. 2b). Each
bioherm comprises case columns, which were constructed by
4–6 layers of caddisfly cases. Individual columns, up to 2–
2.5 m in height, are cylindrical and slightly taper towards the
top in vertical outline (Fig. 2b). They are about 1 m in diameter
and dome-like in plan view (Fig. 2c). In the columnar colonies
the layered caddisfly cases are separated from one another by
thin lime laminae of possible microbial origin. Erect caddisfly
cases form case bands, which are parallel to bedding plane (Fig.
2d). Single caddisfly case-concentrating bands are 10–13 mm
thick, while single laminar layers are about 2 mm thick. The
incumbent caddisfly cases are scarce (Fig. 2e). In addition,
some caddisfly larval cases were dispersedly preserved in calcareous siltstones (Figs. 2f, 2g). Of the caddisfly cases observed herein, about 33% individual cases are 13–14 mm in
length and 60% cases are 2.4–2.5 mm in diameter (Figs.
3e–3f).
In a transverse section cut perpendicular to the long axis
of the case, individual case appears to be a rounded ring (Figs.
5d, 5f). In a cross-section oblique to the long axis of the case,
individual case is elliptic in outline (Figs. 5e, 5g). In the cross
section cut parallel to the long axis of the case, individual case
is characterized by two almost subparallel walls with both ends
being open (Fig. 5h). The caudal end of the tube often slightly
tapers and points downward (Figs. 5a–5b, 5h). The cases are
closely packed, open at two ends, nearly touching with one
another and lacking bifurcate or connecting structures.
3.1.3
Figure 4. (a) Modern caddisfly case with insect inside (after
Holzenthal et al., 2007), scale bar is 3 mm; (b) microphotograph in longitudinal section of larval case showing that
case inside is filled with sparite cement (sc), microbes (m),
and microbial encrusts (me), and that surfaces were encrusted by microbial mats (mm) (i.e., Girvanella), microbial
encrusts, pellets (p), and fossil fragments (sf), Scale bar is 1
mm.
Case wall microstructure and components
The case wall embraces a distinct three-layer architecture
with a medium particle layer being flanked by the inner and
outer layers, both of which comprise dark organic matters
(Figs. 4d–4h). The inner dark organic layer is discontiguous,
0.02 mm in thickness and is composed mainly of micrites. The
outer organic layer shares the same compositions with the inner
layer, but is thicker, about 0.04 mm in thickness and continuous.
Individual particles are principally ovate in outline and comprise cryptocrystalline organic pellets, which are similar to the
Late Jurassic−Early Cretaceous fecal pellets reported from the
Bavaria (Flügel, 2004) and modern fecal pellets from the Coorong Lake in Australia (Scholle and Ulmer-Scholle, 2003).
These oval particles are arranged regularly along the case walls
with similar sizes and shapes. They, however, usually appear
out-of-order on the bottom of the tubes. The particles appear
baculiform shapes with rounded ends in cross section and are
nearly circular in longitudinal section (Fig. 6). SEM imaging
analysis shows that these pellets are sub-cylindrical in outline
and elliptic in cross section, and comprise primarily calcium
carbonates (Fig. 7).
4 DISCUSSION
4.1 Comparison with Other Fossil Caddisfly Larval Cases
Elsewhere in the World
A few collections of the Meosozic–Cenozoic caddisfly
(Trichoptera) cases have been reported worldwide. The Liupanshan cases are significantly smaller than the Early Cretaceous counterparts reported from southern England (Jarzembowski, 1995), Siberia of Far East, Russia (Ivanov, 2006) and
Liaoning of northeastern China (Huang et al., 2009). The morphologically similar caddisfly cases have also been described
from the Eocene Green River Formation of the western US
(Leggitt and Cushman, 2001), but they are significantly smaller
than the Liupanshan cases. Paik (2005) also reported a
Exceptionally Preserved Caddisfly Larval Cases (Insecta) from the Lower Cretaceous of the Liupanshan Basin, Western China
197
Figure 5. Morphology and micro-structures of the Early Cretaceous caddisfly larval cases. All came from Bed 4 of the
Yadongshan Formation in the Yaoshan Section in Tongxin, Ningxia (scale bar is 1 mm). (a) Individual coniform larval case; (b)
larval case colonies showing no connecting structures between the single cases; (c) larval case colonies showing both open
ends; (d)–(g) cross sections showing that case tube wall comprises three layers: inner dark organic layer (IL), medium pellet
layer (ML) and outer dark organic layer (OL); (h) longitudinal section showing that the case colony comprises two subparallel rows. Note the pellets in tube walls have a similar size and shape to one another.
Figure 6. Diagrams showing arrangements of cemented
particles in case wall. (a) Pellets arranged in planar cross
section of caddisfly cases; (b) pellets arranged in longitudinal section; (c) 3-demension view of caddisfly cases showing
pellet arrangement, scale bar is 1 mm.
microbial caddisfly bioherms from the Early Cretaceous Jinju
Formation of the Jahyeri area, Korea. The Jahyeri caddisfly
bioherms are similar to the Liupanshan caddisfly bioherms in
terms of dome outline and size. Single cases in both bioherms
were stuck together by microbes and form layers to construct
high-relief bioherms. However, the Liupanshan caddisfly bioherms are better preserved with more distinguished layers than
Korean bioherms. The pronounced tiny particles of cryptocrystalline pellets filled in the medium layer of wall tube of single
cases were not observed in Korean caddisfly cases.
Moreover, the tubular portable cases and cemented pellets
were controlled by the habitats of the caddisfly larvae. There
are principally three types of the pellets cemented in larval case
walls (Table 1). The first type, with caddis larvae cases dispersed in streams and lakes, is constructed of sand grains. The
second type has the case walls constructed by leaf pieces of
both angiosperm and gymnosperm fragments, fragmented ostracod valves, and fish bones/scales. Their case-building caddisfly larvae usually inhabit the lentic ecosystems such as pond
and lake. The third type, with the larval cases being constructed
by organic pellets, is usually preserved in some restricted environments such as lagoons (especially supersaline lagoons).
As stated above, the Liupanshan Group succession was
referred to be deposited in dry and hot sub-tropical temperate
climatic conditions by integrating sedimentary facies, palynofloral assemblages (Li and Du, 2006; Liu, 1983), organic
carbon isotopic signals (Bai et al., 2003), and changes of chromaticity and magnetic susceptibility (Dai et al., 2010, 2009).
Thus, the Liupanshan caddisfly cases possess tube walls constructed by organic pellets and are mainly preserved in the restricted, salty lake. They therefore share the similar living behaviors to those larval cases reported from the Early Cretaceous
Baissa Formation of Siberia, Russia (Ivanov, 2006).
Xin He, Zhong-Qiang Chen, Zongsheng Lu, Jun Li, Wei Hu, Shengfu Li and Zhitao Xu
198
Table 1
Cemented particle types of the caddisfly case tube walls
Tube wall components
Stratigraphic unit
Age
Locality
References
Ostracod valves
Leaf pieces
Green River Fm.
Lataha Fm.
Eocene
Miocene
Wyoming, US
Washington, US
Bradley, 1924
Lewis, 1970a
Leaf pieces
Windrow Fm.
Cretaceous
Minnesoda, US
Lewis, 1970b
Leaf pieces
Peterson and Morman
Creeks Fms.
Oligocene
Montana, US
Lewis, 1972
Conchostracan valves, fish
bones/scales, pellets,
bivalve fragments
Wealden Group
Early Cretaceous
South England, UK
Jarzembowski,
1995
Sand grains of
Morrison Fm.
Late Jurassic
Colorado, US
Carbonate particles
Green River Fm.
Eocene
Wyoming, US
Carbonate particles, ooids,
ostracod valves, quartz
grains
Green River Fm.
Eocene
Wyoming, US
Other caddisfly cases, sand
grains, vegetable material
?
Modern
Peñalara National
Park, Spain
Hasiotis et al.,
1998
Loewen et al.,
1999
Leggitt et al.,
2007; Leggitt
and Loewen,
2002; Leggitt
and Cushman,
2001
Boyero and
Barnard, 2004
Fine sands, wood fragments, limemudstone clasts
Jinju Fm.
Early Cretaceous
Jahyeri, Korea
Paik, 2005
Plant material
Kundur Fm.
Late Cretaceous
Fish bones and scales
Wealden Group
Sukatsheva,
2005
Heads, 2006
Pellets (fecal particles)
Baissa Fm.
Sand grains, leaf pieces
Daohugou Fauna Unit
Early Cretaceous
Early Cretaceous
Middle Jurassic
Amur Region, Russia
Southern England,
UK
Siberia, Russia
Pingquan, China
Ostracod carapace, bivalve
fragments
Jehol Fauna Unit
Early Cretaceous
Yixian, NE China
Huang et al.,
2009
Huang et al.,
2009
Sand grains, leaf pieces
Lushangfen Horde
Fm.
Early Cretaceous
Lushangfen, NE
China
Ivanov, 2006
Huang et al.,
2009
Fm. Formation.
4.2
Ichnology of Caddisfly Cases
Of the better defined 11 ichnogenera proposed for caddisfly cases in terms of various grain compositions in tubular case
walls (Table 2), five ichnogenera Conchindusia Vyalov and
Sukatsheva, 1976, Folindusia Berry, 1928, Indusia Sukatsheva,
1993, Pelindusia Vyalov and Sukatsheva, 1976, and Piscindusia Jarzembowski, 1995 possess tube walls that are made of
fragments of plant leaves or invertebrate shells; four ichnogenera Scyphindusia Sukatsheva, 1985, Secrindusia Sukatsheva,
1982, Terrindusia Sukatsheva, 1993, and Tektonargus Hasiotis
in Hasiotis et al., 1998 embrace tube walls that are comrpised
with sand grains or secretory material. Both Ostracindusia
Vyalov, 1973 and Coprindusia Ivanov, 2006 having tube walls
that are made of ovoid pellets, and thus are most allied to the
Liupanshan laval cases. These two ichnogenera, however, also
differ from the Liupanshan cases in having a larger size and
and components of pellets. Of these, Ostracindusia, 12−14 mm
long and 4 mm in diameter, embraces wall pellets having a
diameter up to 0.67 mm and compositions of decalcified ostracod valves and carbonate particles. Coprindusia is 8−14 mm
long and 3−4 mm wide and its wall pellets are equal in size and
shape (0.3−0.4 mm in length and 0.1−0.3 mm in diameter) and
comprise fecal particles of aquatic animals, which are arranged
perpendicular to or at a small angle to the case axis (Gorman et
al., 2008; Ivanov, 2006).
As described above, the Liupanshan caddisfly cases were
constructed with organic pellets which were likely made of
bacterial algae and fecal particles derived from aquatic invertebrates. They are mostly 4−17 mm long and 1.5−2.9 mm in
diameter (Figs. 3e−3f). These characters therefore justify a
tentative assignment of the Liupanshan caddisfly cases to Coprindusia, although some minor differences exist between the
Russian ichnogenus and Liupanshan materials.
4.3
Case-Makers
A wide variety of candidates such as serpulids, vestimen-
Exceptionally Preserved Caddisfly Larval Cases (Insecta) from the Lower Cretaceous of the Liupanshan Basin, Western China
modern Oocardium possesses bifurcate tubes (Bradley, 1974).
As a result, the tubular burrows built by the above organisms
are readily different from the Liupanshan caddisfly larval cases.
Modern caddisfly larval cases are open at both ends, although
the caudal end may be partially closed, and composed of
sand-size quartz grains of 2.5–30 mm in length (Leggitt and
Loewen, 2002). They inhabit mainly springs, small streams,
lakes, and wetlands, even brackish water (Daniel et al., 2009;
Moor and Ivanov, 2008; Greenwood et al., 2003; Johansson,
1991). They aggregate when pupating or overwintering
(Vvtenis, 1985). Total 29 of the extant and extinct caddisfly
families contain taxa, which are capble of building cases. Of
these, five families Phryganeidae, Brachycentridae, Lepidostomatidae, Calamoceratidae, and Leptoceridae are known to
persist from the Early Cretaceous (Paik, 2005; Ivanov and Sukatsheva, 2002). Both the Phryganeidae and Leptoceridae possess lentic biotope (pond and lake) (Leggitt et al., 2007; Paik,
2005; Mackay and Wiggins, 1979). The larval cases of the
Phryganeidae are generally larger than 20 mm in length and
tiferans, dentaliid, tentaculitoid, siphonodendron, and some
algae have been proposed for builders of such tubular traces,
which are similar to the caddisfly larval cases. Of these, both
tentaculitoid and siphonodendron are extinct marine invertebrates. The overwhelming majority of serpulids also inhabit
marine niches, except Microconchus pussilus (Martin, 1809)
which has been reported from terrestrial niches and possesses a
rather small calcareous tube, 2–5 mm in length and 50–200 µm
in diameter (Yang et al., 2015, 2011; Chen et al., 2008; Chen
and Sun, 2001; Ding et al., 1993; Yu and Wang, 1983, 1981;
Chen and Wu, 1979). The vestimentiferans, characteristics of
the cold spring fluid faunas, are cylindric and crooked in outline and possess the tube walls constructed of cryptocrystalline
calcium carbonate (Chen et al., 2007, 2006; Peckmann et al.,
2005; Halanych et al., 1998). The tubes built by the dentaliids
are usually preserved dispersely and their walls are variously
ornamented. Oocardium is one of the few desmids growing
only in highly calcareous waters, the cells of Oocardium secrete tubes of mucilage around which lime is precipitated, but
Table 2
Key characteristics of selected caddisfly case ichnogenera
Ichnogenus
Species
Size (mm)
Tube wall
composition
References
Conchindusia
C. distans
L: 14–23, D: 4–5
Cret.-
Conchostracan valves
Jarzembowski, 1995
P. sukachevae
L: 17–30, D: 3–4
Cret.-
Fish bones/scales
Jarzembowski, 1995
O. vyalovi
L: 12–14, D: 4
Cret.-
Jarzembowski, 1995
Pelindusia
P. percealleni
L: 35, D: 5
Cret.-
Pellets (ostracod valves,
carbonate particles)
Bivalve fragments
Folindusia
F. pinacea
L: 23, D: 7
Jur.-
Leaf fragments
Lewis, 1970a
L: 40, D: 8
Jur.-
Secretory material
Ponomarenko et al., 2009
Terrindusia
S. hydroptiliformis
T. notabilis
L: 15–19, D: 5
Cret.-
Terrigenous materials
Ponomarenko et al., 2009
Coprindusia
C. pallida
L: 8–14, D:
3.1–4.1
L: 12–20, D: 3–4
Cret.-
Pellets (fecal particles)
of aquatic animals
Plant material with ostracod shell fragments
Sand grains
Gorman et al., 2008 ;
Ivanov, 2006
Ponomarenko et al., 2009
Secretary material with
sand grains
Ponomarenko et al., 2009
Piscindusia
Ostracindusia
Scyphindusia
Indusia
I. incredibilis
Tektonargus
T. kollaspilas
Secrindusia
S. admiranda
199
L: 11–14, D:
0.5–3
L: 23, D: 3.5
Age
Cret.Jur.Cret.-
Jarzembowski, 1995
Hosiotis et al., 1998
Figure 7. SEM image (left figure) and EDS analytical results (right figure) of the cemented pellets in case tube walls. White
cross corresponds to analysing point. Element Au indicates gold coating of samples.
200
Xin He, Zhong-Qiang Chen, Zongsheng Lu, Jun Li, Wei Hu, Shengfu Li and Zhitao Xu
composed mainly of wood fragments, whereas the larval cases
of the Leptoceridae are generally 10−20 mm in length and are
constructed of sand grains and some wood fragments (Paik,
2005). Judging by case size and outline as well as composition
and construction pattern of cemented particles in case walls, the
above two families can not accommodate the Liupanshan caddisfly larval cases.
Moreover, Ponomarenko et al. (2009) suggested that a
great number of lacustrine insect hordes became extinct in
Cretaceous and they could also be candidates building such
caddisfly cases. For example, fossil caddisfly cases such as
Conchindusia, Piscindusia, Ostracindusia, and Pelindusia
reported from the Early Cretaceous of southern England were
believed to be built by the extinct Necrotauliidae, Vitimotauliidae, Dysoneuridae, and Plectrotarsidae (Sukatsheva and Jarzembowski, 2001; Jarzembowski, 1995). Similarly, the Liupanshan caddisfly cases may also have been built by some extinct insects. This inference is reinforced by the discovery of
insect wing fossils in association with caddisfly larval cases in
the studied section (Fig. 8). Hong and Li (2004) described insect wing fossils from the caddisfly case-bearing horizons in
the Liupanshan Basin and assigned them to Ningxiapsyche
fangi, which belongs to the Ningxiapsychidae (Trichoptera,
Integripalpia).
The forewing of the Ningxiapsychidae from the late Early
Cretaceous (Aptian–Albian Stage) Naijiahe Formation in
southern Ningxia, China, is 9.1 mm long and 3.5 mm wide
(Hong and Li, 2004). Their larvae inhabited in clean lentic
niches and could construct conoid, portable silk cases, while
the adults live in land. They are holometabolous, typically unlvoltine (Leggitt and Cushman, 2001) and generally emergent
in autumn. Pupation usually requires three weeks and the adult
stage lasts 3–4 weeks (Leggitt and Cushman, 2001).
As consequence, Ningxiapsyche fangi is the candidate for the
potential trace-makers who produced the Liupanshan caddisfly
cases (Fig. 8). They often inhabited nearshore environments, like
other Trichopteriods (Paik, 2005; Leggitt and Cushman, 2001).
Figure 8. The forewing of Ningxiapsyche fangi uncovered from
the same horizon as caddisfly cases (after Hong and Li, 2004).
5
CONCLUSIONS
Small, tubular and unique tube wall compositions indicate
that the tubular fossils of Aptian–Albian age (Early Cretaceous)
from the Liupanshan Basin, western China are assignable to
fossil caddisfly larval case. They resemble both modern caddisfly cases and fossil counterparts. The case wall comprises inner,
medium and outer layers. Both inner and outer layers are composed of organics, while the medium layer consists of tiny particles of cryptocrystalline pellets. The organic pellets were
regularly arranged and perpendicular to the axis of the tube.
Several major ichnologic features such as small size, tubular
shape and tube walls constructed with ovoid pellets indicate
that the Liupanshan caddisfly larval cases are tentatively assignable to ichnogenus Coprindusia. The co-occurrence of
insect forewing fossils of Ningxiapsyche fangi and larval cases
in Liupanshan suggests that the former insects could be the
candidate for case-builders accountable for these exceptionally
preserved caddisfly larval cases. They inhabited a highly
evaporitc, salty lake during the Early Cretaceous.
ACKNOWLEDGMENTS
The authors are grateful to both Xing Huang and Lu Jia for
preparing thin-sections, both Yongling Chen and Lei Shi for assistance in SEM imaging analysis, and Bin Chen for assistance in
photographing these tiny fossils. Two anonymous reviewers are
thanked for their constructive suggestions, which have improved
greatly the quality of the paper. This study was supported by the
973 Program of China (No. 2011CB808800), the 111 Program of
China, Ministry of Education of China, the National Natural Science Foundation of China (No. 41272023), and the research grant
from the State Key Laboratory of Biogeology and Environmental
Geology (No. GBL11206). It is a contribution to the special issue
celebrating the 80th Birthday of Professor Hongfu Yin, China
University of Geosciences (Wuhan).
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